Mintu Turakhia M.D. M.A.S. is a cardiac electrophysiologist, outcomes researcher, and Assistant Professor of Medicine at Stanford University. He is Director of Cardiac Electrophysiology at the Palo Alto VA Health Care System and is an Associate Investigator at the Center for Health Care Evaluation (CHCE). In his clinical role, Dr. Turakhia performs catheter ablation, device implantation, and lead extraction. Dr. Turakhia has an active clinical research program, with funding from AHA, VA, NIH, the medical device industry, and foundations. His research program aims to improve the treatment of heart rhythm disorders, by evaluating quality and variation of care, comparative and cost-effectiveness of therapies, and risk prediction. Dr. Turakhia has extensive expertise in using large administrative and claims databases for this work. His TREAT-AF retrospective study of over 400,000 patients with newly-diagnosed AF is the largest known research cohort of AF patients. His other research interests include technology assessment of new device-based therapies and the impact of changing health policy and reform on the delivery of arrhythmia care. Dr. Turakhia is a Fellow of the American Heart Association, American College of Cardiology, and Heart Rhythm Society.

Clinical Focus

  • Tachycardia, Supraventricular
  • Implantable Defibrillators
  • Cardiology (Heart)
  • Atrial Fibrillation
  • Death, Sudden, Cardiac
  • Clinical Cardiac Electrophysiology
  • Catheter Ablation
  • Arrhythmias, Cardiac

Academic Appointments

Administrative Appointments

  • Director, Cardiac Electrophysiology, Palo Alto VA Health Care System (2008 - Present)
  • Cardiac Electrophysiologist, Stanford Hospital and Clinics (2008 - Present)
  • Member, Electrocardiography and Arrhythmias Committee, American Heart Association (2009 - Present)
  • Member, Young Clinicians and Investigators Committee, American Heart Association Council of Quality and Outcomes Research (2010 - Present)
  • Chair, Writing Group, American Heart Association Telemetry Latency Advisory (2010 - Present)
  • Co-Chairperson, VA Health Services & Research Career Development Conference (2009 - 2010)

Honors & Awards

  • Department of Medicine Teaching Award, Stanford Department of Medicine (12/2010)
  • E. William Hancock Faculty Teaching Award, Stanford Division of Cardiovascular Medicine (6/2010)

Professional Education

  • Board Certification: Clinical Cardiac Electrophysiology, American Board of Internal Medicine (2009)
  • Fellowship:Univ of California San Francisco (2008) CA
  • Fellowship:Univ of California San Francisco (2006) CA
  • Residency:Brigham and Women's Hospital Harvard Medical School (2003) MA
  • Internship:Brigham and Women's Hospital Harvard Medical School (2001) MA
  • Medical Education:Univ of California San Francisco (2000) CA
  • Board Certification: Cardiovascular Disease, American Board of Internal Medicine (2006)
  • Professional Education:UCSF - MAS (2008) CA

Community and International Work

  • Research Chair, Mountain View, CA


    Cardiovascular risk in South Asians

    Partnering Organization(s)

    South Asian Heart Center, El Camino Hospital

    Populations Served

    South Asians


    Bay Area

    Ongoing Project


    Opportunities for Student Involvement


Research & Scholarship

Current Research and Scholarly Interests

Dr. Mintu Turakhia a board-certified internist, cardiologist, and cardiac electrophysiologist and an Instructor at the Stanford University School of Medicine. He directs the Cardiac Electrophysiology program at the Palo Alto VA Health Care System and an Associate Investigator at the Center for Health Care Evaluation (CHCE). As an undergraduate, he studied computer science and molecular biology at the University of California Berkeley (1996). He received his MD at the University of California San Francisco (2000) and completed his Internal Medicine residency at Brigham & Women's Hospital in Boston (2003). He returned to UCSF to for advanced fellowship training in Cardiovascular Medicine (2006) and Cardiac Electrophysiology (2008), while also completing a two-year Master's program in Biostatistics and Clinical Research (2008). As a fellow, he received the American College of Cardiology Merck Foundation Postdoctoral Research Award (2006) and was a finalist for the Laennec Society Young Clinician Award (2006).

Dr. Turakhia's research program aims to improve the treatment of heart rhythm disorders by understanding system- and patient-level variation of arrhythmia treatment in Veterans and their relationship to outcomes. In 2009, he received a VA HSR&D Level II 5-year Career Development Award for a project entitled, "Optimizing Care of Atrial Fibrillation and Flutter in Veterans." He has subsequently received an American Heart Association (AHA) 4-year National Scientist Development Grant (2009) and a 2-year AHA Western States Clinical Research Program Award (deferred).

Dr. Turakhia has over 25 peer-reviewed publications. He is co- chairperson of the 2010 HSR&D CDA annual meeting and a member of the Heart Rhythm Society Clinical Research and Training Committee, AHA Electrocardiography and Arrhythmia Committee, and AHA Young Clinician and Investigators Committee. He is the Associate Web Editor for Archives of Internal Medicine and Associate Editor for the Journal of Interventional Cardiac Electrophysiology.


Journal Articles

  • Warfarin treatment in patients with atrial fibrillation and advanced chronic kidney disease: sins of omission or commission? JAMA : the journal of the American Medical Association Winkelmayer, W. C., Turakhia, M. P. 2014; 311 (9): 913-915

    View details for DOI 10.1001/jama.2014.1781

    View details for PubMedID 24595773

  • Burden, timing, and relationship of cardiovascular hospitalization to mortality among Medicare beneficiaries with newly diagnosed atrial fibrillation. American heart journal Turakhia, M. P., Solomon, M. D., Jhaveri, M., Davis, P., Eber, M. R., Conrad, R., Summers, N., Lakdawalla, D. 2013; 166 (3): 573-580


    Limited data exist on the burden and relationship of cardiovascular (CV) hospitalization to mortality after newly diagnosed with atrial fibrillation (AF).Using a 20% sample of nationwide Medicare Part A and B claims data, we performed a retrospective cohort study of Medicare beneficiaries with newly diagnosed AF (2004-2008). Cox proportional hazards time-varying exposures were used to determine the risk of death among patients with CV hospitalization after AF diagnosis.Of 228,295 patients (mean age 79.6 ± 7.4 years, 56% female), 57% had a CV hospitalization after diagnosis of AF (41% in the first year). The most common primary CV hospitalization diagnoses were AF/supraventricular arrhythmias (21%), heart failure (19%), myocardial infarction (11%), and stroke/transient ischemic attack (7.7%). Incidence rates per 1,000 person-years among patients with and without CV hospitalization were 114 and 87, respectively, for all-cause mortality. After adjustment for covariates and time to CV hospitalization, the hazard of mortality among newly diagnosed AF patients with CV hospitalization, compared with those without CV hospitalization, was higher (hazard ratio 1.22, 95% CI 1.20-1.24).Cardiovascular hospitalization is common in the first year after AF diagnosis. Atrial fibrillation, heart failure, myocardial infarction, and stroke/transient ischemic attack account for half of primary hospitalization diagnosis. Cardiovascular hospitalization is independently associated with mortality, irrespective of time from diagnosis to first hospitalization, and represents a critical inflection point in survival trajectory. These findings highlight the importance of CV hospitalization as a marker of disease progression and poor outcomes. Efforts to clarify the determinants of hospitalization could inform interventions to reduce admissions and improve survival.

    View details for DOI 10.1016/j.ahj.2013.07.003

    View details for PubMedID 24016509

  • US Health Care Policy and Reform: implications for cardiac electrophysiology JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY Turakhia, M. P., Ullal, A. J. 2013; 36 (2): 129-136


    In response to unsustainably rising costs, variable quality and access to health care, and the projected insolvency of vital safety net insurance programs, the federal government has proposed important health policy and regulatory changes in the USA. The US Supreme Court's decision to uphold most of the major provisions of the Affordable Care Act will lead to some of the most sweeping government reforms on entitlements since the creation of Medicare. Furthermore, implementation of new organizational, reimbursement, and health care delivery models will strongly affect the practice of cardiac electrophysiology. In this brief review, we will provide background and context to the problem of rising health care costs and describe salient reforms and their projected impacts on the field and practice of cardiac electrophysiology.

    View details for DOI 10.1007/s10840-012-9773-3

    View details for Web of Science ID 000316749200005

    View details for PubMedID 23397248

  • Differences and trends in stroke prevention anticoagulation in primary care vs cardiology specialty management of new atrial fibrillation: The Retrospective Evaluation and Assessment of Therapies in AF (TREAT-AF) study AMERICAN HEART JOURNAL Turakhia, M. P., Hoang, D. D., Xu, X., Frayne, S., Schmitt, S., Yang, F., Phibbs, C. S., Than, C. T., Wang, P. J., Heidenreich, P. A. 2013; 165 (1): 93-?


    Atrial fibrillation and flutter (AF, collectively) cause stroke. We evaluated whether treating specialty influences warfarin prescription in patients with newly diagnosed AF.In the TREAT-AF study, we used Veterans Health Administration health record and claims data to identify patients with newly diagnosed AF between October 2004 and November 2008 and at least 1 internal medicine/primary care or cardiology outpatient encounter within 90 days after diagnosis. The primary outcome was prescription of warfarin.In 141,642 patients meeting the inclusion criteria, the mean age was 72.3 ± 10.2 years, 1.48% were women, and 25.8% had cardiology outpatient care. Cardiology-treated patients had more comorbidities and higher mean CHADS2 scores (1.8 vs 1.6, P < .0001). Warfarin use was higher in cardiology-treated vs primary care only-treated patients (68.6% vs 48.9%, P < .0001). After covariate and site-level adjustment, cardiology care was significantly associated with warfarin use (odds ratio [OR] 2.05, 95% CI 1.99-2.11). These findings were consistent across a series of adjusted models (OR 2.05-2.20), propensity matching (OR 1.98), and subgroup analyses (OR 1.58-2.11). Warfarin use in primary-care-only patients declined from 2004 to 2008 (51.6%-44.0%, P < .0001), whereas the adjusted odds of warfarin receipt with cardiology care (vs primary care) increased from 2004 to 2008 (1.88-2.24, P < .0001).In patients with newly diagnosed AF, we found large differences in anticoagulation use by treating specialty. A divergent 5-year trend of risk-adjusted warfarin use was observed. Treating specialty influences stroke prevention care and may impact clinical outcomes.

    View details for DOI 10.1016/j.ahj.2012.10.010

    View details for Web of Science ID 000312272900017

    View details for PubMedID 23237139

  • Cost-Effectiveness of Dabigatran Compared With Warfarin for Stroke Prevention in Atrial Fibrillation ANNALS OF INTERNAL MEDICINE Freeman, J. V., Zhu, R. P., Owens, D. K., Garber, A. M., Hutton, D. W., Go, A. S., Wang, P. J., Turakhia, M. P. 2011; 154 (1): 1-U129


    Warfarin reduces the risk for ischemic stroke in patients with atrial fibrillation (AF) but increases the risk for hemorrhage. Dabigatran is a fixed-dose, oral direct thrombin inhibitor with similar or reduced rates of ischemic stroke and intracranial hemorrhage in patients with AF compared with those of warfarin.To estimate the quality-adjusted survival, costs, and cost-effectiveness of dabigatran compared with adjusted-dose warfarin for preventing ischemic stroke in patients 65 years or older with nonvalvular AF.Markov decision model.The RE-LY (Randomized Evaluation of Long-Term Anticoagulation Therapy) trial and other published studies of anticoagulation. The cost of dabigatran was estimated on the basis of pricing in the United Kingdom.Patients aged 65 years or older with nonvalvular AF and risk factors for stroke (CHADS? score ?1 or equivalent) and no contraindications to anticoagulation.Lifetime.Societal.Warfarin anticoagulation (target international normalized ratio, 2.0 to 3.0); dabigatran, 110 mg twice daily (low dose); and dabigatran, 150 mg twice daily (high dose).Quality-adjusted life-years (QALYs), costs (in 2008 U.S. dollars), and incremental cost-effectiveness ratios.The quality-adjusted life expectancy was 10.28 QALYs with warfarin, 10.70 QALYs with low-dose dabigatran, and 10.84 QALYs with high-dose dabigatran. Total costs were $143 193 for warfarin, $164 576 for low-dose dabigatran, and $168 398 for high-dose dabigatran. The incremental cost-effectiveness ratios compared with warfarin were $51 229 per QALY for low-dose dabigatran and $45 372 per QALY for high-dose dabigatran.The model was sensitive to the cost of dabigatran but was relatively insensitive to other model inputs. The incremental cost-effectiveness ratio increased to $50 000 per QALY at a cost of $13.70 per day for high-dose dabigatran but remained less than $85 000 per QALY over the full range of model inputs evaluated. The cost-effectiveness of high-dose dabigatran improved with increasing risk for stroke and intracranial hemorrhage.Event rates were largely derived from a single randomized clinical trial and extrapolated to a 35-year time frame from clinical trials with approximately 2-year follow-up.In patients aged 65 years or older with nonvalvular AF at increased risk for stroke (CHADS? score ?1 or equivalent), dabigatran may be a cost-effective alternative to warfarin depending on pricing in the United States.American Heart Association and Veterans Affairs Health Services Research & Development Service.

    View details for Web of Science ID 000285830900001

    View details for PubMedID 21041570

  • Phenytoin toxicity unlikely to result in arrhythmias-reply. JAMA internal medicine Johnson, C. J., Turakhia, M. P. 2014; 174 (1): 167-168

    View details for DOI 10.1001/jamainternmed.2013.11168

    View details for PubMedID 24394935

  • Adherence and persistence in the use of warfarin after hospital discharge among patients with heart failure and atrial fibrillation. Journal of cardiac failure Eapen, Z. J., Mi, X., Qualls, L. G., Hammill, B. G., Fonarow, G. C., Turakhia, M. P., Heidenreich, P. A., Peterson, E. D., Curtis, L. H., Hernandez, A. F., Al-Khatib, S. M. 2014; 20 (1): 23-30


    Postdischarge adherence and long-term persistence in the use of warfarin among patients with heart failure and atrial fibrillation without contraindications have not been fully described.We identified patients with heart failure and atrial fibrillation who were ≥65 years old, eligible for warfarin, and discharged home from hospitals in the Get With the Guidelines-Heart Failure registry from January 1, 2006, to December 31, 2009. We used linked Medicare prescription drug event data to measure adherence and persistence. The main outcome measures were rates of prescription at discharge, outpatient dispensing, discontinuation, and adherence as measured by the medication possession ratio. We hypothesized that adherence to warfarin would differ according to whether patients received the prescription at discharge. Among 2,691 eligible patients, 1,856 (69.0%) were prescribed warfarin at discharge. Patients prescribed warfarin at discharge had significantly higher prescription fill rates within 90 days (84.5% vs 12.3%; P < .001) and 1 year (91.6% vs 16.8%; P < .001) and significantly higher medication possession ratios (0.78 vs 0.63; P < .001). Among both previous nonusers and existing users, fill rates at 90 days and 1 year and possession ratios were significantly higher among those prescribed warfarin at discharge.One-third of eligible patients with heart failure and atrial fibrillation were not prescribed warfarin at discharge from a heart failure hospitalization, and few started therapy as outpatients. In contrast, most patients who were prescribed warfarin at discharge filled the prescription within 90 days and remained on therapy at 1 year.

    View details for DOI 10.1016/j.cardfail.2013.11.006

    View details for PubMedID 24275703

  • Clinical reminders to providers of patients with reduced left ventricular ejection fraction increase defibrillator referral: a randomized trial. Circulation. Heart failure Gupta, A., Gholami, P., Turakhia, M. P., Friday, K., Heidenreich, P. A. 2014; 7 (1): 140-145


    Background- Many patients who are candidates for implantable cardioverter defibrillators (ICDs) are not referred for potential implantation. We sought to determine if a simple provider reminder would increase referrals. Methods and Results- We identified consecutive patients from January 2007 through July 2010 in the VA Palo Alto Health Care System with a left ventricular ejection fraction <35% on echocardiography. Patients were excluded using available administrative data only (no chart review) if they were known to have an ICD, if they were ≥80 years old, or if they did not have a current primary care or cardiology provider within the system. We randomized patients to no intervention or a clinical note to the provider in the medical record. The outcomes were referral for consideration of defibrillator implantation (primary) and documented discussion (secondary). Of 330 patients with left ventricular ejection fraction ≤35%, 128 were known to have an ICD, 85 were no longer followed in the healthcare system, and 28 were ≥80 years old, leaving 89 patients to be randomized. Forty-six patients were randomized to intervention and 43 to control. Eleven of 46 (24%) intervention patients were referred for consideration of ICD implantation during the following 6 months versus 1 of 43 (2%) control patients (P=0.004). Overall, 31 of 46 (67%) intervention patients versus 19 of 43 (44%) control patients had documentation discussing potential candidacy for defibrillators (P=0.05). Conclusions- In patients with low left ventricular ejection fraction, a simple electronic medical record-based intervention directed to their providers improved the rates of referral for ICD implantation. Clinical Trial Registration- URL: Unique identifier: NCT01217827.

    View details for DOI 10.1161/CIRCHEARTFAILURE.113.000753

    View details for PubMedID 24319096

  • Diagnostic utility of a novel leadless arrhythmia monitoring device. American journal of cardiology Turakhia, M. P., Hoang, D. D., Zimetbaum, P., Miller, J. D., Froelicher, V. F., Kumar, U. N., Xu, X., Yang, F., Heidenreich, P. A. 2013; 112 (4): 520-524


    Although extending the duration of ambulatory electrocardiographic monitoring beyond 24 to 48 hours can improve the detection of arrhythmias, lead-based (Holter) monitors might be limited by patient compliance and other factors. We, therefore, evaluated compliance, analyzable signal time, interval to arrhythmia detection, and diagnostic yield of the Zio Patch, a novel leadless, electrocardiographic monitoring device in 26,751 consecutive patients. The mean wear time was 7.6 ± 3.6 days, and the median analyzable time was 99% of the total wear time. Among the patients with detected arrhythmias (60.3% of all patients), 29.9% had their first arrhythmia and 51.1% had their first symptom-triggered arrhythmia occur after the initial 48-hour period. Compared with the first 48 hours of monitoring, the overall diagnostic yield was greater when data from the entire Zio Patch wear duration were included for any arrhythmia (62.2% vs 43.9%, p <0.0001) and for any symptomatic arrhythmia (9.7% vs 4.4%, p <0.0001). For paroxysmal atrial fibrillation (AF), the mean interval to the first detection of AF was inversely proportional to the total AF burden, with an increasing proportion occurring after 48 hours (11.2%, 10.5%, 20.8%, and 38.0% for an AF burden of 51% to 75%, 26% to 50%, 1% to 25%, and <1%, respectively). In conclusion, extended monitoring with the Zio Patch for ≤14 days is feasible, with high patient compliance, a high analyzable signal time, and an incremental diagnostic yield beyond 48 hours for all arrhythmia types. These findings could have significant implications for device selection, monitoring duration, and care pathways for arrhythmia evaluation and AF surveillance.

    View details for DOI 10.1016/j.amjcard.2013.04.017

    View details for PubMedID 23672988

  • Outcomes after kidney transplantation of patients previously diagnosed with atrial fibrillation. American journal of transplantation Lenihan, C. R., Montez-Rath, M. E., Scandling, J. D., Turakhia, M. P., Winkelmayer, W. C. 2013; 13 (6): 1566-1575


    Little is known about the prevalence and outcomes of patients with atrial fibrillation/flutter (AF) who receive a kidney transplant. We identified all patients who had >1 year of uninterrupted Medicare A+B coverage before receiving their first kidney transplant (1997-2009). The presence of pretransplant AF was ascertained from diagnosis codes in Medicare physician claims. We studied the posttransplant outcomes of death, all-cause graft failure, death-censored graft failure and stroke using multivariable Cox regression. Of 62 706 eligible first kidney transplant recipients studied, 3794 (6.4%) were diagnosed with AF prior to kidney transplant. Over a mean follow up of 4.9 years, 40.6% of AF patients and 24.9% without AF died. All-cause and death-censored graft failure were 46.8% and 16.5%, respectively, in the AF group and 36.4% and 19.5%, respectively, in those without AF. Ischemic stroke occurred in 2.8% of patients with and 1.6% of patients without AF. In patients with AF, multivariable-adjusted hazard ratios (95% confidence intervals) for death, graft failure, death-censored graft failure and ischemic stroke were 1.46 (1.38-1.54), 1.41 (1.34-1.48), 1.26 (1.15-1.37) and 1.36 (1.10-1.68), respectively. Pre-existing AF is associated with poor posttransplant outcomes. Special attention should be paid to AF in pretransplant evaluation, counseling and risk stratification of kidney transplant candidates.

    View details for DOI 10.1111/ajt.12197

    View details for PubMedID 23721555

  • Comparative effectiveness of antiarrhythmic drugs on cardiovascular hospitalization and mortality in atrial fibrillation JOURNAL OF COMPARATIVE EFFECTIVENESS RESEARCH Lakdawalla, D., Turakhia, M. P., Jhaveri, M., Mozaffari, E., Davis, P., Bradley, L., Solomon, M. D. 2013; 2 (3): 301-312

    View details for DOI 10.2217/CER.13.19

    View details for Web of Science ID 000319022800018

  • Foreword: health policy and cardiac electrophysiology JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY Hlatky, M. A., Reynolds, M., Turakhia, M. 2013; 36 (2): 97-97

    View details for DOI 10.1007/s10840-013-9789-3

    View details for Web of Science ID 000316749200001

    View details for PubMedID 23479090

  • Bizarre and Wide QRS After Liver Transplant. JAMA internal medicine Johnson, C. J., Scheinman, M. A., Turakhia, M. P. 2013: 1

    View details for PubMedID 23609165

  • Oral Antithrombotic Agents for the Prevention of Stroke in Nonvalvular Atrial Fibrillation A Science Advisory for Healthcare Professionals From the American Heart Association/American Stroke Association STROKE Furie, K. L., Goldstein, L. B., Albers, G. W., Khatri, P., Neyens, R., Turakhia, M. P., Turan, T. N., Wood, K. A. 2012; 43 (12): 3442-3453

    View details for Web of Science ID 000311497600063

    View details for PubMedID 22858728

  • Trends in the Incidence of Atrial Fibrillation in Older Patients Initiating Dialysis in the United States CIRCULATION Goldstein, B. A., Arce, C. M., Hlatky, M. A., Turakhia, M., Setoguchi, S., Winkelmayer, W. C. 2012; 126 (19): 2293-?


    One sixth of US dialysis patients 65 years of age have been diagnosed with atrial fibrillation/flutter (AF). Little is known, however, about the incidence of AF in this population.We identified 258 605 older patients (?67 years of age) with fee-for-service Medicare initiating dialysis in 1995 to 2007, who had not been diagnosed with AF within the previous 2 years. Patients were followed for newly diagnosed AF. Multivariable proportional hazard regression was used to examine temporal trends and associations of race and ethnicity with incident AF. We also studied temporal trends in the mortality and risk of ischemic stroke after new AF. Over 514 395 person-years of follow-up, 76 252 patients experienced incident AF for a crude AF incidence rate of 148/1000 person-years. Incidence of AF increased by 11% (95% confidence interval, 5-16) from 1995 to 2007. Compared with non-Hispanic whites, blacks (-30%), Asians (-19%), Native Americans (-42%), and Hispanics (-29%) all had lower rates of incident AF. Mortality after incident AF decreased by 22% from 1995 to 2008. Even more pronounced reductions were seen for incident ischemic stroke during these years.The incidence of AF is high in older patients initiating dialysis in the United States and has been increasing over the 13 years of study. Mortality declined during that time but remained >50% during the first year after newly diagnosed AF. Because data on warfarin use were not available, we were unable to study whether trends toward better outcomes could be explained by higher rates of oral anticoagulation.

    View details for Web of Science ID 000310744100010

    View details for PubMedID 23032326

  • Anticoagulation for atrial fibrillation in patients on dialysis: are the benefits worth the risks? CURRENT OPINION IN NEPHROLOGY AND HYPERTENSION Shen, J. I., Turakhia, M. P., Winkelmayer, W. C. 2012; 21 (6): 600-606


    Atrial fibrillation is common among patients with end-stage renal disease undergoing hemodialysis. Although oral anticoagulation is recommended for stroke prevention in most patients with atrial fibrillation, limited evidence is available to guide treatment in hemodialysis patients with this arrhythmia. We summarize the available evidence on the epidemiology of atrial fibrillation in dialysis patients and review the data on the effectiveness of oral anticoagulation in this population.Atrial fibrillation is increasingly common in patients undergoing chronic hemodialysis, especially among older patients wherein one in six patients is diagnosed with this arrhythmia. Patients with atrial fibrillation experience double the mortality of otherwise similar patients without it. Few hemodialysis patients with atrial fibrillation receive oral anticoagulation, which is consistently associated with excess risks of hemorrhagic stroke. Observational studies did not detect a beneficial association of oral anticoagulation with the risk of ischemic stroke, with some studies describing higher risks of ischemic stroke among warfarin users. New therapeutic options including one oral direct thrombin inhibitor and two oral factor Xa inhibitors have become available, but were not tested in patients with advanced kidney disease.Atrial fibrillation is increasingly common in patients undergoing hemodialysis, yet little is known about the optimal management of these patients. The current evidence does not support net benefits from oral anticoagulation in the dialysis population.

    View details for DOI 10.1097/MNH.0b013e32835856fd

    View details for Web of Science ID 000310061500006

    View details for PubMedID 23079746

  • Latency of ECG Displays of Hospital Telemetry Systems A Science Advisory From the American Heart Association CIRCULATION Turakhia, M. P., Estes, N. A., Drew, B. J., Granger, C. B., Wang, P. J., Knight, B. P., Page, R. L. 2012; 126 (13): 1665-1669

    View details for DOI 10.1161/CIR.0b013e31826ae459

    View details for Web of Science ID 000309260600023

    View details for PubMedID 22927339

  • Abrupt bradycardia and grouped beating during treadmill testing: A mimic of upper rate behavior HEART RHYTHM Woods, C. E., Friday, K., Wang, P., Turakhia, M. P. 2012; 9 (7): 1165-1167

    View details for DOI 10.1016/j.hrthm.2011.12.020

    View details for Web of Science ID 000305616900031

    View details for PubMedID 22209946

  • Incidence and clinical predictors of low defibrillation safety margin at time of implantable defibrillator implantation JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY Cheng, Z., Turakhia, M., Lo, R., Gupta, A., Zei, P. C., Hsia, H. H., Al-Ahmad, A., Wang, P. J. 2012; 34 (1): 93-100


    Determination of the defibrillation safety margin (DSM) is the most common method of testing device effectiveness at the time of implantation of implantable cardioverter defibrillator (ICD) or cardiac resynchronization therapy defibrillator (CRTD). Low DSM remains a problem in clinical practice.The purpose of this study is to ascertain the incidence and clinical predictors of low DSM and the treatment strategies for low DSM in ICD or CRTD recipients.Selected ICD or CRTD recipients from January 2006 to May 2008 who underwent DSM test at the time of implantation were included. Low DSM patients were defined as patients who had a DSM within 10 J of the maximum delivered energy of the device. These patients were compared to patients who had DSM?>?10 J.This study included 243 patients. Of these, 13 (5.3%) patients had low DSM, and 230 patients had adequate DSM. Patients with low DSM had a high prevalence of amiodarone use (69% vs 13%, p?

    View details for DOI 10.1007/s10840-011-9648-z

    View details for Web of Science ID 000303541200013

    View details for PubMedID 22391960

  • The prognostic value of early repolarization with ST-segment elevation in African Americans HEART RHYTHM Perez, M. V., Uberoi, A., Jain, N. A., Ashley, E., Turakhia, M. P., Froelicher, V. 2012; 9 (4): 558-565


    Increased prevalence of classic early repolarization, defined as ST-segment elevation (STE) in the absence of acute myocardial injury, in African Americans is well established. The prognostic value of this pattern in different ethnicities remains controversial.Measure association between early repolarization and cardiovascular mortality in African Americans.The resting electrocardiograms of 45,829 patients were evaluated at the Palo Alto Veterans Affairs Hospital. Subjects with inpatient status or electrocardiographic evidence of acute myocardial infarction were excluded, leaving 29,281 subjects. ST-segment elevation, defined as an elevation of >0.1 mV at the end of the QRS, was electronically flagged and visually adjudicated by 3 observers blinded to outcomes. An association between ethnicity and early repolarization was measured by using multivariate logistic regression. We analyzed associations between early repolarization and cardiovascular mortality by using the Cox proportional hazards regression analysis.Subjects were 13% women and 13.3% African Americans, with an average age of 55 years and followed for an average of 7.6 years, resulting in 1995 cardiovascular deaths. There were 479 subjects with lateral STE and 185 with inferior STE. After adjustment for age, sex, heart rate, and coronary artery disease, African American ethnicity was associated with lateral or inferior STE (odds ratio 3.1; P = .0001). While lateral or inferior STE in non-African Americans was independently associated with cardiovascular death (hazard ratio 1.6; P = .02), it was not associated with cardiovascular death in African Americans (hazard ratio 0.75; P = .50).Although early repolarization is more prevalent in African Americans, it is not predictive of cardiovascular death in this population and may represent a distinct electrophysiologic phenomenon.

    View details for DOI 10.1016/j.hrthm.2011.11.020

    View details for Web of Science ID 000302258100020

    View details for PubMedID 22094072

  • Ability of microvolt T-wave alternans to modify risk assessment of ventricular tachyarrhythmic events: A meta-analysis AMERICAN HEART JOURNAL Gupta, A., Hoang, D. D., Karliner, L., Tice, J. A., Heidenreich, P., Wang, P. J., Turakhia, M. P. 2012; 163 (3): 354-364


    Prior studies have indicated that the magnitude of risk association of microvolt T-wave alternans (MTWA) testing appears to vary with the population studied. We performed a meta-analysis to determine the ability of MTWA to modify risk assessment of ventricular tachyarrhythmic events (VTEs) and sudden cardiac death (SCD) across a series of patient risk profiles using likelihood ratio (LR) testing, a measure of test performance independent of disease prevalence.We identified original research articles published from January 1990 to January 2011 that investigate spectrally derived MTWA. Ventricular tachyarrhythmic event was defined as the total and arrhythmic mortality and nonfatal sustained or implantable cardioverter-defibrillator-treated ventricular tachyarrhythmias. Summary estimates were created for positive and nonnegative MTWA results using a random-effects model and were expressed as positive (LR+) and negative (LR-) LRs.Of 1,534 articles, 20 prospective cohort studies met our inclusion criteria, consisting of 5,945 subjects predominantly with prior myocardial infarction or left ventricular dysfunction. Although there was a modest association between positive MTWA and VTE (relative risk 2.45, 1.58-3.79) and nonnegative MTWA and VTE (3.68, 2.23-6.07), test performance was poor (positive MTWA: LR+ 1.78, LR- 0.43; nonnegative MTWA: LR+ 1.38, LR- 0.56). Subgroup analyses of subjects classified as prior VTE, post-myocardial infarction, SCD-HeFT type, and MADIT-II type had a similar poor test performance. A negative MTWA result would decrease the annualized risk of VTE from 8.85% to 6.37% in MADIT-II-type patients and from 5.91% to 2.60% in SCD-HeFT-type patients.Despite a modest association, results of spectrally derived MTWA testing do not sufficiently modify the risk of VTE to change clinical decisions.

    View details for DOI 10.1016/j.ahj.2011.11.021

    View details for Web of Science ID 000301597200010

    View details for PubMedID 22424005

  • Left Atrial Function Predicts Heart Failure Hospitalization in Subjects With Preserved Ejection Fraction and Coronary Heart Disease Longitudinal Data From the Heart and Soul Study JOURNAL OF THE AMERICAN COLLEGE OF CARDIOLOGY Welles, C. C., Ku, I. A., Kwan, D. M., Whooley, M. A., Schiller, N. B., Turakhia, M. P. 2012; 59 (7): 673-680


    This study sought to determine whether left atrial (LA) dysfunction predicts heart failure (HF) hospitalization in subjects with preserved baseline ejection fraction (EF).Among patients with preserved EF, factors leading to HF are not fully understood. Cross-sectional studies have demonstrated LA dysfunction at the time of HF, but longitudinal data on antecedent atrial function are lacking.We performed resting transthoracic echocardiography in 855 subjects with coronary heart disease and EF ?50%. Left atrial functional index (LAFI) was calculated as ([LA emptying fraction × left ventricular outflow tract-velocity time integral] / [indexed LA end-systolic volume]), where LA emptying fraction was defined as (LA end-systolic volume--LA end-diastolic volume) / LA end-systolic volume. We used Cox models to evaluate the association between LAFI and HF hospitalization.Over a median follow-up of 7.9 years, 106 participants (12.4%) were hospitalized for HF. Rates of HF hospitalization were inversely proportional to quartile (Q) of LAFI: Q1, 47 per 1,000 person-years; Q2, 18.3; Q3, 9.6; and Q4, 5.3 (p < 0.001). Each standard deviation decrease in LAFI was associated with a 2.6-fold increased hazard of adverse cardiovascular outcomes (unadjusted hazard ratio: 2.6, 95% confidence interval: 2.1 to 3.3, p < 0.001), and the association persisted even after adjustment for clinical risk factors, N-terminal pro-B-type natriuretic peptide, and a wide range of echocardiographic parameters (adjusted hazard ratio: 1.5, 95% confidence interval: 1.0 to 2.1, p = 0.05).Left atrial dysfunction independently predicts HF hospitalization in subjects with coronary heart disease and preserved baseline EF. The LAFI may be useful for HF risk stratification, and LA dysfunction may be a potential therapeutic target.

    View details for DOI 10.1016/j.jacc.2011.11.012

    View details for Web of Science ID 000300393900008

    View details for PubMedID 22322084

  • Cost-effectiveness of pharmacologic and invasive therapies for stroke prophylaxis in atrial fibrillation JOURNAL OF CARDIOVASCULAR MEDICINE Solomon, M. D., Ullal, A. J., Hoang, D. D., Freeman, J. V., Heidenreich, P., Turakhia, M. P. 2012; 13 (2): 86-96


    Atrial fibrillation is an abnormal heart rhythm characterized by rapid, disorganized activation (fibrillation) of the left and right atria of the heart, and is responsible for 15% of 700,000 strokes in the United States each year. There are multiple pharmacologic and nonpharmacologic therapies used for stroke prevention in atrial fibrillation, including vitamin K antagonists such as warfarin, antiplatelet agents such as aspirin and clopidogrel, and newer agents such as dabigatran, rivaroxaban and apixaban. Nonpharmacologic therapies involve excluding the left atrial appendage from the systemic circulation by surgical ligation or excision, percutaneous ligation, or endovascular implantation of a left atrial occlusion device. Because atrial fibrillation-related stroke is preventable, a comparison of the value of these interventions by cost-effectiveness analysis (CEA) could inform clinical and health policy recommendations. In this article, we review the principles of CEA and identify 11 articles that examine CEA of stroke prophylaxis strategies in atrial fibrillation. Although most studies evaluate aspirin and warfarin across a variety of atrial fibrillation stroke risk profiles, we also review new literature on new pharmacologic therapies such as direct thrombin inhibitors and discuss the potential value of device-based therapies.

    View details for DOI 10.2459/JCM.0b013e32834f23cf

    View details for Web of Science ID 000299652200002

    View details for PubMedID 22193838

  • Early Repolarization in an Ambulatory Clinical Population CIRCULATION Uberoi, A., Jain, N. A., Perez, M., Weinkopff, A., Ashley, E., Hadley, D., Turakhia, M. P., Froelicher, V. 2011; 124 (20): 2208-2214


    The significance of early repolarization, particularly regarding the morphology of the R-wave downslope, has come under question.We evaluated 29 281 resting ambulatory ECGs from the VA Palo Alto Health Care System. With PR interval as the isoelectric line and amplitude criteria ?0.1 mV, ST-segment elevation is defined at the end of the QRS, J wave as an upward deflection, and slur as a conduction delay on the QRS downstroke. Associations of ST-segment elevation patterns, J waves, and slurs with cardiovascular mortality were analyzed with Cox analysis. With a median follow-up of 7.6 years, there were 1995 cardiac deaths. Of 29 281 subjects, 87% were male (55±14 years) and 13% were female (56±17 years); 13% were black, 6% were Hispanic, and 81% were white or other. Six hundred sixty-four (2.3%) had inferior or lateral ST-segment elevation: 185 (0.6%) in inferior leads and 479 (1.6%) in lateral leads, 163 (0.6%) in both, and 0.4% had global elevation. A total of 4041 ECGs were analyzed with enhanced display, and 583 (14%) had J waves or slurring, which were more prevalent in those with than in those without ST-segment elevation (61% versus 13%; P<0.001). ST-segment elevation occurred more in those with than in those without J waves or slurs (12% versus 1.3%; P<0.001). Except when involving only inferior leads, all components of early repolarization were more common in young individuals, male subjects, blacks, and those with bradycardia. All patterns and components of early repolarization were associated with decreased cardiovascular mortality, but this was not significant after adjustment for age.We found no significant association between any components of early repolarization and cardiac mortality.

    View details for DOI 10.1161/CIRCULATIONAHA.111.047191

    View details for Web of Science ID 000297060700013

    View details for PubMedID 21986288

  • JICE goes "social" JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY Turakhia, M. P. 2011; 32 (2): 79-80


    Social media is transforming health care. The Journal of Interventional Cardiac Electrophysiology (JICE) has launched its own social media presence and is now on Facebook. JICE will post each issue's table of contents, special articles, online-first publications to allow real-time notifications to JICE's readers and fans of our Facebook page. We encourage you to take the plunge and connect to our Facebook page.

    View details for DOI 10.1007/s10840-011-9621-x

    View details for Web of Science ID 000297556800001

    View details for PubMedID 21972151

  • The CHADS(2) score predicts ischemic stroke in the absence of atrial fibrillation among subjects with coronary heart disease: Data from the Heart and Soul Study AMERICAN HEART JOURNAL Welles, C. C., Whooley, M. A., Na, B., Ganz, P., Schiller, N. B., Turakhia, M. P. 2011; 162 (3): 555-561


    We sought to evaluate the prognostic performance of the CHADS(2) score for prediction of ischemic stroke/transient ischemic attack (TIA) in subjects with coronary heart disease (CHD) without atrial fibrillation (AF).In 916 nonanticoagulated outpatients with stable CHD and no AF by baseline electrocardiogram, we calculated CHADS(2) scores (congestive heart failure, hypertension, age ?75 years, diabetes [1 point each], and prior stroke or TIA [2 points]). The primary outcome was time to ischemic stroke or TIA over a mean follow-up of 6.4 ± 2.3 years.Over 5,821 person-years of follow-up, 40 subjects had an ischemic stroke/TIA (rate 0.69/100 person-years, 95% CI 0.50-0.94). Compared with subjects with low (0-1) CHADS(2) scores, those with intermediate (2-3) and high (4-6) CHADS(2) scores had an increased rate of stroke/TIA, even after adjustment for age, tobacco, antiplatelet therapy, statins, and angiotensin inhibitors (CHADS(2) score 2-3: HR 2.4, 95% CI 1.1-5.3, P = .03; CHADS(2) score 4-6: HR 4.0, 95% CI 1.5-10.6, P = .006). Model discrimination (c-statistic = 0.65) was comparable with CHADS(2) model fit in published AF-only cohorts.The CHADS(2) score predicts ischemic stroke/TIA in subjects with stable CHD and no baseline AF. The event rate in non-AF subjects with high CHADS(2) scores (5-6) was comparable with published rates in AF patients with moderate CHADS(2) scores (1-2), a population known to derive benefit from stroke prevention therapies. These findings should inform efforts to determine whether stroke prevention therapies or screening for silent AF may benefit subjects with stable CHD and high CHADS(2) scores.

    View details for DOI 10.1016/j.ahj.2011.05.023

    View details for Web of Science ID 000294447400022

    View details for PubMedID 21884876

  • Dabigatran Compared With Warfarin for Stroke Prevention in Atrial Fibrillation ANNALS OF INTERNAL MEDICINE Freeman, J. V., Turakhia, M. P. 2011; 154 (8): 570-571
  • Quality of Stroke Prevention Care in Atrial Fibrillation Many Moving Targets CIRCULATION-CARDIOVASCULAR QUALITY AND OUTCOMES Turakhia, M. P. 2011; 4 (1): 5-8
  • Inappropriate Pacing in a Patient with Managed Ventricular Pacing: What Is the Cause? HEART RHYTHM Perez, M. V., Al-Ahmad, A. A., Wang, P. J., Turakhia, M. P. 2010; 7 (12)
  • Sudden Cardiac Death and Implantable Cardioverter-Defibrillators AMERICAN FAMILY PHYSICIAN Turakhia, M. P. 2010; 82 (11): 1357-1366


    Sudden cardiac death is a major public health problem, affecting 500,000 patients in the United States annually. An implantable cardioverter-defibrillator (ICD) can terminate malignant ventricular arrhythmias and has been shown to improve survival in high-risk populations. Although sudden cardiac death is a heterogeneous condition, left ventricular ejection fraction of 35 percent or less remains the single best factor to stratify patients for prophylactic ICD implantation, and randomized trials have shown mortality benefit in this population. Therefore, in patients with heart disease, assessment of ejection fraction remains the most important step to identify patients at risk of sudden cardiac death who would benefit from ICD implantation. Physician understanding of each patient's ICD type, indication, etiology of heart disease, and cardiovascular status is essential for optimal care. If the ICD was placed for secondary prevention, the circumstances relating to the index event should be explored. Evaluation of defibrillator shocks merits careful assessment of the patient's cardiovascular status. Consultation with a subspecialist and interrogation of the ICD can determine if shocks were appropriate or inappropriate and can facilitate management.

    View details for Web of Science ID 000208405500010

  • Using Restriction to Minimize Bias in Observational Studies JAMA-JOURNAL OF THE AMERICAN MEDICAL ASSOCIATION Turakhia, M. P., Heidenreich, P. A. 2010; 304 (21): 2359-2359

    View details for Web of Science ID 000284763900014

    View details for PubMedID 21119082

  • Developing the Safety of Atrial Fibrillation Ablation Registry Initiative (SAFARI) as a collaborative pan-stakeholder critical path registry model: A Cardiac Safety Research Consortium "Incubator" Think Tank AMERICAN HEART JOURNAL Al-Khatib, S. M., Calkins, H., Eloff, B. C., Kowey, P., Hammill, S. C., Ellenbogen, K. A., Marinac-Dabic, D., Waldo, A. L., Brindis, R. G., Wilbur, D. J., Jackman, W. M., Yaross, M. S., Russo, A. M., Prystowsky, E., Varosy, P. D., Gross, T., Pinnow, E., Turakhia, M. P., Krucoff, M. W. 2010; 160 (4): 619-U249


    Although several randomized clinical trials have demonstrated the safety and efficacy of catheter ablation of atrial fibrillation (AF) in experienced centers, the outcomes of this procedure in routine clinical practice and in patients with persistent and long-standing persistent AF remain uncertain. Brisk adoption of this therapy by physicians with diverse training and experience highlights potential concerns regarding the safety and effectiveness of this procedure. Some of these concerns could be addressed by a national registry of AF ablation procedures such as the Safety of Atrial Fibrillation Ablation Registry Initiative that was initially proposed at a Cardiac Safety Research Consortium Think Tank meeting in April 2009. In January 2010, the Cardiac Safety Research Consortium, in collaboration with the Duke Clinical Research Institute, the US Food and Drug Administration, the American College of Cardiology, and the Heart Rhythm Society, held a follow-up meeting of experts in the field to review the construct and progress to date. Other participants included the National Heart, Lung, and Blood Institute; the Centers for Medicare and Medicaid Services; the Agency for Healthcare Research and Quality; the AdvaMed AF working group; and additional industry representatives. This article summarizes the discussions that occurred at the meeting of the state of the Safety of Atrial Fibrillation Ablation Registry Initiative, the identification of a clear pathway for its implementation, and the exploration of solutions to potential issues in the execution of this registry.

    View details for DOI 10.1016/j.ahj.2010.06.044

    View details for Web of Science ID 000282677300010

    View details for PubMedID 20934554

  • Prevalence of Metabolic Syndrome in South Asians Residing in the United States METABOLIC SYNDROME AND RELATED DISORDERS Flowers, E., Molina, C., Mathur, A., Prasad, M., Abrams, L., Sathe, A., Malhotra, D., Basra, R., Malgesini, N., Ratnam, G., Aouizerat, B. E., Turakhia, M. P. 2010; 8 (5): 417-423


    The aim of this study was to define the prevalence of the metabolic syndrome and its component risk factors among individuals of South Asian origin living in the United States.We analyzed baseline data from 1,445 participants enrolled in a cohort study investigating risk factors for cardiovascular disease in South Asians. We defined the metabolic syndrome using the International Diabetes Federation criteria for waist circumference (>90 cm for men; >80 cm, women), triglycerides (>150 mg/dL), high-density lipoprotein cholesterol (HDL-C) (<40 mg/dL (men), < mg/dL (women)), blood pressure (>135/80 mmHg), and fasting glucose (>100 mg/dL).The mean age was 43 +/-10 years, and 30% of participants were women. The prevalence of metabolic syndrome was 27% (31% men vs. 17% women, P < 0.05). Fifty-nine percent of the cohort had high waist circumference (58% men vs. 62% women, P = not significant [N.S.]), 47% had low HDL-C [46% men vs. 48% women (NS)], 19% had elevated triglycerides (23% men vs. 8% women, P < 0.05), 14% had hypertension (16% men vs. 9% women, P < 0.05), and 13% had elevated fasting glucose (18% men vs. 11% women, P < 0.05). The most common metabolic syndrome phenotype is low HDL-C with elevated triglycerides.Although the prevalence of the metabolic syndrome is lower than previous reports of South Asians, the prevalence is still unacceptably high despite the presence of protective demographic factors.

    View details for DOI 10.1089/met.2009.0097

    View details for Web of Science ID 000282809400006

    View details for PubMedID 20939706

  • Inappropriate pacing in a patient with managed ventricular pacing: What is the cause? HEART RHYTHM Perez, M. V., Al-Ahmad, A. A., Wang, P. J., Turakhia, M. P. 2010; 7 (9): 1336-1337


    A case of inappropriate atrial pacing in a patient with a pacemaker programmed with Managed Ventricular Pacing (MVP) mode, a proprietary algorithm in Medtronic devices, is presented. The patient was an 84-year-old woman who presented in sinus rhythm with complete atrioventricular block. A dual-chamber pacemaker was implanted and programmed to an MVP pacing mode. After the implant, the patient developed a relatively slow atrial tachyarrhythmia with 2:1 atrioventricular block and inappropriate atrial pacing, followed by a delay in tracking of the atrial tachyarrhythmia. The mechanisms for these behaviors are described.

    View details for DOI 10.1016/j.hrthm.2010.04.028

    View details for Web of Science ID 000281444100033

    View details for PubMedID 20435165

  • Predicting Heart Failure Hospitalization and Mortality by Quantitative Echocardiography: Is Body Surface Area the Indexing Method of Choice? The Heart and Soul Study JOURNAL OF THE AMERICAN SOCIETY OF ECHOCARDIOGRAPHY Ristow, B., Ali, S., Na, B., Turakhia, M. P., Whooley, M. A., Schiller, N. B. 2010; 23 (4): 406-413


    Echocardiographic measurements of left ventricular (LV) mass, left atrial (LA) volume, and LV end-systolic volume (ESV) predict heart failure (HF) hospitalization and mortality. Indexing measurements by body size is thought to establish limits of normality among individuals varying in body habitus. The American Society of Echocardiography recommends dividing measurements by body surface area (BSA), but others have advocated alternative indexing methods.Echocardiographic measurements were collected in 1024 ambulatory adults with coronary artery disease. LV mass, LA volume, and LV ESV were calculated using truncated ellipse method and biplane method of disk formulae. Comparison between raw measurements and measurements divided by indexing parameters was made by hazard ratios per standard deviation increase in variable and c-statistics for BSA, BSA(0.43), BSA(1.5), height, height(0.25), height(2), height(2.7), body weight (BW), BW(0.26), body mass index (BMI), and BMI(0.27).Mean LV mass was 192 +/- 57 g, mean LA volume was 65 +/- 24 mL, and mean LV ESV was 41 +/- 26 mL. Average height was 171 +/- 9 cm, average BSA was 1.94 +/- 0.22 m(2), and average BMI was 28.4 +/- 5.3 kg/m(2). At an average follow-up of 5.6 +/- 1.8 years, there were 148 HF hospitalizations, 71 cardiovascular (CV) deaths, and 269 all-cause deaths. There was excellent correlation between raw measurements and those indexed by height (r = 0.98-0.99), and moderate correlation between raw measurements and those indexed by BW (r = 0.73-0.94). C-statistics and hazard ratios per standard deviation increase in indexed variables were similar for HF hospitalization, CV mortality, and all-cause mortality. There were no significant differences among indexing methods in ability to predict outcomes.The choice of indexing method by parameters of BSA, height, BW, and BMI does not affect the clinical usefulness of LV mass, LA volume, and LV ESV in predicting HF hospitalization, CV mortality, or all-cause mortality among ambulatory adults with coronary artery disease. Continued use of BSA to index measurements of LV mass, LA volume, and LV ESV is acceptable.

    View details for DOI 10.1016/j.echo.2010.01.019

    View details for Web of Science ID 000276248600012

    View details for PubMedID 20202792

  • Increase in end-systolic volume after exercise independently predicts mortality in patients with coronary heart disease: data from the Heart and Soul Study EUROPEAN HEART JOURNAL Turakhia, M. P., McManus, D. D., Whooley, M. A., Schiller, N. B. 2009; 30 (20): 2478-2484


    The predictive value of changes in global left ventricular (LV) size after exercise has not been studied. Left ventricular end-systolic volume (ESV) is a relatively load-independent echocardiographic marker of contractility that is easily measured. We investigated the role of the change in ESV at rest and after peak exercise on mortality among patients with stable coronary heart disease (CHD).We performed exercise treadmill testing with stress echocardiography in 934 ambulatory subjects with CHD. End-systolic volume was measured immediately before and after exercise using 2D echocardiography. We defined ESV reversal as an increase in ESV after exercise, and we examined the association of ESV reversal with all-cause mortality during a median follow-up of 3.92 years. Of the 934 participants, 199 (21%) had ESV reversal. At the end of follow-up, mortality was higher among participants with ESV reversal than those without (26 vs. 11%; P < 0.001). After adjustment for clinical covariates, ESV reversal remained predictive of all-cause mortality (HR 2.0; 95% CI 1.4-2.9; P = 0.001). The association of ESV reversal with mortality also persisted after adjustment for exercise-induced wall-motion abnormalities (HR 1.7; 95% CI 1.1-2.3, P = 0.006). To determine if the effect of ESV reversal was independent from other echocardiographic measurements, we created a separate model adjusting for resting LV ejection fraction, ESV, end-diastolic volume, and LV mass. End-systolic volume reversal was the only significant predictor of mortality in this model (HR 2.1, 95% CI 1.4-3.0, P < 0.001).End-systolic volume reversal is a novel parameter that independently predicts mortality in patients with CHD undergoing exercise treadmill echocardiography, even after adjustment for a wide range of clinical, echocardiographic, and treadmill exercise variables. Because measurement of ESV is simple, reproducible, and requires no additional imaging views, identification of ESV reversal during exercise echocardiography can provide useful complementary information for risk stratification.

    View details for DOI 10.1093/eurheartj/ehp270

    View details for Web of Science ID 000270985300020

    View details for PubMedID 19578167

  • "Low ejection fraction prophylaxis" with implantable defibrillators in the elderly: Call for a randomized trial? HEART RHYTHM Turakhia, M. P., Wang, P. J. 2009; 6 (8): 1144-1145

    View details for DOI 10.1016/j.hrthm.2009.04.031

    View details for Web of Science ID 000268867700006

    View details for PubMedID 19632625

  • Polymorphic Ventricular Tachycardia? JOURNAL OF HOSPITAL MEDICINE Davis, E., Hoffmayer, K., Turakhia, M., Goldschlager, N. 2009; 4 (2): 140-141

    View details for DOI 10.1002/jhm.419

    View details for Web of Science ID 000263807400010

    View details for PubMedID 19219929

  • Rates and severity of perforation from implantable cardioverter-defibrillator leads: A 4-year study JOURNAL OF INTERVENTIONAL CARDIAC ELECTROPHYSIOLOGY Turakhia, M., Prasad, M., Olgin, J., Badhwar, N., Tseng, Z. H., Lee, R., Marcus, G. M., Lee, B. K. 2009; 24 (1): 47-52


    Although recent case reports and one small single-year observational study report a substantially increased rate of perforation with the St. Jude Riata series defibrillator lead, these results have not been externally validated.From 2004 to 2007, 593 implantable cardioverter-defibrillator (ICD) implants were performed by six faculty and 13 fellows at four University of California, San Francisco, CA, USA and affiliate hospitals. An electronic medical records system was systematically searched to identify clinically significant cases of ICD lead dislodgment or perforation. Of 307 (56%) St. Jude leads (all Riata series 6.3- and 7.3-French leads), 188 (29%) Medtronic leads (including 99 Sprint Fidelis 6.6 French leads), and 98 (15%) Guidant/Boston Scientific leads, there were three perforations in 593 cases (0.51%). One perforation occurred with a Medtronic Sprint Fidelis 6949 lead (0.53%), and two with a St. Jude Riata 1581 lead (0.65%). There were no statistically significant differences in perforation or dislodgement rates between manufacturers or lead models (p = NS for all). In both cases of perforation with the St. Jude Riata leads, the lead tip perforated through the pericardium into the pleural space.In our 4-year series of ICD implants, perforation and dislodgement rates were low, similar across all lead makes and models, and well below published and accepted complication rates. Our findings contradict previously-reported higher rates of perforation with the Riata lead. Registry and product performance reports should also classify complications by severity and outcome to provide a more complete assessment of product safety.

    View details for DOI 10.1007/s10840-008-9308-0

    View details for Web of Science ID 000262987700008

    View details for PubMedID 18855128

  • Wolff-Parkinson-White syndrome: where is the pathway? Indian pacing and electrophysiology journal Turakhia, M. P., Scheinman, M., Badhwar, N. 2009; 9 (2): 130-133


    A 31-year old male presented with atrial fibrillation and ventricular preexcitation that was positive in leads V1-V4, negative in lead II, and positive in lead AVR. The patient was cardioverted and invasive electrophysiologic study was performed. Based on the ECG findings, the coronary sinus and its branches were interrogated during orthodromic atrioventricular reentrant tachycardia. The earliest local activation was seen in the true coronary sinus lumen at the bifurcation of the posterolateral branch. Radiofrequency energy application at this area led to loss of preexcitation. When localizing left septal and posterior accessory pathways, ventricular preexcitation that is both negative in II and positive in AVR has been shown in previous studies to be highly sensitive and specific for a subepicardial location. Therefore, investigation of the coronary sinus and its branches may allow for effective ablation without the need for left ventricular access.

    View details for PubMedID 19308285

  • Impact of Remote Magnetic Catheter Navigation on Ablation Fluoroscopy and Procedure Time PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY Kim, A. M., Turakhia, M., Lu, J., Badhwar, N., Lee, B. K., Lee, R. J., Marcus, G. M., Tseng, Z. H., Scheinman, M., Olgin, J. E. 2008; 31 (11): 1399-1404


    Remote magnetic catheter navigation (RCN) is gaining acceptance in clinical cardiac electrophysiology, but details regarding how RCN affects procedure execution are not well characterized.From January 1, 2005, to November 30, 2007, 721 cases were retrospectively analyzed and compared. Of these, 127 used RCN and 594 used manual catheter navigation (MCN). Data including procedure time, fluoroscopy time, ablation catheter, procedural success, and complications were extracted from our procedure database and compared between RCN and MCN.RCN use significantly decreased fluoroscopy time for atrial fibrillation (AF) ablation (-29 minutes, P < 0.001), atrioventricular nodal reentrant tachycardia ablation (-14 minutes, P < 0.001), and atrioventricular reentrant tachycardia ablation (-18 minutes, P = 0.045). While RCN significantly increased mean procedure time for AF (+36 minutes, P = 0.003) and atypical atrial flutter cases (+116 minutes, P = 0.016), RCN AF procedure time diminished with increasing number of cases performed. Two cases of tamponade occurred during AF ablation using MCN (2.2%, 2 of 91 cases). No tamponade occurred during all 75 AF ablations with RCN.RCN can reduce fluoroscopy time and may reduce complications during catheter ablation. While it may increase total procedure duration, procedure times decrease with increasing operator experience. (PACE 2008; 31:1399-1404).

    View details for DOI 10.1111/j.1540-8159.2008.01202.x

    View details for Web of Science ID 000262203600005

    View details for PubMedID 18950296

  • Prognostic Significance of Increased Left Ventricular Mass Index to Mortality and Sudden Death in Patients With Stable Coronary Heart Disease (from the Heart and Soul Study) AMERICAN JOURNAL OF CARDIOLOGY Turakhia, M. P., Schiller, N. B., Whooley, M. A. 2008; 102 (9): 1131-1135


    Data are limited about the significance of left ventricular (LV) hypertrophy or mass in patients with coronary heart disease (CHD), particularly in the setting of normal ejection fraction (EF). The association of LV mass index with all-cause mortality and sudden death in a cohort with CHD was evaluated. Using transthoracic echocardiography, LV mass normalized to body surface area was measured in 1,016 subjects with stable CHD. Cox proportional hazards models were used to examine the association of LV mass index and LV hypertrophy (LV mass index >95 g/m(2) in women and >115 in men) with time to death and time to sudden or arrhythmic death. Mean LV mass index was 101 +/- 27 g/m(2) in men and 88 +/- 23 in women. During a mean follow-up of 3.55 years, there were 146 deaths and 34 sudden or arrhythmic deaths. Total mortality was higher in subjects with LV hypertrophy (25% vs 11%, p <0.001), as was mortality from sudden or arrhythmic death (6.7% vs 2.2%, p = 0.001). After adjustment for age, gender, cardiovascular risk factors, and medical therapy, LV hypertrophy was associated with both all-cause mortality (hazard ratio 2.0, p <0.001) and sudden or arrhythmic death (hazard ratio 3.1, p = 0.003). Findings were similar in the subgroup with EF > or =55% (mortality hazard ratio 1.8, p = 0.02; sudden and arrhythmic death hazard ratio 3.1, p = 0.02). Analyzed as a continuous variable, every 20-unit increase in LV mass index increased the adjusted hazard of death by 22% (p = 0.001) and adjusted hazard of sudden or arrhythmic death by 40% (p = 0.004). In conclusion, in patients with stable CHD, increased LV mass index was independently associated with all-cause mortality and sudden or arrhythmic death, even in subjects with normal EF.

    View details for DOI 10.1016/j.amjcard.2008.06.030

    View details for Web of Science ID 000261007500003

    View details for PubMedID 18940278

  • Impact of advanced age on survival in patients with implantable cardioverter defibrillators EUROPACE Pellegrini, C. N., Lee, K., Olgin, J. E., Turakhia, M. P., Tseng, Z. H., Lee, R., Badhwar, N., Lee, B., Varosy, P. D. 2008; 10 (11): 1296-1301


    Given the selectivity of clinical trial patients and meager representation of elderly in the major implantable cardioverter defibrillator (ICD) randomized trials (<25%), whether such data apply to elderly patients overall is unclear. The purpose of our study is to understand the influence of age on mortality after ICD implantation.We performed a retrospective cohort study of 502 consecutive patients receiving ICDs from 1993 to 2003 at a single university hospital. The primary predictor was patient age, categorized as <65, 65-75, and >75 years at ICD implantation. The primary outcome was time to death. Mean follow-up was 4 years. Median survival after ICD implantation was 5.3 years among subjects >75 years, less than half that of the youngest group. After adjusting for potential confounders, compared with subjects <65 years of age, patients >75 years [hazard ratio (HR), 4.7; 95% confidence interval (CI), 2.8-7.9; P < 0.001] and those 65-75 years (HR, 2.8; 95% CI, 1.7-4.8; P < 0.001) were at greater risk of death. Increased age was associated with higher total, cardiac, and non-cardiac mortality (all P

    View details for DOI 10.1093/europace/eun253

    View details for Web of Science ID 000260556300009

    View details for PubMedID 18818212

  • The Irritable Heart JOURNAL OF HOSPITAL MEDICINE Turakhia, M. P., Grubb, B. P., Gregoratos, G. 2008; 3 (5): 423-429

    View details for DOI 10.1002/jhm.344

    View details for Web of Science ID 000260690300010

    View details for PubMedID 18951396

  • Knowledge and attitudes of primary care physicians in the management of patients at risk for cardiovascular events BMC FAMILY PRACTICE Doroodchi, H., Abdolrasulnia, M., Foster, J. A., Foster, E., Turakhia, M. P., Skelding, K. A., Sagar, K., Casebeer, L. L. 2008; 9


    Adherence to clinical practice guidelines for management of cardiovascular disease (CVD) is suboptimal. The purposes of this study were to identify practice patterns and barriers among U.S. general internists and family physicians in regard to cardiovascular risk management, and examine the association between physician characteristics and cardiovascular risk management.A case vignette survey focused on cardiovascular disease risk management was distributed to a random sample of 12,000 U.S. family physicians and general internists between November and December 2006.Responses from a total of 888 practicing primary care physicians who see 60 patients per week were used for analysis. In an asymptomatic patient at low risk for cardiovascular event, 28% of family physicians and 37% of general internists made guideline-based preventive choices for no antiplatelet therapy (p < .01). In a patient at high risk for cardiovascular event, 59% of family physicians and 56% of general internists identified the guideline-based goal for serum fasting LDL level (< 100 mg/dl). Guideline adherence was inversely related to years in practice and volume of patients seen. Cost of medications (87.7%), adherence to medications (74.1%), adequate time for counseling (55.7%), patient education tools (47.1%), knowledge and skills to recommend dietary changes (47.8%) and facilitate patient adherence (52.0%) were cited as significant barriers to CVD risk management.Despite the benefits demonstrated for managing cardiovascular risks, gaps remain in primary care practitioners' management of risks according to guideline recommendations. Innovative educational approaches that address barriers may facilitate the implementation of guideline-based recommendations in CVD risk management.

    View details for DOI 10.1186/1471-2296-9-42

    View details for Web of Science ID 000257836800001

    View details for PubMedID 18611255

  • Sudden cardiac death: Epidemiology, mechanisms, and therapy CURRENT PROBLEMS IN CARDIOLOGY Turakhia, M., Tseng, Z. H. 2007; 32 (9): 501-546


    Sudden cardiac death is a major public health problem affecting 500,000 patients annually in the United States alone. The major risk factor for sudden cardiac death is the presence of coronary artery disease, usually in the setting of reduced ejection fraction. Globally, the incidence is expected to rise sharply as the prevalence of coronary artery disease and heart failure continue to increase. However, sudden cardiac death is a heterogeneous condition and may be caused by acute ischemia, structural defects, myocardial scar, and/or genetic mutations. Sudden death may occur even in a grossly normal heart. Beta-blockers can reduce the risk of sudden cardiac death, while implantable cardioverter defibrillators are effective at terminating malignant arrhythmias. Ejection fraction remains the major criterion to stratify patients for defibrillator implantation but this strategy alone is insensitive and nonspecific. Novel clinical, electrophysiologic, and genetic markers have been identified that may increase precision in patient selection for primary prevention therapy. This review discusses the epidemiology, mechanisms, etiologies, therapies, treatment guidelines, and future directions in the management of sudden cardiac death.

    View details for DOI 10.1016/j.cpcardiol.2007.05.002

    View details for Web of Science ID 000249579000002

    View details for PubMedID 17723906

  • Impact of renal function on survival in patients with implantable cardioverter-defibrillators PACE-PACING AND CLINICAL ELECTROPHYSIOLOGY Turakhia, M. P., Varosy, P. D., Lee, K., Tseng, Z. H., Lee, R., Badhwar, N., Scheinman, M., Lee, B. K., Olgin, J. E. 2007; 30 (3): 377-384


    Although chronic renal insufficiency (CRI) is associated with increased cardiac and noncardiac mortality, there is limited data on the relationship between CRI and survival in patients with implantable cardioverter-defibrillators (ICDs), particularly across a wide range of renal function.We studied 507 consecutive patients receiving first-time ICDs from 1993-2003 at a single center. Preimplant serum creatinine measurements were used to determine glomerular filtration rate (GFR) and stage of chronic kidney disease (CKD). The primary outcome was time to death.During a mean follow-up of 4 years, all-cause mortality through completion of follow-up increased stepwise by GFR stage (I: 16%, II: 20%, III: 35%; IV: 40%; V: 50%; P < 0.001 for trend). After multivariate adjustment, CRI was independently associated with death (HR = 1.7, P = 0.02), as were a serum creatinine >or=2.0 mg/dL (HR 2.5, P = 0.003) and the presence of end-stage renal disease (HR 6.8; P < 0.001). For every 10-unit decrease in GFR, the adjusted hazard of death increased 12% (P = 0.04).The presence of CRI prior to implant is independently associated with increased mortality in patients receiving ICDs. The risk is proportional to the degree of renal dysfunction and is apparent even when GFR is only mildly reduced. Differences in mortality are observed within the first year of implant, and patients on dialysis are at highest risk. Because randomized trials of ICDs have not included large numbers of patients with moderate or severe renal disease, our findings may have important implications in prognosis and case selection of patients who otherwise meet current indications for ICD implantation.

    View details for Web of Science ID 000244886500011

    View details for PubMedID 17367357

  • Association of platelet count with residual thrombus in the myocardial infarct-related coronary artery among patients treated with fibrinolytic therapy for ST-segment elevation acute myocardial infarction AMERICAN JOURNAL OF CARDIOLOGY Turakhia, M. P., Murphy, S. A., Pinto, T. L., Antman, E. M., Giugliano, R. P., Cannon, C. P., Braunwald, E., Gibson, C. M. 2004; 94 (11): 1406-1410


    A higher platelet count is independently associated with the presence of residual thrombus in the infarct-related artery after administration of fibrinolytic therapy, even after multivariate adjustment.

    View details for DOI 10.1016/j.amjcard.2004.08.015

    View details for Web of Science ID 000225529600009

    View details for PubMedID 15566912

  • Sequential risk stratification using TIMI risk score and TIMI flow grade among patients treated with fibrinolytic therapy for ST-segment elevation acute myocardial infarction AMERICAN JOURNAL OF CARDIOLOGY Karmpaliotis, D., Turakhia, M. P., Kirtane, A., Murphy, S. A., Kosmidou, I., Morrow, D. A., Giugliano, R. P., Cannon, C. P., Antman, E. M., Braunwald, E., Gibson, C. M. 2004; 94 (9): 1113-1117


    In the setting of ST-segment elevation myocardial infarction (STEMI), the Thrombolysis In Myocardial Infarction (TIMI) risk score (TRS) and indexes of epicardial and myocardial perfusion are associated with mortality. The association between TRS at presentation and angiographic indexes of epicardial and myocardial perfusion after reperfusion therapy has not been investigated. We hypothesized that TRS, TIMI flow grade (TFG), and TIMI myocardial perfusion grade (TMPG) would provide independent prognostic information and that angiographic indexes of poor flow and perfusion would be associated with a higher TRS. TRS and angiographic data were evaluated in 3,801 patients from the TIMI 4, 10A, 10B, 14, 20, 23, and 24 trials. Within each TRS stratum (TRS 0 to 2, 3 to 4, >/=5), 30-day mortality increased stepwise among patients with impaired TFG at 60 minutes after fibrinolytic administration. In a multivariate model adjusting for the TRS strata, impaired TMPG (0/1) was independently associated with higher mortality (odds ratio 2.28, p = 0.018). In a multivariate model adjusting for the TFG and infarct location, the likelihood of impaired TMPG (0/1) was greater among intermediate-risk (TRS 3 to 4) and high-risk (TRS >/=5) patients than among low-risk (TRS 0 to 2) patients (odds ratio 1.43, p = 0.019 and 1.50, p = 0.055, respectively). Thus, impaired epicardial flow and myocardial perfusion are independently associated with increased 30-day mortality among patients identified by TRS as high risk, although there is no synergism between either TFG or TMPG and TRS. High TRS at presentation is associated with abnormal myocardial perfusion, even after adjusting for possible confounders.

    View details for DOI 10.1016/j.amjcard.2004.07.075

    View details for Web of Science ID 000224837500002

    View details for PubMedID 15518603

  • Association of the Fibonacci Cascade with the distribution of coronary artery lesions responsible for ST-segment elevation myocardial infarction AMERICAN JOURNAL OF CARDIOLOGY Gibson, C. M., Gibson, W. J., Murphy, S. A., Marble, S. J., McCabe, C. H., Turakhia, M. P., Kirtane, A. J., Karha, J., Aroesty, J. M., Giugliano, R. P., Antman, E. M. 2003; 92 (5): 595-597


    This is the first study to demonstrate the appearance of the Fibonacci Cascade within the distribution of coronary artery lesions in the human heart. The propensity for this ratio to appear in nature may also be because this ratio optimizes the efficiency of packing structures in a limited space in such a way that wasted space is minimized and the supply of energy or nutrients is optimized.

    View details for DOI 10.1016/S0002-9149(03)00731-8

    View details for Web of Science ID 000185060700020

    View details for PubMedID 12943884

  • Meperidine and alfentanil do not reduce the gain or maximum intensity of shivering ANESTHESIOLOGY Ikeda, T., Sessler, D. I., Tayefeh, F., Negishi, C., Turakhia, M., Marder, D., Bjorksten, A. R., Larson, M. D. 1998; 88 (4): 858-865


    Thermoregulatory shivering can be characterized by its threshold (triggering core temperature), gain (incremental intensity increase with further core temperature deviation), and maximum intensity. Meperidine (a combined mu- and kappa-agonist) treats shivering better than equianalgesic doses of pure mu-opioid agonists. Meperidine's special antishivering action is mediated, at least in part, by a disproportionate decrease in the shivering threshold. That is, meperidine decreases the shivering threshold twice as much as the vasoconstriction threshold, whereas alfentanil (a pure mu-agonist) decreases the vasoconstriction and shivering thresholds comparably. However, reductions in the gain or maximum shivering intensity might also contribute to the clinical efficacy of meperidine. Accordingly, we tested the hypothesis that meperidine reduces the gain and maximum intensity of shivering much more than alfentanil does.Ten volunteers were each studied on three separate days: (1) control (no drug); (2) a target total plasma meperidine concentration of 1.2 microg/ml; and (3) a target plasma alfentanil concentration of 0.2 microg/ml. Skin temperatures were maintained near 31 degrees C, and core temperatures were decreased by central-venous infusion of cold lactated Ringer's solution until maximum shivering intensity was observed. Shivering was evaluated using oxygen consumption and electromyography. A sustained increase in oxygen consumption identified the shivering threshold. The gain of shivering was calculated as the slope of the oxygen consumption versus core temperature regression, and as the slope of electromyographic intensity versus core temperature regression.Meperidine and alfentanil administration significantly decreased the shivering thresholds. However, neither meperidine nor alfentanil reduced the gain of shivering, as determined by either oxygen consumption or electromyography. Opioid administration also failed to significantly decrease the maximum intensity of shivering.The authors could not confirm the hypothesis that meperidine reduces the gain or maximum intensity of shivering more than alfentanil does. These results suggest that meperidine's special antishivering effect is primarily mediated by a disproportionate reduction in the shivering threshold.

    View details for Web of Science ID 000073024700003

    View details for PubMedID 9579492

  • Isoflurane alters shivering patterns and reduces maximum shivering intensity ANESTHESIOLOGY Ikeda, T., Kim, J. S., Sessler, D. I., Negishi, C., Turakhia, M., Jeffrey, R. 1998; 88 (4): 866-873


    Shivering can be characterized by its threshold (triggering core temperature), gain (incremental intensity increase with further core hypothermia), and maximum response intensity. Isoflurane produces a clonic muscular activity that is not a component of normal shivering. To the extent that clonic activity is superimposed on normal thermoregulatory shivering, the gain of shivering might be increased during isoflurane anesthesia. Conversely, volatile anesthetics decrease systemic oxygen consumption and peripherally inhibit skeletal muscle strength, which might limit maximum intensity despite central activation. The purpose of the present study was, therefore, to evaluate the effect of isoflurane shivering patterns and the gain and maximum intensity of shivering.Ten volunteers were each studied in two separate protocols: (1) control (no drug) and (2) 0.7% end-tidal isoflurane. On each day, the mean skin temperature was maintained at 31 degrees C. Core temperature was then reduced by infusion of cold fluid until shivering intensity no longer increased. The core temperature triggering the initial increase in oxygen consumption defined the shivering threshold. The gain of shivering was defined by the slope of the core temperature versus oxygen consumption regression. Pectoralis and quadriceps electromyography was used to evaluate anesthetic-induced facilitation of clonic (5-7 Hz) muscular activity.Isoflurane significantly decreased the shivering threshold from 36.4 +/- 0.3 to 34.2 +/- 0.8 degrees C. The increase in oxygen consumption was linear on the control day and was followed by sustained high-intensity activity. During isoflurane administration, shivering was characterized by bursts of intense shivering separated by quiescent periods. Isoflurane significantly increased the gain of shivering (as calculated from the initial increase), from -684 +/- 266 to -1483 +/- 752 ml x min(-1) x degrees C(-1). However, isoflurane significantly decreased the maximum intensity of shivering, from 706 +/- 144 to 489 +/- 80 ml/min. Relative electromyographic power in frequencies associated with clonus increased significantly when the volunteers were given isoflurane.These data indicate that isoflurane anesthesia markedly changes the overall pattern of shivering during progressive hypothermia from a linear increase to an unusual saw-tooth pattern. They further suggest that clonic muscular activity combines with shivering to increase the initial gain of shivering during isoflurane anesthesia, but that isoflurane peripherally inhibits the maximum expression of shivering.

    View details for Web of Science ID 000073024700004

    View details for PubMedID 9579493

  • Epidural anesthesia reduces and gain and maximum intensity of shivering ANESTHESIOLOGY Kim, J. S., Ikeda, T., Sessler, D. I., Turakhia, M., Jeffrey, R. 1998; 88 (4): 851-857


    Shivering can be characterized by its threshold (triggering core temperature), gain (incremental intensity increase), and maximum intensity. The gain of shivering might be preserved during epidural or spinal anesthesia if control mechanisms compensate for lower-body paralysis by augmenting the activity of upper-body muscles. Conversely, gain will be reduced approximately by half if the thermoregulatory system fails to compensate. Similarly, appropriate regulatory feedback might maintain maximum shivering intensity during regional anesthesia. Accordingly, the gain and maximum intensity of shivering during epidural anesthesia were determined.Seven volunteers participated on two randomly ordered study days. On one day (control), no anesthesia was administered; on the other, epidural anesthesia was maintained at a T8 sensory level. Shivering, at a mean skin temperature near 33 degrees C, was provoked by central-venous infusion of cold fluid; core cooling continued until shivering intensity no longer increased. Shivering was evaluated by systemic oxygen consumption and electromyography of two upper-body and two lower-body muscles. The core temperature triggering an increase in oxygen consumption identified the shivering threshold. The slopes of the oxygen consumption versus core temperature and electromyographic intensity versus core temperature regressions identified systemic and regional shivering gains, respectively.The shivering threshold was reduced by epidural anesthesia by approximately 0.4 degrees C, from 36.7 +/- 0.6 to 36.3 +/- 0.5 degrees C (means +/- SD; P < 0.05). Systemic gain, as determined by oxygen consumption, was reduced from -581 +/- 186 to -215 +/- 154 ml x min(-1) x degrees C(-1) (P < 0.01). Lower-body gain, as determined electromyographically, was essentially obliterated by paralysis during epidural anesthesia, decreasing from -0.73 +/- 0.85 to -0.04 +/- 0.06 intensity units/degrees C (P < 0.01). However, upper-body gain had no compensatory increase: -1.3 +/- 1.1 units/degrees C control versus 2.0 +/- 2.1 units/degrees C epidural. Maximum oxygen consumption was decreased by one third during epidural anesthesia: 607 +/- 82 versus 412 +/- 50 ml/min (P < 0.05).These results confirm that regional anesthesia reduces the shivering threshold. Epidural anesthesia reduced the gain of shivering by 63% because upper-body muscles failed to compensate for lower-body paralysis. The thermoregulatory system thus fails to recognize that regional anesthesia reduces metabolic heat production, instead responding as if lower-body muscular activity remained intact.

    View details for Web of Science ID 000073024700002

    View details for PubMedID 9579491

  • Postanesthetic vasoconstriction slows peripheral-to-core transfer of cutaneous heat, thereby isolating the core thermal compartment ANESTHESIA AND ANALGESIA Plattner, O., Ikeda, T., Sessler, D. I., Christensen, R., Turakhia, M. 1997; 85 (4): 899-906


    Forced-air warming during anesthesia increases core temperature comparably with and without thermoregulatory vasoconstriction. In contrast, postoperative forced-air warming may be no more effective than passive insulation. Nonthermoregulatory anesthesia-induced vasodilation may thus influence heat transfer. We compared postanesthetic core rewarming rates in volunteers given cotton blankets or forced air. Additionally, we compared increases in peripheral and core heat contents in the postanesthetic period with data previously acquired during anesthesia to determine how much vasomotion alters intercompartmental heat transfer. Six men were anesthetized and cooled passively until their core temperatures reached 34 degrees C. Anesthesia was then discontinued, and shivering was prevented by giving meperidine. On one day, the volunteers were covered with warmed blankets for 2 h; on the other, volunteers were warmed with forced air. Peripheral tissue heat contents were determined from intramuscular and skin thermocouples. Predicted changes in core temperature were calculated assuming that increases in body heat content were evenly distributed. Predicted changes were thus those that would be expected if vasomotor activity did not impair peripheral-to-core transfer of applied heat. These results were compared with those obtained previously in a similar study of anesthetized volunteers. Body heat content increased 159 +/- 35 kcal (mean +/- SD) more during forced-air than during blanket warming (P < 0.001). Both peripheral and core temperatures increased significantly faster during active warming: 3.3 +/- 0.7 degrees C and 1.1 +/- 0.4 degrees C, respectively. Nonetheless, predicted core temperature increase during forced-air warming exceeded the actual temperature increase by 0.8 +/- 0.3 degree C (P < 0.001). Vasoconstriction thus isolated core tissues from heat applied to the periphery, with the result that core heat content increased 32 +/- 12 kcal less than expected after 2 h of forced-air warming (P < 0.001). In contrast, predicted and actual core temperatures differed only slightly in the anesthetized volunteers previously studied. In contrast to four previous studies, our results indicate that forced-air warming increases core temperature faster than warm blankets. Postanesthetic vasoconstriction nonetheless impeded peripheral-to-core heat transfer, with the result that core temperatures in the two groups differed less than might be expected based on systemic heat balance estimates. Implications: Comparing intercompartmental heat flow in our previous and current studies suggests that anesthetic-induced vasodilation influences intercompartmental heat transfer and distribution of body heat more than thermoregulatory shunt vasomotion.

    View details for Web of Science ID A1997XY23200034

    View details for PubMedID 9322477

  • Rapid core-to-peripheral tissue heat transfer during cutaneous cooling ANESTHESIA AND ANALGESIA Plattner, O., Xiong, J. Y., Sessler, D. I., Schmied, H., Christensen, R., Turakhia, M., Dechert, M., Clough, D. 1996; 82 (5): 925-930


    Perioperative thermal manipulations are usually directed at the skin surface because methods of directly warming the core are invasive or ineffective. However, inadequate heat flow between peripheral and core compartments will decrease the rate at which core temperature changes. We therefore determined whether core hypothermia is delayed after initiation of surface cooling. Six volunteers were anesthetized with propofol and midazolam, and maintained under three layers of passive insulation for 2.5-4 h. Subsequently, the skin surface was cooled using forced air, 1000 L/min, at 10 degrees C. Isoflurane was added as necessary to maintain arteriovenous shunt vasodilation. Overall heat balance was determined from the difference between cutaneous heat loss (thermal flux transducers) and metabolic heat production (oxygen consumption). Average arm and leg (peripheral) tissue temperatures were determined from 19 intramuscular needle thermocouples, 10 skin temperatures, and "deep" foot temperature. Overall body heat content decreased approximately 234 kcal during 2.5 h of active cooling. Core temperature, which was nearly constant before active cooling, decreased approximately 1.3 degrees C/h. There was no delay between initiation of active cooling and the decrease in core temperature. Furthermore, peripheral (arm and leg) and core (trunk and head) tissue heat contents decreased at virtually the same rates: approximately 50 kcal/h and approximately 47 kcal/h, respectively. These data indicate that there is little restriction of heat flow between peripheral and core tissues in vasodilated, anesthetized subjects.

    View details for Web of Science ID A1996UH19500006

    View details for PubMedID 8610900

Conference Proceedings

  • Clinical Reminders to Providers of Patients with Depressed Left Ventricular Ejection Fraction Increase Defibrillator Implantation: A Randomized Trial Gupta, A., Gholami, P., Turakhia, M., Friday, K., Heidenreich, P. LIPPINCOTT WILLIAMS & WILKINS. 2011
  • Atrial Mechanical Function Using Left Atrial Pressure Waveform Analysis in Persistent and Paroxysmal Atrial Fibrillation Patients Cheng, Z., Lo, R., Gupta, A., Perez, M., Zei, P., Hsia, H. H., Turakhia, M., Al-Ahmad, A., Wang, P. J. LIPPINCOTT WILLIAMS & WILKINS. 2009: S628-S628

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