Bio

Clinical Focus


  • Pediatric Cardiology
  • Pediatric Electrophysiology

Academic Appointments


Professional Education


  • Fellowship:Stanford Hospital and Clinics-Room HC 435 (2011) CA
  • Board Certification: Pediatrics, American Board of Pediatrics (2007)
  • Medical Education:Albert Einstein College of Medicine (2004) NY
  • Residency:Children's Hospital Los Angeles (2007) CA
  • Board Certification: Pediatric Cardiology, American Board of Pediatrics (2010)
  • Internship:Children's Hospital Los Angeles (2005) CA

Publications

Journal Articles


  • In-hospital arrhythmia development and outcomes in pediatric patients with acute myocarditis. American journal of cardiology Miyake, C. Y., Teele, S. A., Chen, L., Motonaga, K. S., Dubin, A. M., Balasubramanian, S., Balise, R. R., Rosenthal, D. N., Alexander, M. E., Walsh, E. P., Mah, D. Y. 2014; 113 (3): 535-540

    Abstract

    Cardiac arrhythmias are a complication of myocarditis. There are no large studies of in-hospital arrhythmia development and outcomes in pediatric patients with acute myocarditis. This was a retrospective 2-center review of patients ≤21 years hospitalized with acute myocarditis from 1996 to 2012. Fulminant myocarditis was defined as the need for inotropic support within 24 hours of presentation. Acute arrhythmias occurred at presentation and subacute after admission. Eighty-five patients (59% men) presented at a median age of 10 years (1 day to 18 years). Arrhythmias occurred in 38 patients (45%): 16 acute, 12 subacute, and 9 acute and subacute (1 onset unknown). Arrhythmias were associated with low voltages on the electrocardiogram (14 of 34, 41% vs 6 of 47, 13%; odds ratio [OR] 4.78, 95% confidence interval [CI] 1.60 to 14.31) and worse outcome (mechanical support, orthotopic heart transplant, or death; OR 7.59, 95% CI 2.61 to 22.07) but were not statistically significantly associated with a fulminant course, ST changes, initial myocardial function, lactate, creatinine level, C-reactive protein and/or erythrocyte sedimentation rate, or troponin I level, after adjusting for multiple comparisons. Subacute arrhythmias were associated with preceding ST changes (10 of 15, 67% vs 15 of 59, 25%, OR 5.87, 95% CI 1.73 to 19.93). All patients surviving to discharge had arrhythmia resolution or control before discharge (10 on antiarrhythmic), with 1 exception (patient with complete heart block requiring a pacemaker). At 1-year follow-up, there were 3 recurrences of ventricular arrhythmias, but no arrhythmia-related mortality. In conclusion, arrhythmias are common in pediatric patients with myocarditis, occurring in nearly 1/2 of all hospitalized children and are associated with a worse outcome. Early identification of subacute arrhythmias using electrocardiographic changes may help management. A majority of patients do not require continued postdischarge arrhythmia treatment.

    View details for DOI 10.1016/j.amjcard.2013.10.021

    View details for PubMedID 24332245

  • Electrophysiologic therapeutics in heart failure in adult congenital heart disease. Heart failure clinics Motonaga, K. S., Khairy, P., Dubin, A. M. 2014; 10 (1): 69-89

    Abstract

    Arrhythmias have long been recognized as a major cause of morbidity and mortality in the adult with congenital heart disease. It is important that the clinician accurately diagnoses these disturbances and is cognizant of the full array of antiarrhythmic agents and devices available to treat these conditions. This review discusses the most common arrhythmias encountered in this population and the therapeutic options available. Specific issues unique to this population are also addressed.

    View details for DOI 10.1016/j.hfc.2013.09.011

    View details for PubMedID 24275296

  • Diagnosis and Management of Pediatric Brugada Syndrome: A Survey of Pediatric Electrophysiologists. Pacing and clinical electrophysiology : PACE Harris, B. U., Miyake, C. Y., Motonaga, K. S., Dubin, A. M. 2014

    Abstract

    Brugada syndrome (BrS) can be difficult to diagnose and treat, especially in the young patient. As there is currently no consensus on the evaluation and treatment of BrS in the pediatric population, we sought to describe the current practice for the diagnosis and treatment of BrS among pediatric electrophysiologists.A web-based survey was distributed to 204 physician members (MDs) of The Pediatric and Adult Congenital Electrophysiology Society (PACES). Practice characteristics, BrS patient attributes, and diagnostic and therapeutic preferences were collected.Responses were obtained from 83 pediatric electrophysiologists. The most common initial presentation was family history. There is a large variation in testing, particularly in the use of electrophysiology (EP) studies, drug challenge testing, and genetic testing. Despite limited treatment options, there is only consensus in the therapeutic approach to the pediatric patient with symptomatic BrS with 97% of physicians recommending an implantable cardioverter defibrillator (ICD). In the asymptomatic patient, a wide variation in therapy was seen with only 27% of physicians recommending an ICD CONCLUSIONS: Significant practice variation exists among pediatric electrophysiologists with deviation from accepted diagnostic and therapeutic practices for adult BrS patients. Further studies are necessary to establish best practice guidelines for BrS in the pediatric EP community.

    View details for DOI 10.1111/pace.12346

    View details for PubMedID 24456371

  • Do pediatric electrophysiologists read pre-participation screening electrocardiograms more accurately than general pediatric cardiologists? journal of pediatrics Harbison, A. L., Hill, A. C., Motonaga, K. S., Miyake, C. Y., Dubin, A. M. 2013; 163 (6): 1775-1777

    Abstract

    Pre-participation electrocardiogram (ECG) screening of athletes is controversial. Pediatric electrophysiologists do not interpret screening ECGs more accurately than pediatric cardiologists with average number of correct ECG interpretations of 13.1-12.4 (P = .14). Electrophysiologists ordered fewer follow-up tests and were more likely to give sports recommendations based on published guidelines.

    View details for DOI 10.1016/j.jpeds.2013.07.034

    View details for PubMedID 23993128

  • The effects of ketamine on dexmedetomidine-induced electrophysiologic changes in children. Paediatric anaesthesia Char, D., Drover, D. R., Motonaga, K. S., Gupta, S., Miyake, C. Y., Dubin, A. M., Hammer, G. B. 2013; 23 (10): 898-905

    Abstract

    BACKGROUND: Dexmedetomidine is an alpha2-adrenergic agonist used for sedation and analgesia in children. We previously showed that dexmedetomidine depresses sinus and AV nodal function resulting in adverse hemodynamic effects such as bradycardia and increased blood pressure. We hypothesized that these effects of dexmedetomidine might be antagonized by co-administration of ketamine, which has sympathomimetic properties. METHODS: Twenty-two children (ages 5-17 years) undergoing electrophysiologic (EP) study and ablation for supraventricular tachycardia were enrolled. Patients were kept sedated with continuous infusion of propofol at a fixed rate. Hemodynamic and EP parameters were measured before and after a loading dose of dexmedetomidine (1 μg·kg(-1) ). A continuous infusion of dexmedetomidine (0.7 μg·kg(-1) ·h(-1) ) was initiated and a ketamine loading dose (1 mg·kg(-1) ), followed by continuous infusion (1 mg·kg(-1) ·h(-1) ), was given. A repeat set of hemodynamic and EP parameters were then measured at the time of projected peak tissue concentration for both drugs. RESULTS: A significant increase in mean arterial pressure (MAP) was seen compared with baseline after loading of dexmedetomidine. This returned to baseline after co-administration of ketamine (mean difference between baseline and after ketamine 1.8 mmHg; 95%CI, -7.8 to 4.3; P = <0.001). A decrease in heart rate was seen after dexmedetomidine followed by a return to baseline after co-administration of ketamine (mean difference between baseline and after ketamine -6.5 bpm; 95%CI, -11.2 to -1.8; P = 0.005). Sinus node recovery time was lengthened after dexmedetomidine but returned to baseline after ketamine (mean difference between baseline and after ketamine -16.2 ms; 95%CI, -63 to 30; P = 0.014). QT was prolonged after dexmedetomidine and returned to baseline after ketamine (mean difference between baseline and after ketamine -34.2 ms; 95%CI, -48.4 to -20.2; P = 0.004). AV nodal effective refractory period was also impaired after dexmedetomidine and showed weak evidence for return to baseline function after ketamine (mean difference between baseline and after ketamine -22.8 ms; 95%CI, -40.2 to -5.2; P = 0.069). CONCLUSION: The concurrent use of ketamine may mitigate the negative chronotropic effects of dexmedetomidine.

    View details for DOI 10.1111/pan.12143

    View details for PubMedID 23506472

  • Infant Ventricular Fibrillation After ST-Segment Changes and QRS Widening: A New Cause of Sudden Infant Death? Circulation. Arrhythmia and electrophysiology Miyake, C. Y., Davis, A. M., Motonaga, K. S., Dubin, A. M., Berul, C. I., Cecchin, F. 2013; 6 (4): 712-718

    Abstract

    BACKGROUND: -Ventricular arrhythmia related sudden cardiac arrest in infants with structurally normal hearts is rare. There have been no previously published reports of infants less than 3 months of age with ventricular fibrillation in which a primary diagnosis could not be defined. METHODS AND RESULTS: -Retrospective chart review of 3 unrelated infants less than 2 months of age from 3 different tertiary care centers within the United States and Australia. All 3 infants survived sudden cardiac arrest secondary to multiple episodes of polymorphic ventricular tachycardia and ventricular fibrillation. Each infant demonstrated unique and transient ECG findings consisting of ST changes and QRS widening prior to arrhythmia onset that have not been previously reported. Amiodarone, sedation, sodium channel blocking agents and/or ventricular pacing were effective in suppressing acute events. Despite thorough investigation including genetic testing, the etiology of the ventricular arrhythmias in each of these infants remains unclear. CONCLUSIONS: -This is the first report of idiopathic ventricular fibrillation in young infants preceded by stereotypical transient ECG changes. These findings may represent a new, potentially treatable cause of sudden infant death. Recognition of these prodromal changes may be important in future management and survival of these infants.

    View details for DOI 10.1161/CIRCEP.113.000444

    View details for PubMedID 23748209

  • Insights into dyssynchrony in Hypoplastic Left Heart Syndrome HEART RHYTHM Motonaga, K. S., Miyake, C. Y., Punn, R., Rosenthal, D. N., Dubin, A. M. 2012; 9 (12): 2010-2015

    Abstract

    Cardiac resynchronization therapy has been proposed for treatment of hypoplastic left heart syndrome (HLHS) patients with right ventricular (RV) failure. The role of dyssynchrony, however, is poorly understood in this population.The purpose of this study was to better understand the relationship between electrical and mechanical dyssynchrony in HLHS using 3-dimensional electrical mapping, tissue Doppler indices of wall motion, and vector velocity imaging.Eleven HLHS subjects with normal RV function and ten normal subjects (age 3-18 years) were studied. Electrical and mechanical activation times and dyssynchrony indices (electrical dyssynchrony index, mechanical dyssynchrony index) were calculated using 3-dimensional electrical mapping, tissue Doppler indices, and vector velocity imaging.No differences in measures of electrical dyssynchrony were seen when comparing HLHS patients and normal patients (electrical activation time 63.3 ± 22.8 ms vs 56.2 ± 11.2 ms, P = .38; electrical dyssynchrony index 13.7 ± 6.3 ms vs 11.6 ± 3.0 ms, P = .34). However, measures of mechanical dyssynchrony were markedly abnormal in HLHS patients despite normal RV function (mechanical activation time 16 ± 11.3 ms vs 0.9±1.9 ms, P = .01; mechanical dyssynchrony index 7.5 ± 5.5 vs 0.4 ± 0.8, P<.01).Patients with HLHS and preserved RV systolic function have normal electrical activation when compared to patients with normal right and left ventricles. In contrast, these patients demonstrate mechanical dyssynchrony compared to patients with normal right and left ventricles. This finding raises important questions about the indications for cardiac resynchronization therapy in this patient population.

    View details for DOI 10.1016/j.hrthm.2012.08.031

    View details for Web of Science ID 000311791900029

    View details for PubMedID 23085485

  • Are wide complex tachycardia algorithms applicable in children and patients with congenital heart disease? JOURNAL OF ELECTROCARDIOLOGY Ceresnak, S. R., Liberman, L., Avasarala, K., Tanel, R., Motonaga, K. S., Dubin, A. M. 2010; 43 (6): 694-700

    Abstract

    Several algorithms have been developed to help determine the etiology of wide complex tachycardias (WCTs) in adults. Sensitivity and specificity for differentiating supraventricular tachycardia (SVT) with aberration from ventricular tachycardia (VT) in adults have been demonstrated to be as high as 98% and 97%. These algorithms have not been tested in the pediatric population. We hypothesize that these algorithms have lower diagnostic accuracy in children and patients with congenital heart disease.A retrospective review of the pediatric electrophysiology database at Stanford from 2001 to 2008 was performed. All children with WCT, a 12-lead electrocardiogram (ECG) available for review, and an electrophysiology study confirming the etiology of the rhythm were included. Patients with a paced rhythm were excluded. The ECGs were analyzed by 2 electrophysiologists blinded to the diagnosis according to the algorithms described in Brugada et al,(2) and Vereckei et al.(5) Additional ECG findings were recorded by each electrophysiologist.A total of 65 WCT ECGs in 58 patients were identified. Supraventricular tachycardia was noted in 62% (40/65) and VT in 38% (25/65) of the ECGs. The mean age was 13.5 years (SD ± 5.1), the mean weight was 51.8 kg (SD ± 22.4), and 48% (31/65) were male. The mean tachycardia cycle length was 340 milliseconds (SD ± 95). Congenital heart disease (CHD) was present in 37% (24/65) of patients (7 tetralogy of Fallot, 6 Ebstein's, 4 double-outlet right ventricle, 3 complex CHD, 2 d-transposition of great arteries, 1 status-post orthotopic heart transplantation, 1 ventricular septal defect). The Brugada algorithm correctly predicted the diagnosis 69% (45/65) of the time, the Vereckei algorithm correctly predicted the diagnosis 66% (43/65) of the time, and the blinded reviewer correctly predicted the diagnosis 78% (51/65) of the time. There was no difference in the efficacy of the algorithms in patients with CHD vs those with structurally normal hearts. The findings of left superior axis deviation (P < .01) and a notch in the QRS downstroke of V(1) or V(2) (P < .01) were more common in VT than SVT, whereas a positive QRS deflection in V(1) (P = .03) was more commonly present in SVT than VT.The Brugada and Vereckei algorithms have lower diagnostic accuracy in the pediatric population and in patients with congenital heart disease than in the adult population. Left superior axis deviation and a notch in the QRS downstroke were more commonly associated with VT, whereas a positive QRS deflection in V(1) was more commonly associated with SVT in this population.

    View details for DOI 10.1016/j.jelectrocard.2010.02.008

    View details for Web of Science ID 000284514700039

    View details for PubMedID 20382398

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