Publications

All Publications


  • A NEW METHOD FOR ASSESSING RIGHT-SIDED HEART PRESSURES USING ENCAPSULATED MICROBUBBLES - A PRELIMINARY-REPORT WESTERN JOURNAL OF MEDICINE Oesterle, S., SAHINES, T., Tucker, C., TICKNER, E. G., RASOR, J., Kernoff, R., KANTROWITZ, N., Billingham, M., Wagner, L., Popp, R. L. 1985; 143 (4): 463-468

    Abstract

    A new noncatheter method for measuring pressures of the right side of the heart uses specially manufactured microbubbles of carbon dioxide injected into the peripheral venous system. Sudden expansion of these bubbles in the cardiac chambers causes bubble oscillations at a frequency that is primarily a function of surrounding pressure. The oscillations are recordable by a microphone on the chest wall. The preliminary experience has been in dogs and further development is needed before we can begin clinical testing of the method. In its current form, the potential for measuring higher systolic pressures seems better than that for lower diastolic pressures.

    View details for Web of Science ID A1985ASH4000001

    View details for PubMedID 3937336

  • ACUTE HEMODYNAMIC-EFFECTS OF INTRAVENOUS ENCAINIDE IN PATIENTS WITH HEART-DISEASE AMERICAN HEART JOURNAL Tucker, C. R., WINKLE, R. A., PETERS, F. A., HARRISON, D. C. 1982; 104 (2): 209-215

    Abstract

    Encainide, a new antiarrhythmic drug, was given intravenously (0.9 mg/kg) to 18 patients over 15 minutes to evaluate the hemodynamic effects. Hemodynamics and drug plasma concentrations were measured during and 30 minutes postdrug infusions. Encainide infusion was associated with a decrease in cardiac index from 2.6 +/- 0.7 to 2.4 +/- 0.7 L/min/m2 (p less than .05), a significant decrease in stroke work index and left ventricular end-diastolic pressure, and with a rise in systemic vascular resistance. There was no change in systemic or pulmonary arterial pressure, left ventricular dp/dt, or pulmonary vascular resistance. The patients were studied 30 to 60 minutes after cardiac angiography. Comparison of hemodynamic values obtained preangiography with those obtained postangiography (before, during, and after drug infusion) strongly suggests that many of the observed effects were due to radiographic contrast media (initial osmotic volume loading and subsequent diuresis). We conclude that if encainide has any significant hemodynamic effects after intravenous use, it is a modest decrease in cardiac output, possibly as a result of decreased left ventricular filling pressure.

    View details for Web of Science ID A1982PC02300005

    View details for PubMedID 6808816

  • TWO-DIMENSIONAL ECHOCARDIOGRAPHIC ANALYSIS OF SEGMENTAL LEFT-VENTRICULAR WALL MOTION BEFORE AND AFTER CORONARY-ARTERY BYPASS-SURGERY CIRCULATION Rubenson, D. S., Tucker, C. R., London, E., Miller, D. C., Stinson, E. B., Popp, R. L. 1982; 66 (5): 1025-1035

    Abstract

    Twenty patients with coronary artery disease were studied with two-dimensional echocardiography the day before saphenous vein bypass graft surgery. Serial studies were obtained 7.4 +/- 2.5 (+/- SD) and 43.4 +/- 13.1 days postoperatively to qualitatively assess the effect of bypass surgery on regional wall motion. Changes in segmental wall motion were assessed semiquantitatively by assigning a segmental wall motion score to each of nine echocardiographically defined segments. Preoperatively, 18% of the segments moved abnormally. The mean overall segmental wall motion score did not change significantly, as shown by comparing the postoperative studies with the preoperative study. However, there was a significant worsening in the septal motion (apical and basal) and a significant improvement in posterior wall motion (apical and basal) after bypass surgery. Anterior and lateral wall motion were not significantly changed. Nonseptal segments that were normal preoperatively usually remained normal; abnormal nonseptal segments usually improved or were unchanged by surgery. The motion of septal segments, however, generally worsened postoperatively whether they were normal or abnormal preoperatively. We conclude that segmental wall motion assessed by two-dimensional echocardiography may improve after revascularization surgery, but the interventricular septum shows impaired motion. This effect of coronary artery bypass on wall motion is better demonstrated relatively late after operation than early in the postoperative course, as has been done in some previous studies.

    View details for Web of Science ID A1982PM98800018

    View details for PubMedID 6982113

  • AORTITIS IN ANKYLOSING-SPONDYLITIS - EARLY DETECTION OF AORTIC ROOT ABNORMALITIES WITH 2 DIMENSIONAL ECHOCARDIOGRAPHY AMERICAN JOURNAL OF CARDIOLOGY Tucker, C. R., Fowles, R. E., Calin, A., Popp, R. L. 1982; 49 (4): 680-686

    Abstract

    Mild aortic root dilatation, cusp thickening and subvalvular fibrous ridges have been reported as characteristic in patients with ankylosing spondylitis and aortic regurgitation. Thirty-five patients with ankylosing spondylitis (10 also had Reiter's syndrome) without clinically apparent cardiac involvement were studied using phased array two dimensional and sector-directed M mode echocardiography to determine the prevalence of aortic abnormalities. Aortic root dimensions were measured at the aortic anulus, at the tip of the cusps and 0.5 to 1.5 cm above the cusps. The two dimensional echocardiographic study was also analyzed for qualitative abnormalities. The dimensions were compared with those in 20 normal men and among patient subgroups separated according to age, duration and severity of ankylosing spondylitis and presence of qualitative abnormalities. With one exception, no abnormally increased aortic dimensions suggestive of aortic dilatation were found in any group. However, two patients had aortic dimensions greater than 4.2 cm at the valve (normal 4.0 cm or less). Also, six patients had discrete areas of increased bright echoes below the left or noncoronary cusps suggestive of a subaortic "bump" and two of the six patients had increased aortic cusp echoes suggestive of thickening or fibrosis, or both. These changes tended to occur more commonly in older patients and those with more severe disease. It is concluded that aortic root changes suggestive of inflammation or fibrosis, or both, occur in asymptomatic patients with ankylosing spondylitis and are detectable on two dimensional echocardiography. Dilatation usually does not occur without aortic regurgitation.

    View details for Web of Science ID A1982NF97900007

    View details for PubMedID 7064818

  • CLINICAL-PHARMACOLOGY AND ANTI-ARRHYTHMIC EFFICACY OF ENCAINIDE IN PATIENTS WITH CHRONIC VENTRICULAR ARRHYTHMIAS CIRCULATION WINKLE, R. A., Peters, F., Kates, R. E., Tucker, C., HARRISON, D. C. 1981; 64 (2): 290-296

    Abstract

    We determined the pharmacokinetics, efficacy and therapeutic plasma concentration of encainide, a new antiarrhythmic drug that affects His-Purkinje conduction but not ventricular refractoriness. Nine patients with frequent and complex premature ventricular complexes were studied in a 3-day double-blind protocol. Each day, each patient received 75 mg of i.v. or oral encainide or placebo. Frequent blood samples for encainide plasma concentration determination and continuous ambulatory ECGs were obtained. There was a marked intersubject variation in bioavailability (mean 42 +/- 24%, range 7.4-82%), clearance (13.2 +/- 5.6 ml/min/kg, range 3.75-22.1 ml/min/kg) and half-life (3.4 +/- 1.7 hours i.v., 2.5 +/- 0.8 hours oral). Eight of nine patients had more than 90% suppression of premature ventricular complexes for 3-36 hours. Minimal antiarrhythmic plasma concentration was higher (39 +/- 54 ng/ml, range 3.5-170 ng/ml) after i.v. dosing than after oral dosing (14 +/- 16 ng/ml, range 1.5-48 ng/ml), suggesting an active metabolite after oral dosing in many patients. Minimal side effects were seen despite high peak plasma concentrations (range 794-1556 ng/ml i.v., 36-495 ng/ml oral). The minimal ratio of toxic to therapeutic plasma concentration ranged from 4.3-326 (median 23) after oral dosing. Antiarrhythmic action was associated with an 11-44% widening of the QRS complex that was not associated with other adverse effects. We conclude that encainide effectively suppresses ventricular arrhythmias. Despite a variable bioavailability, high clearance and short half-life, its wide ratio of toxic to therapeutic concentration and probable active metabolite permit a long duration of action, which should allow a reasonable dose schedule in most patients during chronic oral dosing.

    View details for Web of Science ID A1981LZ32900010

    View details for PubMedID 6788400

  • THE USE OF ECHOCARDIOGRAPHY IN DIAGNOSING CULTURE-NEGATIVE ENDOCARDITIS CIRCULATION Rubenson, D. S., Tucker, C. R., Stinson, E. B., LONDON, E. J., Oyer, P., MORENOCABRAL, R., Popp, R. L. 1981; 64 (3): 641-646

    Abstract

    We reviewed M-mode and two-dimensional echocardiographic findings in 11 patients with abacteremic endocarditis to study the application of echocardiography in this setting. All patients had negative blood cultures but underwent surgery that confirmed the presence of active infective endocarditis. The infection involved native valves in five patients and prosthetic valves in six patients. Valvular masses were identified in eight patients. The other three patients, who had prosthetic aortic valves, had diastolic mitral valve vibration characteristic of aortic regurgitation. One of these also showed dehiscence of the prosthesis. Three patients had poorly defined clinical illnesses and echocardiography was a prime element in the diagnosis because valvular masses were identified. The operation was facilitated by knowledge of the mass indicated by echocardiography in these eight cases. Also, the surgical approach was affected by knowledge of dehiscence and perivalvular abscess formation in two cases each.

    View details for Web of Science ID A1981MB94200028

    View details for PubMedID 7020979

  • ECHOCARDIOGRAPHY - M-MODE AND TWO-DIMENSIONAL METHODS ANNALS OF INTERNAL MEDICINE Popp, R. L., Rubenson, D. S., Tucker, C. R., French, J. W. 1980; 93 (6): 844-856

    Abstract

    We review the basic similarities and differences of currently used M-mode and two-dimensional (2D) echocardiography. Discrete categories of disease are used to show the relative strengths of M-mode and 2D methods. The format of 2D echocardiography is well suited to analyze congenital heart disease, consequences of coronary artery disease, and distortions of anatomy due to acquired heart disease. Rapid structure movement is preserved with M-mode recording, facilitating detailed analysis of motion. The vast clinical experience with M-mode echocardiography can now be augmented by 2D echocardiography, but combination of 2D and M-mode methods is optimal for understanding each type of ultrasound recording and for best serving the patient.

    View details for Web of Science ID A1980KV10800018

    View details for PubMedID 7447194

Footer Links:

Stanford Medicine Resources: