Effect of depressed left ventricular function on hemodynamics of normal St. Jude Medical prosthesis in the aortic valve position.

To evaluate the effect of left ventricular (LV) dysfunction on Doppler-derived transprosthetic hemodynamic indexes in patients with normally functioning St. Jude aortic valve prostheses, 74 consecutive patients were studied. LV ejection fraction was assessed by using Simpson's biplane rule.

Role of exercise thallium 201 imaging in decision making.

This prospective study examined the impact of results of exercise thallium 201 imaging on the estimation of probability of coronary artery disease (CAD) and patient management among cardiologists and internists in our institution. Before exercise testing, the probability of CAD in the 100 patients enrolled in this study was considered low in 31, intermediate in 28, and high in 41 patients. The probability of CAD after exercise thallium imaging was different in four patients (10%) in the high group, 22 patients (79%) in the intermediate group, and three patients (10%) in the low group.

The special problems of the patient with a valvular prosthesis.

In essence, patients who have valve replacement have one disease replaced by another. Neither the mechanical nor the tissue valves available at present are free of complications. These complications include hemodynamic and hematologic abnormalities, intrinsic valve malfunction, infective endocarditis, arrhythmias, and congestive heart failure.

Tracking of atrial flutter during DDD pacing: another form of pacemaker-mediated tachycardia.

Two patients who had DDD pacemakers inserted for symptomatic sick sinus syndrome developed sustained upper-rate limit pacing. It was demonstrated in these two patients that pacemaker-mediated tachycardia was due to tracking of atrial flutter. DDD pacemakers should be used with caution in patients with the sick sinus syndrome and associated atrial tachyarrhythmias.

Electrophysiologic testing: clinical applications.

Electrophysiologic studies can be used in evaluating a large number of arrhythmias and conduction disturbances. These tests are extremely useful in the diagnosis and treatment of sick sinus syndrome, paroxysmal supraventricular tachycardias, atrial flutter, and AV conduction abnormalities. The decision to implant a permanent pacemaker in patients with a history of syncope also may be aided by the results of electrophysiologic studies.

What is optimal drug therapy in angina pectoris?

The treatment of classic angina pectoris must be carefully individualized, taking into account factors such as age, degree of disability, anatomic location and extent of lesions, ventricular function, and psychologic makeup of the patient. In some instances, early coronary bypass surgery is indicated. In other cases, a trial with full medical therapy is indicated and, if successful, medical management should be continued with careful, ongoing monitoring of the clinical course.

Effects of thiopental on tension development, action potential, and exchange of calcium and potassium in rabbit ventricular myocardium.

Thiopental in concentrations of 28 and 227 mumoles/liter reduced the tension developed by isolated rabbit ventricular myocardium by 50 and 80%, respectively. The effect was rapid, reversible, and independent of heart rate. Thiopental (227 mumoles/liter) inhibited influx and efflux of potassium to the same extent, so that no net gain or loss occurred.

Left ventricular end-diastolic pressure response to atrial pacing in idiopathic mitral valve prolapse.

The response of several parameters of left ventricular function to right atrial pacing was compared in 21 patients with idiopathic mitral valve prolapse and 10 normal patients. An inability to appropriately lower left ventricular end-diastolic pressure with increasing rates was demonstrated in the mitral valve prolapse group. This abnormality was not related to mitral regurgitation or factors other than ventricular performance per se.

T-wave abnormalities of intermittent left bundle-branch block.

Ischemia is traditionally considered a cause of intermittent left bundle-branch block (LBBB), and some patients have right precordial T-wave inversion in the normally conducted beats. Clinical correlates of T-wave abnormalities were examined in 46 consecutive patients with intermittent LBBB. Thirty-three patients (72%) had at least transient right precordial (V-14) T-wave inversion suggesting ischemia in normally conducted beats.

Ventricular extrastimulation in the mitral valve prolapse syndrome. Evidence for ventricular reentry.

Fourteen patients with mitral valve prolapse and essentially normal coronary arteries were evaluated for ventricular arrhythmias, utilizing programmed ventricular extrastimulation. Three were symptomatic with ventricular tachyarrhythmias. Application of appropriately timed ventricular extrasystoles initiated the tachyarrhythmias in these three patients.

Electrophysiologic effects of hydralazine on sinoatrial function in patients with sick sinus node syndrome.

The electrophysiologic effects of hydralazine were evaluated in nine hypertensive patients with sinoatrial dysfunction. Intravenous hydralazine, 0.15 mg/kg, caused no significant reduction in arterial blood pressure.

The "R-on-T" phenomenon: an update and critical review.

The "R-on-T phenomenon" is the superimposition of an ectopic beat on the T wave of a preceding beat. Early observations suggested that R-on-T was likely to initiate sustained ventricular tachyarrhythmias. More recent experimental and clinical observations suggest that R-on-T is not a critical determinant of primary ventricular fibrillation in acute myocardial infarction; represents few of the initiating beats of paroxysmal ventricular tachycardia; and represents at worst only a small risk in terms of sudden death.

Congenital coronary arteriovenous fistula: a diagnostic challenge.

This report describes a case of coronary arteriovenous (A-V) fistula involving both the right and the left coronary arteries. The venous component of the two circulations combines into a single channel that empties into the left ventricle just below the mitral valve.

Propranolol in mitral stenosis during sinus rhythm.

Patients with early symptomatic mitral stenosis usually suffer from pulmonary congestion on the basis of left atrial and pulmonary venous hypertension. They are often in sinus rhythm, and cardiac output is usually well maintained. Symptoms occur most often when heart rate, cardiac output, or both are increased.

Postextrasystolic T wave changes and angiographic coronary disease.

The significance of postextrasystolic T wave changes in beats following induced extrasystoles was assessed by angiography in 55 patients. These T wave changes were found in 81 per cent of coronary artery disease patients but also in 68 per cent of patients with normal coronary arteries (PNS). All patients with normal baseline electrocardiograms and normal coronary arteries showed postextrasystolic T wave changes.

Knotting of a flow-directed catheter about a cardiac structure.

An instance of knotting of a flow-directed catheter about an intracardiac structure, presumably part of the tricuspid valve apparatus, is described. Because of the patient's severe pulmonary disease, cardiac surgery to remove the catheter was contraindicated. The central portion of the catheter was allowed to remain in situ, without apparent ill effects over a 16 month period.

The extent of supernormal ventricular excitability in man.

The supernormal period is an interval of increased excitability found in Purkinje fibers and thought to discretely neighbor T wave termination. Thereafter, excitability is thought to be constant. We examined the extent of the supernormal period in normokalemic patients at normal heart rates, determining excitability in terms of threshold voltages required for right ventricular bipolar excitation at 10-30 sec msec intervals of diastole.

Sustained haemodynamic action of nitroglycerin ointment.

Intravenous vasodilators have been shown to improve the haemodynamic status of patients in congestive heart failure. However, neither intravenous nor sublingual preparations are suitable for chronic administration or use in ambulatory patients. In this study, nitroglycerin ointment bas administered to 11 patients in congestive heart failure.