Peter M. Yurchak

Clinical Spectrum of the Sick Sinus Syndrome

The clinical spectrum of the sick sinus syndrome (SSS) is described in a series of 56 patients who demonstrated either persistent unexplained sinus bradycardia (group I: eight patients); sinus arrest (group II: 15 patients); or bradycardia with episodic supraventricular tachyarrhythmias (group III: 33 patients). Coronary disease was the most common form of heart disease where etiology could be determined, but in 25 patients no clear etiologic diagnoses could be established. Thirty-three patients showed associated electrocardiographic conduction disturbances. Symptoms were common and were produced by both bradycardia and tachycardia. Eight patients in the bradycardia-tachycardia group experienced cerebral embolization. Despite bother-some symptoms, only six of the 56 patients died over an average follow-up of 7 years, and only one of these deaths appeared related to an arrhythmia. Drug therapy of bradycardia was generally ineffective, but digitalis was frequently helpful in patients with tachycardia. Electrical pacing was uniformly successful in treating symptoms of bradycardia but was disappointing in preventing tachyarrhythmias.

Thromboembolic Complications of Prosthetic Cardiac Valves

Our experience with thromboembolism in 283 patients surviving at least 1 week following insertion of Starr-Edwards valves is reported here. Of these patients, 155 underwent aortic valve replacement, 21 had aortic valve replacement with mitral commissurotomy, 80 had mitral replacement, and 27 had both aortic and mitral valve replacement. Complete follow-up data were obtained on all patients, from 3 to 49 months following surgery (mean, 20 months).Thromboembolic episodes developed in 68 of the 283 patients (24%). Seventeen of these 68 patients died (25%), three had serious neurological residual (4%), but the majority of survivors recovered completely.Use of long-term anticoagulant therapy appeared to reduce incidence of embolic episodes only in patients with aortic valve replacement. Control of anticoagulant therapy (good, fair, or poor) bore no relationship to incidence of embolism within this group. Anticoagulant therapy in untreated patients with emboli reduced the incidence of subsequent thromboembolism. Hemorrhagic complications occurred in 23 patients (8%); one died.Thromboembolism is a serious complication of prosthetic valves. Its incidence in some patients is reduced but not eliminated by anticoagulant therapy.

Reversible obstruction of the ventricular outflow tract.

Abstract Obstruction of the left ventricular outflow tract with characteristics of subaortic muscular hypertrophy has been produced in a human subject and 2 of 8 dogs by infusion of isoproterenol. In 2 other dogs with outflow tract gradients in the “control” state, infusion of blood relieved the obstruction. The possible role of adrenergic stress in producing the clinical disease and the relationship of both to the hyperkinetic heart syndrome are discussed.

Chronic Overdrive Pacing in the Control of Refractory Ventricular Arrhythmias

Abstract Eleven patients with recurrent ventricular tachycardia or ventricular fibrillation that was refractory to antiarrhythmic drugs were treated with long-term, overdrive atrial or ventricular ...

Heart Block in Polymyositis

POLYMYOSITIS is said rarely to involve the myocardium. Only two pathologically documented cases of polymyositis with myocardial involvement have been reported, and conduction disorders were noted i...

Recognition of digitalis intoxication in the presence of atrial fibrillation.

Excerpt There is no agent in the pharmacopeia so useful, yet so potentially hazardous, as digitalis. Lifesavingto thousands with heart failure, it has been life-endingto countless others in whom si...

EFFECTS OF NOREPINEPHRINE ON THE CORONARY CIRCULATION IN MAN.

The effect of norepinephrine infusion on the coronary circulation has been studied in 21 subjects. In doses ranging from 2 to 17 &mgr;g. base per minute norepinephrine caused a pari passu rise in perfusing pressure and coronary flow of 16 per cent above the control state. Despite an increase in cardiac oxygen consumption, coronary vascular resistance was unchanged, suggesting no vasodilatation in the coronary bed. On the contrary, oxygen extraction across the heart increased, implying that oxygen needs were inadequately met by rise in flow. An increase in vascular tone induced by norepinephrine is inferred from the unchanged coronary resistance at a higher perfusion pressure.Responses of the normal and failing left ventricle groups were qualitatively the same as for the group as a whole. The failure group showed greater tendency to meet oxygen needs by increased extraction than did the normal hearts.Although these observations are not strictly applicable to the role and effects of norepinephrine in states of clinical shock, nonetheless it seems likely that norepinephrine induces a suboptimal rise in coronary flow that may set the stage for ultimate myocardial ischemia, particularly when coronary perfusion pressure is inadequate.

Pressure-Volume Correlates of Left Ventricular Oxygen Consumption in the Hypervolemic Dog

Volume changes in the intact functioning canine left ventricle were induced by whole blood infusion and were measured by the thermodilution technic. Multiple regression analyses were performed to detect significant correlations between hemodynamic variables and left ventricular oxygen consumption. Hemodynamic variables, in addition to the pressure-time integral, ventricular volume, and ventricular work, included estimates of myocardial stress, force, and shortening. The most significant individual correlates of oxygen consumption were the pressure-time integral (r=0.91) and ventricular end systolic volume (r=0.81), whereas the interaction of volume with pressure-time, thus approximating wall stress and force, was the most significant variable overall (r=0.93). A number of multiple linear regression models were tested for the prediction of ventricular oxygen consumption. The equation (model E) with the greatest multiple regression coefficient (R=0.947) included heart rate, pressure-time per beat, pressure-time per minute, end systolic volume, and (end systolic volume)2/3 as independent variables. A less elaborate regression equation including only pressure-time per minute and end systolic volume as independent variables was, however, nearly as accurate as model E in the prediction of oxygen consumption. The addition of estimates of left ventricular work and shortening to these regression models did not further improve the ability to predict oxygen consumption accurately. The relationships between these hemodynamic variables and ventricular oxygen consumption were not altered by pericardiotomy or catecholamine depletion. In the hypervolumic heart acute ventricular dilatation did not occur following pericardiotomy. The results of this study confirm the postulate that an increase in ventricular volume, as well as pressure, will be accompanied by an increase in ventricular oxygen consumption. This in turn implies a relationship between the wall stress or force generated by the myocardium and the energy requirement of contraction.

Constrictive Pericarditis Complicating Disseminated Lupus Erythematosus

A case of constrictive pericarditis complicating disseminated lupus erythematosus is reported in a 58-year-old man. Hemodynamic studies documented the diagnosis and also confirmed the clinical suspicion of coexistent atrial septal defect. Measurement of left ventricular volume by a thermodilution technic augmented information available from routine studies. Pericardiectomy and closure of the atrial septal defect relieved the mechanical lesion.The case is also unique in its documentation of the coexistence of three different forms of heart disease—congenital atrial septal defect, pericardial constriction from lupus erythematosus, and rheumatic valvular disease.

Acute myocardial infarction after ergonovine administration for uterine bleeding

Abstract Acute myocardial infarction during pregnancy and in the postpartum period is a rare occurrence of uncertain etiology. 1 It has been reported in women with atherosclerotic coronary artery disease, diabetes mellitus and systemic hypertension. 2 In women with normal coronary angiograms, however, no clear and consistent etiology can be found. A few cases did involve patients receiving ergot derivatives, but the events were poorly documented and established only by retrospective association. We report a patient who sustained an acute myocardial infarction after receiving methylergonovine for excessive uterine bleeding after a first trimester spontaneous abortion. The cardiac event was promptly recognized and treated, resulting in a relatively benign postmyocardial infarction course.