Prognosis of patients permanently paced for sick sinus syndrome.

In 39 patients (mean age, 66 years) treated for sick sinus syndrome (SSS) with pacemaker insertion, the long-term prognosis was studied. Fifteen patients (42%) died during the follow-up period of 6 to 59 months (mean, 25 months). Three patients were unavailable for follow-up. Eleven of the 15 deaths (73%) were cardiac-related, yet none could be associated with either an arrhythmia or pacemaker failure. Symptoms recurred or persisted after pacemaker insertion in 14 patients (mean age, 71 years), nine of whom died (31 deaths per 100 patient follow-up years). Twenty-two patients (mean age, 63 years) were asymptomatic after pacer insertion, six of whom died (11 deaths per 100 patient follow-up years). These follow-up results demonstrate a poor long-term prognosis in patients with SSS and persistent symptoms following permanent pacing.

Thallium-201 myocardial perfusion studies in patients with the mitral valve prolapse syndrome.

To determine whether regional myocardial ischemia plays a role in patients with the mitral valve prolapse syndrome, we examined myocardial perfusion with exercise stress testing and thallium-201 myocardial scintigraphy. Twelve patients were studied, 11 women and one man aged 18 to 56 years, mean age 30 years. In all patients, mitral valve prolapse was documented by echocardiography or phonocardiography. Patients over 35 years of age underwent cardiac catheterization. Electrocardograms disclosed abnormalities during maximal exercise in eight of the 12 patients. In two patients, angina developed during exercise. Thallium-201 (201Tl) scintigrams were normal in the 11 patients with presumed or documented normal coronary arteries. One patient, in whom an apical defect was demonstrated on scintigraphy, had significant disease of the left main and left anterior descending coronary artery. Repeat testing after successful aortocoronary bypass grafting revealed improved exercise capacity and a normal 201Tl myocardial scintigram. The data indicate that patients with mitral valve prolapse alone do not have regional myocardial ischemia and that the presence of a defect on 201Tl myocardial scintigraphy following maximal stress testing would suggest the existence of concomitant coronary artery disease.

Pharmacology of Sch 11973, N-(2-phenylisopropyl)-N-p-toluene sulfonyl urea, a potential new antianginal agent.

Antianginal drugs were evaluated on the basis of their ability to protect against subepicardial electrogram changes induced by local ventricular ischemia in anesthetized dogs. Sch 11973 [N-(2-phenylisopropyl)-N-p-toluene sulfonyl urea], a potential new antianginal agent, was also effective against local ventricular ischemia with its maximum effect appearing at 1mg/kg, i.v. or i.d. and with a duration of at least 2 hours. Nitroglycerin, at a dose of 0.04 mg/kg given bucally, exerted less protection, lasting on the average less than 15 minutes. Protection by propranolol at 1 mg/kg, i.v., was not better than nitroglycerin, but lasted up to one hour, while dipyridamole was ineffective when given in a dose range of 0.1-10 mg/kg, i.v. Sch 11973 differed from standard antianginal agents which may act via beta-adrenergic blocking activity or alteration of cardiac or circulatory dynamics since no acute pharmacological changes were observed after Sch 11973 was administered.

Cardiovascular function during early recovery from acute myocardial infarction.

Fifty patients with acute myocardial infarction were studied serially to evaluate the extent and nature of functional cardiovascular impairment and the time course of recovery. Reinfarction or death occurred in six patients. Peak workload during bicycle exercise in a subgroup of 25 patients with maximal initial test and complete follow-up increased from 334 to 409 kpm/min (P less than 0.01) bwtween three and six weeks. There was further significant (P less than 0.01) improvement between three and six months from 438 to 488 kpm/min. The incidence of ischemia at a constant workload decreased between three and six weeks without any significant changes in heart rate or blood pressure. Mean cardiac output during exercise at three months was 6.5 and at six months 7.8 L/min (P less than 0.05). Corresponding values for stroke volume were 61 and 72 ml (P less than 0.05). The data suggest that in clinically stable patients there is an early improvement of the relation between myocardial oxygen supply and demand and a late improvement of functional capacity associated with increased stroke volume and cardiac output.