Erwin Robin

A Comparative Study of Nitroglycerin and Propranolol

The action of sublingual nitroglycerin (0.6 mg) and intravenous propranolol (0.1 mg/kg) on shortening of right ventricular fibers was investigated in patients with and without coronary artery disease. This was accomplished with a newly devised strain gauge catheter. Hemodynamic parameters and changes in the oxidation-reduction potential of heart muscle were determined. Nitroglycerin results in decrease in shortening and velocity of shortening of ventricular fibers, heart rate, left ventricular end-diastolic and systemic pressure, dp/dt, tension-time index, stroke index, peripheral resistance, and left ventricular minute work in normal and arteriosclerotic subjects. Intravenous propranolol leads to a fall in velocity of shortening of myocardial fibers, heart rate, dp/dt, stroke index, and left ventricular minute work. However, there is an increase in tension-time index and peripheral resistance with no change in systemic pressure. Left ventricular end-diastolic pressure rises significantly in arteriosclerotic patients. The myocardial oxidation-reduction potential increases after nitroglycerin whereas it falls after propranolol in normal and arteriosclerotic patients.

Hemodynamic consequences of total removal of the tricuspid valve without prosthetic replacement

Tricuspid valvulectomy without prosthetic replacement has been advocated as a life-saving measure in the treatment of Pseudomonas endocarditis of the tricuspid valve. This report describes the hemodynamic data obtained in 10 patients before and after removal of the tricuspid valve. Seven patients remained free of carciac decompensation, but right heart failure developed in three. Analysis of the preoperative data did not permit differentiation of these two groups of patients.

Persistence of low cardiac output after relief of high output by thiamine in a case of alcoholic beriberi and cardiac myopathy

Abstract Physiologic observations on myocardial performance and coronary circulation were obtained in an alcoholic noncirrhotic subject with beriberi heart disease who developed low cardiac output failure shortly after successful treatment with thiamine. The initial cardiac study revealed biventricular failure, high cardiac index, low peripheral resistance, and increased coronary blood flow with a narrow myocardial arteriovenous oxygen difference. Neither exercise nor ouabain was effective in restoring circulatory dynamics toward normal. Thiamine improved myocardial function not only at rest, but also during exercise. During the state of low output failure, biventricular failure with low cardiac index and elevated peripheral resistance was observed. Coronary blood flow and myocardial oxygen consumption were normal. Exercise and thiamine were without effect; ouabain improved myocardial response to exercise.

The Effect of Glucagon on the Coronary Circulation in Man

Glucagon, 300 &mgr;g/ minute, was infused intravenously over 15 minutes in 27 subjects. The patients were divided into three groups: group I, patients without heart disease; group II, patients with arteriosclerotic heart disease; and group III, patients with congestive heart failure. Hemodynamic measurements included observations on myocardial blood flow using bolus injections of 84rubidium and a coincidence counting technic. Myocardial oxygen consumption was determined after coronary sinus intubation in nine of the 27 patients. Significant increases were noted in heart rate, mean arterial pressure, tension-time index/minute and left ventricular work. Myocardial blood flow increased significantly while myocardial oxygen extraction remained constant suggesting that the augmentation in blood flow was sufficient to meet the increased myocardial demands for oxygen. The effects of glucagon on the coronary circulation resemble that of isoproterenol rather than norepinephrine without, however, leading to the production of arrhythmias seen with these catecholamines.

Aortic origin of the left pulmonary artery

A case of tetralogy of Fallot with aortic origin of the left pulmonary artery is presented. This rare malformation should be suspected in a child with stunted growth, cyanosis, a continuous murmur over the pulmonary area and a hypervascular left lung on chest roentgenogram. Final diagnosis depends upon cardiac catheterization and angiocardiography. During surgical correction of the tetralogy, the left pulmonary artery can be divided from the aorta and anastomosed to the main pulmonary artery.

Correlation of Cold Pressor Response With Coronary Atherosclerosis and Left Ventricular Performance

A comparison of cold pressor response with coronary arteriography and left ventriculography was made in 26 consecutive patients having chest pain suggesting coronary heart disease. Patients with normal coronary arteriograms and normal left ventriculograms showed normal cold pressor responses. Patients with coronary atherosclerosis and normal left ventricular performance showed an exaggerated cold pressor response, whereas patients with severe coronary atherosclerosis and poor left ventricular performance did not exhibit an exaggerated cold pressor response. In patients with inferior wall myocardial infarction having dyskinesia or akinesia of the inferior wall, the cold pressor response was not impaired. In contrast, patients with anterior wall myocardial infarction and dyskinesia or akinesia of the anterior wall showed a marked impairment of the left ventricular performance and no exaggeration of the cold pressor response.