Henry Swan

Isolated Valvular Pulmonic Stenosis Clinical and Physiologic Response to Open Valvuloplasty

The preoperative and postoperative clinical and physiologic data are presented in 10 patients with isolated valvular pulmonic stenosis. The valvulotomy was performed in five patients by the generally accepted blind ventricular approach, while in the remaining five patients the valvular surgery was accomplished by a direct pulmonary arterial approach. The physiologic data revealed uniform obliteration of the systolic pressure gradient from the right ventricle to the pulmonary artery in the patients operated by the direct technic in striking contrast to the inadequate and variable relief of stenosis by the transventricular approach.

Prostigmine Inhibition of Ventricular Fibrillation in the Hypothermic Dog

This study shows that when prostigmine is given via coronary perfusion in the hypothermic dog, cardiac surgery can be performed without ventricular fibrillation resulting. This action of prostigmine seems to be due to an accumulation of acetylcholine, since prostigmines antifibrillatory action can be reproduced by a continuous coronary perfusion of acetylcholine or by stimulation of the vagus nerve. A possible relationship between potassium and ventricular fibrillation is discussed.

Posthypothermic Circulatory Failure I. Physiologic Observations on the Circulation

Certain aspects of cardiovascular function were studied in dogs that were cooled to 30 C. without ventilatory assistance, and rapidly rewarmed in warm water. While in the hypothermic state, the animals appeared to make an adequate cardiovascular adjustment to the lowered body temperature. Upon rewarming, however, each animal incurred an acute circulatory collapse, which was characterized by a low cardiac output, diminished ventricular work, hypotension, hyperpnea, and increased arteriovenous oxygen difference. It is uncertain whether this circulatory failure is central or peripheral in origin.

Valvular Pulmonary Stenosis with Intact Ventricular Septum Clinical and Physiologic Response to Open Valvuloplasty

Clinical and physiologic studies have been carried out in 25 patients following surgical correction of congenital valvular pulmonary stenosis. The patients were operated upon under conditions of hypothermia and circulatory occlusion and the approach to the valve was transarterial, permitting plastic repair of the stenotic pulmonary valve with unimpaired vision and a dry operative field. The systolic pressure gradient between the right ventricle and the pulmonary artery has been completely abolished in 17 of the 25 patients. The results as reported in this series are considered to be superior to those obtained with the blind transventricular approach and the operative mortality certainly compares favorably with the transventricular approach.

Atrial Septal Defect: Clinical and Physiologic Response to Complete Closure in Five Patients

Complete surgical closure of an atrial septal defect was accomplished under direct vision in five patients. Postoperative catheterization studies demonstrated complete obliteration of the previously existing left-to-right shunt and a reduction of the pulmonary artery blood pressure in all patients. The clinical and hemodynamic status returned to normal limits with but few exceptions.

Traumatic Aortic Aneurysms

Aneurysm of the thoracic aorta may follow severe, nonpenetrating injuries of the thorax unaccompanied by rib fractures. The aneurysms characteristically appear in the first portion of the descending aorta or less commonly in the proximal ascending portion. A large aneurysm, progressive enlargement, or symptoms may necessitate excision or repair. Such repair is now feasible. Traumatic aortic aneurysm should be considered in the differential diagnosis of obscure lesions in the thorax when there is a history of severe antecedent trauma.

Tricuspid stenosis: Clinical and physiologic evaluation☆

Abstract The patients presented at this time demonstrate that the association of mitral stenosis with tricuspid valve disease represents an operable state. Thoughtful consideration of the history and careful physical examination will usually indicate the presence of tricuspid disease. Hemodynamic studies in such patients, with attention to the atrioventricular pressure gradient in early diastole, will aid in arriving at a decision regarding the operability of the tricuspid lesion. The operative mortality and morbidity are high in this type of patient but the probability of improvement warrants operative therapy.

Effect of Coronary Perfusion of Prostigmine on Ventricular Fibrillation in the Hypothermic Dog.

Summary Prostigmine is shown to have an antifibrillatory effect in the hypothermic dog. This agent is more effective when given by coronary perfusion than when given intravenously. When ventricular fibrillation occurs in the unprotected animal, coronary perfusion of prostigmine will allow conversion to a normal rhythm by massage and electric shock. It is felt that the antifibrillatory effect of prostigmine is probably due to an accumulation of acetylcholine.

Hypothermia for General and Cardiac Surgery: With Techniques of Some Open Intracardiac Procedures Under Hypothermia

FOR many years there have been sporadic attempts to explore the value of lowering body temperature as a therapeutic modality. Recently, interest has been rekindled in the subject because of its potential use as a technique for prolonging the safe period of circulatory occlusion, thus protecting tissue viability during operative intervention in a bloodless field. Of particular appeal was this potential as a technique for operation within the open heart during temporary occlusion of circulation. Enough experience, both laboratory and clinical, has now been accumulated to show that the method of general hypothermia can be applied to man at reasonable risk for a variety of operative purposes. This report is primarily concerned with the technique and risks of hypothermia and with new direct vision cardiac operations, the development of which has been made possible by hypothermia. .

Aminosulfonic acid buffer preserves myocardium during prolonged ischemia

Prevention of myocardial acidosis during global ischemia in operative cardiopreservation was explored in two series of dogs where acid-base control was the only variable. A specifically designed aminosulfonic acid buffer composition, 3:1 molar equivalents NaMOPS to HEPES, 0.2 mol/L, was compared with NaHCO3 (pH 8). Dissolved in standard cardioplegic solution it was given every 30 minutes by coronary infusion at 20 degrees C during 3 hours of global ischemia. Glass electrode intramyocardial pH, adenosine triphosphate (ATP) level, left ventricular contractility (Dp/Dt) and compliance (-Dp/Dt), and other cardiovascular parameters were measured frequently throughout ischemia and for 75 minutes thereafter. In the buffer group (n = 6) myocardial pH remained above entry levels throughout the study period, adenosine triphosphate level remained normal during ischemia, and Dp/Dt and -Dp/Dt at 75 minutes of reperfusion were above entry levels. In the NaHCO3 group (n = 6) pH declined and remained depressed throughout ischemia, adenosine triphosphate level fell steadily and significantly throughout the experiment, and Dp/Dt and -Dp/Dt never regained entry levels. The difference in each parameter between the two groups was statistically significant (p < 0.05). We conclude that control of myocardial acid-base equilibrium alone during global ischemia will preserve myocardial function and minimize reperfusion injury.