Wednesday Morning, May 11, 1960

8:30 A.M. Business Meeting (Limited to Members) Napoleon Room

8:45 A.M. Scientific Session: REGULAR PROGRAM Napoleon Room

1. The Use of Direct Myocardial Stimulating Electrodes in Complete Atrioventricular Block.

Bernard S. Levowitz (by invitation), William B. Ford,

and James W. Smith, Jr. (by invitation), Pittsburgh, Pa.

Direct stimulation of the heart through a myocardial electrode has been used in three cases of acquired atrioventricular block associated with Stokes-Adams seizures. Each of these cases failed to respond to an extended trial of medical management in conjunction with extracardiac ventricular stimulation. Our experiences with this technique are described.

The first case was a 77 year old male who had been on an external pacemaker for 2 months. Direct stimulating myocardial electrodes were successfully implanted. His postoperative course was complicated by a delayed splenic rupture attributed to prolonged use of the extracardiac stimulator. In the second case, a 58 year old male, the stimulating electrode broke on the 17th postoperative day. The patient reverted to his idioventricular rate of 30 which subsequently slowed to 10 and then went into cardiac standstill. Following thoractomy, massage and re-implantation of a second pair of electrodes, the patient recovered uneventfully. The third patient was a 69 year old male in poor condition who exhibited progressive deterioration under medical management. His remarkable recovery and rehabilitation after placement of direct stimulating electrodes was most encouraging.

Molar lactate and sympathetic amines were used to combat postoperative hypotension in these cases. The anesthetic management and considerations governing choice of electrode and pacemaker are discussed

2. Surgical Correction of Transposition of the Great Vessels - A Five-Year Survey.

Thomas G. Baffes, Maurice Lev (by invitation), Milton H. Paul

(by invitation), Robert A. Miller (by invitation),

William L. Riker (by invitation), Arthur DeBoer

(by invitation), and Willis J. Potts, Chicago, Ill.

The first case of transposition of the great vessels was operated upon at The Children's Memorial Hospital in March, 1955. Since then, 117 cases have been done by the technique of partial correction, with 34 deaths - a mortality rate of 29.0%. However, the mortality has been markedly reduced during the past two years. In 1955-1957, the mortality was around 50%. During 1958 and 1959, it dropped to 11.4% and 8.3% respectively. The factors responsible for this marked drop in mortality are discussed. Primarily, they revolve around a better understanding of proper management of the high pulmonary artery pressure during the operative procedure.

The 83 survivors from March, 1955 until September, 1959, have been followed from five years to six months. The clinical results were graded as follows: Good 70%; Fair 22%; Poor 2%. Six per cent, or five cases, were lost to follow-up to this date The method of grading is described.

Special attention is paid to the infant group - those children less than six months of age. It is noted that the greatest improvement in mortality and most dramatic clinical improvement has occurred in the infant group, offering a good chance for survival to those most critically ill patients.

The pathology of transposition has been re-evaluated, and a more

accurate classification has been devised by Dr. Maurice Lev. This is

included and is evaluated in terms of the available physiologic data on the autopsied specimens and our operative cases.

In closing, we describe our efforts in the laboratory to develop total correction of the transposition defect and our version of some of the problems still to be solved.

3. Surgical Palliation in Patients with Ebstein's Anomaly and Congenital Hypoplasia of the Right Ventricle.

Milton Weinberg, Jr. (by invitation), Juan P. Bicoff

(by invitation), Lawrence Luan (by invitation),

Zwi Steiger (by invitation), Benjamin M. Gasul

(by invitation), and Egbert H Fell, Chicago, Ill

Ebstein's anomaly of the heart is characterized hemodynamically by an obstruction to right atrial emptying, a result of displacement of the tricuspid valve and a consequent reduction in the volume and functional capacity of the right ventricle. A similar physiologic obstruction is also seen in the rarer congenital hypoplasia of the right ventricle. At the time of presenting this summary, anastomoses between the superior vena cava and the right main pulmonary artery have been performed in two children with Ebstein's anomaly and in one child with congenital hypoplasia of the right ventricle, thereby effecting a partial by-pass of the right side of the heart. Significant clinical improvement has been observed in the two surviving children, and post-operative studies indicate that the procedure is a physiologically sound method of achieving palliation in these anomalies.

End-to-end anastomoses were done on two of the patients and an end-to-side anastomosis, distal right main pulmonary artery to distal superior vena cava, was done on the third patient. Specific complications resulting from temporary superior vena caval occlusion, a necessary step in performing the end-to-end anastomosis, were observed in one of the patients, and the end-to-side technic is preferred, with division of the cava after completion of the anastomosis.

The possible desirability of closure of an accompanying atrial septal defect is suggested by study of the pre- and post-operative hemodynamic data. Although the effectiveness of the procedure in accomplishing a satisfactory degree of right atrial decompression during the years of growth and increasing cardiac output has not been established, the early favorable results would seem to justify its continued use in these patients with progressive disability.

4. Myocardial Infarction in Infancy: The Surgical Management of a Complication of Congenital Origin of the Left Coronary Artery from the Pulmonary Artery.

David C. Sabiston, Jr., Salvatore Pelargonio (by invitation),

and Helen B. Taussig (by invitation), Baltimore, Md

The diagnosis of myocardial infarction in infancy is being made during life with increasing frequency. In most instances this condition is the result of the congenital origin of the left coronary artery from the pulmonary artery. Under these circumstances the right coronary artery arises normally from the aorta and is supplied with oxygenated blood at systemic arterial pressure. The left coronary artery arises from the pulmonary artery which contains blood of diminished oxygen saturation and with lower pressure. After birth the left ventricle becomes progressively more ischemic and infarction occurs. A study of the reports in the literature as well as our own experience shows that the mortality in untreated cases approaches 100% with death usually occurring in the first year.

Coronary injection and perfusion studies on autopsy specimens were performed and the results showed that flow in the left coronary artery is retrograde. Determinations of pressure, flow, and oxygen saturation at operation have confirmed the fact that blood in this vessel drains into the pulmonary artery. These observations led to the conclusion that ligation of the left coronary artery, a procedure previously advocated by others, is a logical and effective method of therapy.

Twelve infants with this condition have been studied at The Johns Hopkins Hospital. Of these, seven had no surgical therapy and died within a year. The five remaining patients were operated upon with ligation of the left coronary artery or de-epicardiahzation or both. Three are alive and essentially asymptomatic. Two others with severe myocardial damage died at the time of thoracotomy. The diagnostic, physiologic, and pathologic features will be presented and the cardiodynamics illustrated by cine-angiocardiography

5. Diagnosis and Surgical Treatment of Intracardiac Myxoma and Rhabdomyoma.

Rodman E Taber and Conrad R. Lam, Detroit, Mich.

Open heart surgery with the pump oxygenator has made resection of intracardiac tumors practical and safe. This report presents our experience with three such tumors, each of which presented a different clinical picture. Two patients had right atrial myxomas which produced obstruction of the tricuspid valve. One patient was cyanotic due to a right-to-left shunt through an atrial septal defect while the other exhibited signs of severe tricuspid stenosis. The tumor had prolapsed through the tricuspid valve in both instances. Resection of the tumors accompanied by closure of the atrial septal defect in the first patient was followed by prompt recovery.

Ginecardiography and cardiac catheterization demonstrated obstruction in the right ventricular outflow tract of the third patient. At the time of open heart surgery, the tumor mass was found to arise in both the ventricular and atrial septa. Resection of the right ventricular portion of the tumor was carried out to relieve the obstruction. The tumor proved to be a rhabdomyoma. Recovery followed with relief of the preoperative symptoms. This patient represents the first reported case of preoperative diagnosis and surgical treatment of cardiac rhabdomyoma.

6. Vasomotor Activity During Total Body Perfusion.

Paul W. Sanger, Frederick H. Taylor, and Francis Robicsek

(by invitation), Charlotte, N. C.

Observations made during open heart operations indicate that there are changes of unknown origin in the circulatory dynamics during total body perfusion. The perfusion pressure fluctuates despite unchanged flow-rate; on the other hand, if effort is made to keep this pressure constant, the flow has to be adjusted repeatedly. There are also unexplained shifts in blood volume from the patient to the extracorporeal circuit and vice versa.

To investigate these phenomena the authors recorded arterial and venous perfusion pressures, systemic circulatory resistance, and flow-rate in 35 human total body perfusions. They conclude their observations as follows:

The circulatory system shows vasomotor activity during cardio-pulmonary by-pass. In most of the cases there is a vasodilatory phase at the beginning of the perfusion which is followed by generalized vasoconstriction. If the total body perfusion is prolonged, these phases are usually followed by a vasoparalytic state.

Description of two flowmeters, one especially designed to measure the blood flow through the arterial (return) line, the other to measure free discharge (gravity venous outflow), is given.