Citations

Six years have passed since the first successful surgical correction of truncus arteriosus. A review of our experience enables some conclusions regarding the operation. Patients with mild or moderate truncal valve incompetence do not need truncal valve replacement. Patients with severe truncal valve incompetence require valve replacement, which is associated with a significantly increased surgical mortality. The surgical mortality is not increased in hemodynamically favorable patients who have only one pulmonary artery. However, these patients are especially likely to have early development of severe pulmonary vascular disease. The surgical mortality for the patient with uncomplicated disease and two pulmonary arteries, with pulmonary resistance of less than 8.0 units m 2 , is 10%. In patients with pulmonary resistance between 8.0 and 12 units m 2 , the mortality is approximately three times greater. Patients with pulmonary resistances greater than 12.0 units m 2 are probably inoperable. Different hemodynamic criteria must be applied in assessing the operability of patients with a single pulmonary artery. A systemic arterial oxygen saturation less than 85% in a patient with two pulmonary arteries and without pulmonary artery stenosis or a pulmonary artery band usually indicates inoperability. Elective operation usually is deferred until a patient is four years old, but if the patient's clinical condition warrants, the procedure can be done at any time after the age of one year, with a good chance of success. Follow-up on most operated patients has been encouraging.

From 1957 through 1971, 18 patients whose ages ranged from 10 months to 18 years underwent surgical correction of tetralogy of Fallot with absent pulmonary valve. All patients had associated pulmonary arterial aneurysms; in two the left pulmonary artery also was absent. Right middle lobectomy had been performed previously on one patient for lobar emphysema; seven other patients had recurrent pulmonary infections. The ventricular septal defect was closed with a patch in 12 patients and by direct suture in 6. Concomitant infundibular resection was done in all. In four the narrow pulmonary valve annulus was enlarged with an outflow patch, and multiple radial incisions were made in the valve annulus in seven others. The pulmonary arterial aneurysms were not resected in any patients. There were three hopsital deaths (17%) and two late deaths. Complete heart block developed intraoperatively in three patients, all operated on prior to 1963, contributing to the early death of one patient and to the late deaths of the other two. In a follow-up of all 13 survivors at 8 months to 15 years (median 6 years), results were excellent and equal to those of patients who have undergone repair of tetralogy of Fallot with pulmonary valve.

Fifty patients underwent correction of one or two valvular lesions with concomitant insertion of one to three aortocoronary vein bypass grafts. Hospital mortality was 14% and late mortality was 10%. Factors influencing operative mortality were: (1) mitral valve replacement after myocardial infarction; (2) complete obstruction of a coronary artery preoperatively; (3) high left ventricular end-diastolic pressure at rest preoperatively in patients with mitral valve disease; and (4) use of a single aortocoronary graft in the presence of multiple-vessel disease. For patients with significant associated valvular and coronary artery disease, combined correction yields results that appear sufficiently encouraging, judged by mortality and follow-up, to warrant its continued use in selected cases.

A simple classification of atrioventricular block, criteria for diagnosis, and suggested therapy are discussed. The differences between Mobitz I and II second-degree A-V block are reviewed. Good management of patients who have bundle-branch or other forms of intraventricular block depends on informed judgment which includes consideration of (1) the effect of intraventricular conduction disturbances on the pumping action of the heart, and (2) the likelihood that a specific intraventricular conduction disturbance will be complicated by complete heart block. Evidence suggests that common forms of intraventricular disturbance, unlike ventricular fibrillation, do not alter significantly the pumping action of the heart. The role of intraventricular conduction disturbances in the genesis of ventricular fibrillation is assessed. We concluded that only when right bundle-branch block is combined with block of the anterior or posterior fascicle of the left bundle branch is complete heart block sufficiently imminent to warrant special concern. If bilateral block is associated with symptoms of episodic severe bradycardia, pacemaker therapy is indicated.

The echocardiographic features of Ebstein's anomaly include a large anterior chamber, paradoxic ventricular septal motion (type B), increased velocity and amplitude of anterior tricuspid leaflet (ATL) motion, and delayed closure of the ATL. This delayed closure has been thought to be secondary to right bundle-branch block (RBBB). We have studied two patients by simultaneous echocardiography and phonocardiography. The findings in both patients were similar. One patient had RBBB and therefore resembles the previously reported patients. However, the other patient had W-P-W preexcitation syndrome, type B, and is reported here in more detail. The ATL closure of this patient was markedly delayed in spite of right ventricular preexcitation. This finding gives further insight into the altered pathophysiology in Ebstein's anomaly and implies that the delayed ATL closure is probably not due to RBBB and may be a specific feature of this anomaly.

The effect of oral aspirin in doses known to influence in vitro platelet aggregation was evaluated in patients undergoing brachial artery catheterization. Neither arterial thrombus formation nor pulse reduction was affected in patients given aspirin when compared to controls. Aspirin in small doses does not decrease the incidence of vascular occlusion after brachial artery catheterization.

Among certain patients with cardiovascular malformations, a common phenomenon is a ventricular septal defect and absence of anatomic origin of the pulmonary arterial supply from the heart. In this situation, true pulmonary arteries may be present or absent. In the latter case, the pulmonary arterial supply comes through bronchial arteries. When true pulmonary arteries are present, the left and right pulmonary arteries either may be in continuity at their origins (confluence) or they may arise from separate sites (nonconfluence). When confluence is present, the two pulmonary arteries may arise either from an atretic pulmonary trunk or from certain forms of persistent truncus arteriosus. Pulmonary atresia may be localized to the proximal end of the pulmonary trunk or diffuse in this vessel. When nonconfluence is present, each pulmonary artery arises separately from one of three possible sources as follows: (1) a form of persistent truncus arteriosus, (2) through ducti arteriosi from the aortic arch system, or (3) through bronchial arteries from the descending aorta.

During cardiac catheterization in nine patients with ventricular septal defect and seven patients with truncus arteriosus, all with severe pulmonary vascular obstructive disease, hemodynamics were compared while they were breathing first room air and then 100% oxygen. Patients with higher pulmonary vascular resistance had higher systemic vascular resistances. With 100% oxygen, pulmonary vascular resistance decreased and systemic vascular resistance increased in both groups. The effect of oxygen was found to be more pronounced on the systemic than on the pulmonary vascular bed in the patients studied. Indicator-dilution dye curves changed and exhibited characteristics of left-to-right shunts in patients with severe pulmonary vascular obstructive disease, as a result solely of an increase in systemic resistance; that is, without a decrease in pulmonary resistance. It is suggested that in patients with severe pulmonary vascular obstructive disease maintenance of an increased systemic resistance is essential to well being and is a factor in longevity. It is also suggested that any transient decrease in systemic resistance in these patients might initiate a vicious cycle leading to sudden death.

Some, but not all, cardiac arrhythmias are related to pathologic lesions of the cardiac conduction system. Common atrial dysrhythmias and first-degree atrioventricular (A-V) block rarely are explained on the basis of anatomic lesions in specific sites of the conduction system or its blood supply. Second-degree A-V block of Mobitz type II, which may be a precursor of complete (third-degree) heart block, commonly is associated with fibrotic lesions of uncertain etiology in the branching part of the bundle of His or the bundle branches. Ischemic lesions are found less often, and other pathologic processes rarely are present. Chronic complete heart block most often results from nonspecific, fibrotic interruption of the distal bundle of His, or of the first parts of the bundle branches after their origins. Ischemic lesions are uncommonly the cause of chronic block. High-grade A-V block complicating acute myocardial infarction may be associated with infarction of the A-V conduction system, but often morphologic evidence of ischemia cannot be identified. Congenital variants in anatomy of the conduction system are responsible for some relatively uncommon arrhythmias.