Citations

The morphology of the atrioventricular (A-V) conduction system was studied by serial histologic section in two cases of tricuspid atresia type IB (without transposition of the great arteries, with subpulmonary stenosis). The A-V node was adjacent to the central fibrous body, and its location was indicated by a "dimple" in the floor of the right atrium. The left bundle branches originated unusually close to the nodal-bundle junction. The right bundle branch was markedly elongated in its course to the right septal endocardium. It was situated along the inferior aspect of the channel-like ventricular septal defect as it traversed the septum. The early origin of the left bundle branches and the markedly elongated course of the right bundle branch were such that, theoretically, abnormal spread of the activation wave might result.

Obstructive pulmonary vascular disease (PVD) was evaluated in lung sections taken at autopsy in 53 patients with complete transposition of the great arteries. Twentythree had intact ventricular septa and 30 had ventricular septal defects. Children of similar age and associated defects had widely differing degrees of PVD and presented a spectrum of disease. In a small number of patients, the presence of pulmonic stenosis (congenital or acquired by pulmonary artery banding in infancy), a small ventricular septal defect, or a large atrial septal defect was not protective against the development of severe PVD. The findings of this study demonstrate the need for thorough hemodynamic evaluation of patients with complete transposition of the great arteries prior to repair by present technics. In addition, operation should probably be performed as soon as technically feasible.

Total daily bile acid excretion was measured in 10 patients with primary hypercholesteremia and in nine patients with combined hypercholesteremia and hypertriglyceridemia by using 14 C-labeled cholic acid and 3 H-labeled chenodeoxycholic acid. The average bile acid excretion by the patients with primary hypercholesteremia was 282 mg/day; that by the patients with combined hypercholesteremia and hypertriglyceridemia, 1,094 mg/day. These findings suggest a fundamental difference in cholesterol metabolism in these two types of hyperlipidemia.

During pregnancy, when surgically reparable heart disease can no longer be medically manged, open- or closed-heart surgery is the procedure of choice without prior therapeutic abortion. Cyanotic congenital heart disease in a pregnant patient when completely correctable surgically may be an indication for surgery in itself. Available data suggest that pregnancy per se does not increase the maternal risk of heart surgery with use of extracorporeal circulation. Fetal mortality in our series was 33%.

Postoperative embolism occurred in 35 of 546 patients traced for 2 to 15 years after surgical repair of uncomplicated ASD. A total of 58 embolic episodes occurred, resulting in the death of 11 of these 35 patients. The incidence of embolism was not significantly related to the technique used for surgical repair. Six of the nine patients who had had a preoperative embolism also had an embolism in the postoperative period. The most significant factors associated with an increased risk of postoperative embolism were increased age of the patient, atrial fibrillation, and pulmonary hypertension, all of which are interrelated: seventy-seven per cent (27/35) of patients having a postoperative embolism had either atrial fibrillation or pulmonary hypertension, and 77% (27/35) of patients with postoperative embolism were more than 40 years old at the time of the first embolism. Because actuarial analysis suggests that 30% of patients more than 40 years of age who have atrial fibrillation after repair of ASD may have an embolism within 10 years postoperatively, continuation of anticoagulation therapy indefinitely in these patients is suggested. The highest risk of embolism occurs in the early postoperative period, suggesting the advisability of anticoagulation therapy for all adult patients during convalescence.

Mitral valve function was assessed by roentgen videodensitometry. Mitral reflux was rare when single ventricular ectopic systoles were produced by electronic stimulation of the right or left ventricle at various times in the cardiac cycle. It was also rare during the compensatory pause after the ectopic systole or with the following postectopic systole. Recurrent ventricular ectopic systoles interposed once per cycle were associated with minor reflux when introduced in mid-cycle. Such extrasystoles occurred late enough in the cardiac cycle for the ventricle to relax after the primary systole and for the mitral valve to open before the extrasystole. The extrasystolic contractions were, however, weak and incapable of opening the aortic valve. When interposed early in the cardiac cycle, extrasystolic potentiation of the primary ventricular contraction occurred, and no or minimal mitral reflux was observed.

Complete surgical correction of transposition of the great arteries associated with subvalvular pulmonary stenosis carries a high mortality rate. A new surgical technique that achieves redirection of the ventricular outflows and relieves pulmonary stenosis by bypassing it, was successfully used to repair complete transposition of the great arteries associated with ventricular septal defect (VSD) and valvular and subvalvular pulmonary stenosis in a 14½-year-old patient. The repair consists of (1) division of the pulmonary artery, the cardiac end of which is oversewn, (2) repair of the VSD with a patch in such a way as to connect the left ventricle with the aorta, and (3) reconstruction of the pulmonary artery with an aortic homograft, including the aortic valve, which is anastomosed between the distal end of the pulmonary artery and the right ventricle. A review of the cases in which the current techniques were used indicates that the location and nature of the obstruction in the left ventricular outflow tract defies successful repair in most instances. Localized ridges and diffuse hypoplastic outflow tracts are recognized causes of obstruction, but anomalies of the mitral valve commonly contribute to or are the primary cause of subvalvular obstruction.

Fourteen hearts with tricuspid atresia were reviewed at autopsy. The study included examples of normally related great arteries and of transposition of the great arteries; instances of pulmonary stenosis were present in both groups. In these examples of tricuspid atresia the size of the right ventricle depended on the size of the ventricular septal defect. The ventricular septal defect and the right ventricle usually were smaller in proportion to the size of the heart in specimens with normally related great arteries. In the absence of transposition of the great arteries, the ventricular septal defect was found to be the site of obstruction to pulmonary flow, and its size in relation to the size of the aorta determined the size of the pulmonary artery. Morphologic abnormalities exist in the region in which the proximal portions of the major atrioventricular conduction system (A-V node, bundle of His, origin of bundle branches) normally are located; thus, anatomic abnormalities in the course of the atrioventricular conduction tissue could be expected in tricuspid atresia. Based on histologic evidence, severe elevation of pulmonary vascular resistance, in general, does not occur in infancy in tricuspid atresia.

A total of 696 patients with atrial septal defect (ASD) of either the secundum (90.5%) or the sinus venosus (9.5%) type were operated on at the Mayo Clinic from 1954 through 1965. Pulmonary hypertension (PHT, defined as pulmonary artery systolic pressure of 60 mm Hg or greater) or chronic congestive cardiac failure (CCF) (or both) was associated with 80% of the hospital deaths. For the years 1958 through 1965 (531 cases), the hospital mortality for these three groups was 10% (three of 30), 14% (one of seven), and 18% (two of 11), respectively; only two (0.4%) of the remaining 483 patients died, and both were more than 45 years old (among a total of 93 patients more than 45 years old). There have been no operative deaths among those less than 45 years of age and without PHT or CCF (390 cases) in the years 1958 through 1965. No operative deaths occurred in the years 1963 through 1965. Of 16 patients 60 years or older (1954 through 1965), one has died. A 6- to 12-year follow-up was possible on 397 patients operated on from 1954 through 1960. In the absence of PHT or CCF, 330 survived operation. Among the 53 patients more than 45 years old, four died later (not definitely related to closure of ASD), three were not well, 32 were in excellent health, and 14 were lost to follow-up in 1966. Among the 277 patients less than 45 years old, 10 died later (all but one probably unrelated to closure of ASD), three were unwell, 186 were in excellent health, and 78 were lost to follow-up in 1966. Forty-two patients with PHT survived operation in the period from 1954 through 1960. Ten had pulmonary resistance of more than 640 dynes sec cm -5 ; four of these were well, two had died (with PHT), two had severe PHT, one was in CCF, and one was moderately disabled. Thirty-two had pulmonary resistances of 640 dynes sec cm -5 or less; three of these had died (unrelated to closure of ASD), five were moderately disabled, 16 were in excellent health, and eight were lost to follow-up in 1966. Eighteen patients with CCF survived operation in the period from 1954 through 1960. All had had grade IV disability (New York Heart Association classification). There were three late deaths (one due to severe pulmonary vascular disease and two unrelated to closure of ASD), one patient had grade IV disability, five had grades I to II disability, eight were in excellent health, and one was lost to follow-up in 1966. Paroxysmal arrhythmia occurred in 75 of 397 patients (19%) operated on from 1954 through 1960. In 53 patients it was present preoperatively and persisted postoperatively in 15 of them (28%); in an additional 22 it appeared for the first time after closure of the ASD.

The status of 58 patients, 3 to 57 years of age, with ventricular septal defect and a marked increase in pulmonary vascular resistance (pulmonary obstructive disease) was determined 5 years or longer after diagnostic catheterization. Forty-six (80%) were alive 5 years after that study. The probability of living 5 years was 95% for patients aged 10 through 19 years and 56% for those 20 years of age or older. The dissimilarity of actuarial curves between these two groups is consistent with the hypothesis that pulmonary vascular obstructive disease develops under age 20. Calculated pulmonary resistance increased with age of patient on admission to the study, suggesting its progressive nature. Hemoptysis was rare under age 20, and its presence over this age indicated a poor prognosis. The most common causes of death were "sudden" or "unknown." Most surviving patients were gainfully employed or attending school without severe symptoms.