Citations

A total of 131 patients with the partial form of common atrioventricular canal were operated on between March, 1955 and January, 1964. The over-all hospital mortality rate was 3.8%; no deaths occurred in patients who had no or only mild incompetence of the mitral valve. Permanent heart block has not occurred in the last 93 cases. Results have been good in general, although there is evidence of residual mitral valve incompetence in many patients. In the few who had severe incompetence at the mitral valve before repair, the results have been considerably less satisfactory than in the group as a whole; therefore, further work is needed on this aspect of the problem.

Of the 614 open-heart operations performed at the Mayo Clinic for acquired aortic valvular disease, 130 were performed on patients who also required repair of other valves. Review of the remaining 484 operations resulted in the following observations. Operation for acquired aortic valvular disease may now be accomplished with a hospital mortality rate of 4%. The incidence of late death and failure of patients to improve has averaged 44% for previously employed techniques of valvular repair. Failure of the valve or prosthesis to function properly was the most common cause of late failure after operations in which these earlier methods were used. In the 138 more recent cases, in which operations employing the aortic ball valve (Starr-Edwards prosthesis) were used, the incidence of late failure has been reduced to 14%, and failure of the prosthesis to function properly has not yet occurred in the absence of infection. Late bacterial endocarditis and thromboembolism were the most serious problems associated with use of the ball-valve prosthesis. In contrast with the late results of the former techniques, use of the ball valve has resulted in improvement for 79% of the patients; in the great majority of these there has been a dramatic return to normal living. Despite the highly satisfactory results of current methods, the fact that 14% of patients have already died after an initially successful operative result, and that another 12% have suffered complications causing their late result to be less than totally satisfactory, indicates that the policy of recommending for operation only those patients who have significant and progressive cardiac disability should be continued.

The effect of valvular insufficiency on left ventricular volumes was studied by an angiographic method in 37 patients. Ejection of the additional volume load imposed by valvular insufficiency was achieved by an increase in end-diastolic volume and not by increasing the proportion of end-diastolic volume ejected. Of the 37 patients, 16 (43 per cent) had a significant reduction in the fraction of end-diastolic volume ejected per beat. These patients performed significantly less stroke work from a given end-diastolic fiber length (end-diastolic volume) than did the others and evidence is presented that they had impaired myocardial function. An index of myocardial contractility is derived which relates stroke work to end-diastolic volume. The magnitude of left ventricular volumes is determined in part by the severity of the volume load but a further increase in volume without necessarily a further increase in ejection occurs in those patients with impaired myocardial function. Valvular insufficiency is quantitated from the difference between left ventricular ejection volume determined angiographically and forward stroke volume determined from indicator-dilution curves. The results show good agreement with subsequent surgical findings in the 15 patients who underwent operation.

The cardiovascular response to angiographic contrast medium was studied in 28 patients undergoing diagnostic angiocardiography under anesthesia. A transient phase of hypotension and tachycardia similar to that described by other authors was noted. Cardiac output was increased initially by 50 per cent and returned to the base line in 20 minutes. Peripheral blood flow increased by 100 per cent, apparently due to the direct effect of the hyperosmotic solution on the vascular smooth muscle. Hemodilution, maximal 2 to 4 minutes after injection of contrast medium, suggested a transient increase in circulating blood volume. Increased ventricular filling pressures, which were thought to be due to hypervolemia, were associated with increased left ventricular stroke work.

The analysis and description of the preoperative and postoperative vectorcardiograms in tetralogy of Fallot are presented. The spatial orientation of the maximum QRS vectors to the right, anteriorly, and inferiorly in group I is indicative of right ventricular hypertrophy. In group II patients, the vectorcardiogram showed evidence of increased electrical activity of the left ventricle. Vectorcardiographic patterns of complete right bundle-branch block were noted in nine patients in group III.

Left heart volumes were determined angiographically in 50 subjects of whom 18 had no abnormality of the left heart, 12 had lesions causing pressure overload of the left ventricle, and 20 had lesions causing volume overload of the left ventricle. The left heart volumes were in the normal range in the presence of pressure overload, but, with volume overload, end-diastolic, end-systolic, and atrial volumes were in excess of normal. A linear relationship was demonstrated between end-diastolic and end-systolic volumes, regardless of the pressure load on the ventricle. Thus, for all but one of the cases studied, total left ventricular ejection volume formed a nearly constant proportion of end-diastolic volume.

A case is reported of a man who had an acute painless dissecting hematoma of the aorta, which was diagnosed clinically in the absence of hypertension or known precipitating cause. The successful surgical treatment is described and illustrated. The following diagnostic features were stressed in the absence of pain: sudden onset of symptoms, syncope, acute peripheral arterial occlusion, appearance of aortic insufficiency, and finding of bruits over the course of the aorta. The significance of the symptom of pain in the torso and the possible modes of its production in this condition are considered, and it is suggested that pain in dissecting aneurysm may imply a poor prognosis.

Eighteen cases of stenosis of the branches of the pulmonary artery, seen at the Mayo Clinic, have been reviewed and subdivided into two main types: Type I, stenosis of the main branches of the pulmonary artery, 11 cases, and type II, stenosis of multiple peripheral branches of the pulmonary arteries, seven cases. Of special interest were two cases in which thrombosis occurred as a complication and one case in which surgical relief of multiple areas of stenosis in the peripheral branches of the pulmonary arteries was accomplished. Unexplained pulmonary hypertension necessitates further investigation, which includes cardiac catheterization for measurement of intracardiac pressure and frequently selective angiocardiography. Main branch or peripheral pulmonary artery stenosis should be suspected when a continuous murmur is heard or when poststenotic dilatations of the pulmonary artery branches or areas of decreased pulmonary vasculature can be perceived in the roentgenogram. Angiocardiography is the only technic that permits detailed anatomic evaluation of the entire pulmonary vasculature, especially in the cases associated with severe infundibular or valvular pulmonic stenosis. Stenosis of the branches of the pulmonary artery must be taken into account, when surgical repair of associated cardiovascular defects is considered. These lesions also might complicate anastomotic procedures involving the pulmonary artery in cyanotic patients.

Hemodynamic studies were made 2 weeks after repair of tetralogy of Fallot in 18 cases and 2 months to 6 years after operation in 5 cases. Intracardiac and intravascular pressures, oxygen uptake, arteriovenous oxygen content difference, cardiac output, heart rate, stroke index, and pulmonary and systemic resistance were measured. Residual intracardiac shunts and residual pulmonary stenosis and incompetence were assessed. Results were compared with similar studies on postoperative days 1, 2, and 3. Further insight into patterns of convalescence as well as into the favorable hemodynamic state usually pertaining after repair are provided by these data.