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Twenty-one consecutive Black African patients with severe pure mitral stenosis were evaluated hemodynamically. It was found that advanced mitral stenosis presents itself in Kenya at a very young age (22.9 ± 9.6 years, mean ± S.D.), with all but three patients under thirty. Left ventricular angiography demonstrated significant impairment of left ventricular function with 50% of patients having abnormally low valves (mean ejection fraction 0.50 ± 0.11). This diminished ejection fraction was related primarily to diffuse hypokinesia and an increased end-systolic volume. There was a significant deterioration of ejection fraction with increasing age which could not be correlated to increased severity of mitral stenosis or pulmonary hypertension. It is proposed that the diffuseness of the myocardial involvement and its progression with age in a young population without coronary artery disease represents the resoltuion of the acute inflammatory process of rheumatic fever in diffuse fibrosis of the myocardium and/or an occlusive vasculitis.

Summary The medical problems encountered during the care of patients undergoing mitral and multiple valve replacement have been discussed. Included are remarks regarding particular problems which have been encountered at the University of Oregon Medical School, and the philosophy which has evolved here regarding the care of these patients. The discussion includes some aspects of the preoperative evaluation, preoperative medical care, and the role of internist during surgery. Postopertive medical management is considered at length, with special reference to complications.

Digitalis augments the contractility of the normal and the failing heart. In nonfailing cardiac disease the positive inotropic action is not translated into increased cardiac output, largely due to increased vascular resistance and decreased cardiac filling. Digitalization does not affect ventilation or cardiac output during physical exercise, and has been shown to reduce the postexercise oxygen debt in patients with enlarged hearts not in failure. In experimental animals, digitalis prevents depression of cardiac function by anesthesia and by anoxia and hemorrhagic shock. There is also evidence that treatment of the overloaded but nonfailing heart may delay or reduce the increment in cardiac hypertrophy. The experimental evidence indicates that digitalis would rarely be harmful in patients with cardiomegaly without overt congestive heart failure, and may have definite prophylactic value when stress is anticipated.

An analysis of the postoperative course in twenty-eight patients who had complete correction of tetralogy of Fallot is presented. Pertinent preoperative findings are summarized and the operative procedure is briefly described. During or following surgery, seven patients had a syndrome of low cardiac output, which was lethal in four. Factors which may have contributed to the development of this state are discussed. The operative mortality rate was 14 per cent. One patient died during re-operation for persistence of the ventricular septal defect; the over-all mortality rate was 18 per cent. Congestive heart failure developed in 42 per cent of surviving patients. This was transient in some and had a more protracted course in others. All patients recovered and late improvement was impressive. Possible mechanisms for this incidence of heart failure are presented. The ultimate result from surgery was considered excellent in the majority of cases. It is concluded that total correction is feasible in most patients with tetralogy of Fallot, with an acceptable surgical mortality.

Responses to infusions of isoproterenol and methoxamine and to acute administration of ouabain have been studied in 17 patients with aortic insufficiency. Cardiac output was consistently increased and left heart filling pressures were reduced with isoproterenol. Forward stroke volume and the effective emptying ratio of the left ventricle both increased. These effects were related to increased inotropy, decreased impedance to left ventricular outflow and a diminished regurgitant volume. Methoxamine caused a marked rise in left heart pressures but the cardiac output remained unchanged or fell, the result of augmented systemic resistance with no associated direct inotropic effect. Ouabain caused no gross hemodynamic alterations, as has been noted previously in patients not in heart failure. These findings suggest that isoproterenol might be of considerable use in the clinical management of patients with aortic regurgitation. Methoxamine would be disadvantageous as a vasopressor drug in such patients, and perhaps in all situations requiring vasopressor therapy. The role of cardiac glycosides in treating patients with cardiac dilatation but without overt heart failure is questionable.

The results of aortic valve replacement with the Starr-Edwards prosthesis are reviewed in 86 patients. The total early and late mortality rate was 24 per cent. This fell to 13 per cent in 1964, and can be expected to decline further. Nearly all survivors are greatly improved by surgery. Detailed follow-up of 6 months to 3 years is available in 50 patients. All but one had symptoms prior to operation, and hemodynamic study preoperatively demonstrated gross abnormalities in most. Sixty-six per cent became asymptomatic, whereas mild limitation to exercise persisted in another 40 per cent. Angina pectoris disappeared in 32 of 34 instances. Sixty-eight per cent had a normal or only slightly enlarged heart after operation. Electrocardiographic evidence of left ventricular hypertrophy disappeared in 58 per cent. Postoperative hemodynamic studies usually demonstrated some mild residual hemodynamic abnormality, probably attributable to irreversible myocardial damage resulting from long-standing left ventricular hypertrophy and/or dilatation. Postoperative complications included regurgitation around the prosthesis, which was rarely of hemodynamic consequence, bacterial endocarditis (rare), traumatic hemolytic anemia (rare), and systemic arterial embolization. Thromboembolism remains the major unsolved problem of aortic valve replacement, and anticoagulant drugs have not been proved to be of value in preventing this. Indications for aortic valve replacement are discussed in terms of the current mortality rate and incidence of complications, the proved clinical and hemodynamic benefits, and the natural history of the various types of aortic lesions. All symptomatic patients with aortic stenosis, and all Class III or IV patients with aortic regurgitation are candidates for surgery. In addition, surgery is recommended in relatively asymptomatic patients with aortic stenosis who have a transvalvular peak systolic gradient of more than 70 mm. Hg, and in those with aortic regurgitation if there is gross cardiac enlargement, angina pectoris, or abnormal left heart dynamics. The possibility of underestimating the hemodynamic severity of a mixed aortic valve lesion was discussed.

The dependability of RVA in the evaluation of TI was studied in 141 patients with congenital or rheumatic disease. In patients over age 10, angiocardiography revealed TI in 13 and was negative in 27. Eight with positive RVA had cardiac operation and TI was confirmed in seven; three not having been operated upon were probably false positives. Six with negative RVA had an operation and no TI was detected. In 20 per cent of 95 younger patients, RVA revealed TI, often believed catheter induced. RA pressure criteria commonly employed in the hemodynamic diagnosis of TI were tested. RA pressure level and contour were analyzed in 27 cases proved negative for TI by RVA and in seven proved positive by operation. An X descent shallower than Y correlated better with atrial fibrillation than with TI; X deeper than Y correlated better with sinus rhythm than with tricuspid competence. RVA can exclude TI but yields false positive studies. RA pressure contour is believed not to have the usually accepted significance.

A fifteen year old boy, whose case is reported here, survived a myocardial infarction which was apparently related to strenuous exertion. The anatomic diagnosis, based on electrocardiographic and vectorcardiographic observations, was confirmed by coronary arteriograms which demonstrated marked narrowing of both major branches of the left coronary artery. The etiologic diagnosis of coronary atherosclerosis is suggested, primarily because of exclusion of other possibilities.

The complications in 191 consecutive transseptal catheterizations are described. These included puncture of the wall of the heart in 9 cases, with 1 death, hemopericardium observed at the time of operation, a fatal coronary occlusion from an embolus which originated in a Lehman catheter, electrocardiographic changes of coronary insufficiency, and thrombophlebitis of the right lower extremity with pulmonary embolism.

Summary This paper describes the role of digitalis in cardiac surgical patients as viewed in our hospital. Routine preoperative digitalis is given to almost all patients who are to have intracardiac surgery, whether or not cardiopulmonary bypass is to be used. The positive inotropic effect of digitalis and its action on atrioventricular conduction are discussed in relation to cardiac surgery. The use of digitalis and the means of its administration before, during and after surgery are described. Postoperative digitalis intoxication and its treatment are outlined.

A case of reversed reciprocating paroxysmal tachycardia in a patient with the WPW syndrome is reported. The tachycardia was controlled by guanethidine. The blocking of sympathetic activity, with resultant predominent vagal influence on the conduction pathways of the A-V node and the anomalous bundle, is offered as an explanation for the control of this arrhythmia.

Left ventricular end-systolic and end-diastolic volumes were measured by a thermodilution technic in four patients with idiopathic left ventricular hypertrophy. Two patients had no outflow tract obstruction at rest and the ventricular end-diastolic volumes were 90 and 107 ml. per M 2 . Two patients with idiopathic hypertrophic subaortic stenosis (IHSAS) with large gradients, had end-diastolic volumes of 69 and 67 ml. per M 2 . The lower limit of normal for this value in our laboratory is 90 ml. per M 2 . The low end-diastolic volumes in the two patients with IHSAS were associated with ventricular end-diastolic pressures of 18 and 20 mm. Hg, indicating that the diastolic compliance of the left ventricle was severely reduced. This low compliance produced a high mean left atrial pressure and a low stroke volume, due to inadequate ventricular filling. It is postulated that in some cases of IHSAS, such handicaps may be as important as outflow tract obstruction. When methoxamine was administered to two patients with IHSAS, the systemic pressure rose and the outflow gradient was lessened in both. However, in one case the ventricular enddiastolic volume rose from 69 to 79 ml. per M 2 ., and in the other it fell from 90 to 59 ml. per M 2 . Based on our data, and other studies from the literature, it is suggested that systemic diastolic pressure is an important determinant of the outflow gradient in IHSAS. A rise in systemic diastolic pressure may reduce, or even nullify, the effects of either a reduced ventricular systolic volume or positive inotropic stimulation, both of which have been shown to increase outflow obstruction. It is proposed that the gradient in IHSAS depends on a complex interplay of variables, some tending to increase the gradient, and some tending to decrease it. It may thus be difficult to predict the effect of any agent or maneuver in a given patient with IHSAS.

Nineteen geriatric patients with sustained, mild to moderate hypertension in addition to cerebrovascular disease were studied for 4 months by means of a double-blind crossover technique in which mebutamate was compared to an inert placebo. No significant antihypertensive effect was observed in the 19 geriatric patients treated with mebutamate (Capla). Over 40 per cent of the patients complained of drowsiness while receiving the drug. There was no evidence of renal or hepatic impairment during the period of observation.

A patient who has rheumatic heart disease with predominant mitral valve involvement and who had systemic hypertension as a result of renal artery stenosis is presented. The hemodynamic changes resulting from surgical correction of the hypertension are discussed. The difficulty in interpreting pulmonary wedge or left atrial pressures in assessing the degree of mitral valve disease in the presence of systemic hypertension is emphasized.