PREMATURE MITRAL VALVE CLOSURE: A HEMODYNAMIC EXPLANATION FOR ABSENCE OF THE FIRST SOUND IN AORTIC INSUFFICIENCY

The phenomenon of premature mitral valve closure is described in three patients with severe aortic insufficiency and related to absence of the first heart sound.

The occurrence of premature mitral closure is favored by severe aortic regurgitation probably with increased impedance to left ventricular filling.

Available evidence suggests that this phenomenon usually occurs in the more rapidly developing forms of aortic incompetence (bacterial endocarditis, post surgical, and traumatic rupture of the valve), that it is uncommon, and that it often implies a grave prognosis.

It should be suspected when the apical first heart sound is absent in aortic incompetence.

HEART DISEASE IN OLD AGE

In a post-mortem analysis of 1,500 patients, aged 70 years or more, heart disease and malignancy were the two major causes of death. Coronary disease was exceedingly prevalent, almost one in five being subject to this form of heart disease, and 13% dying from its effects. The levelling of the sex ratio in coronary disease in the aged was a striking feature. The clinical manifestations of coronary thrombosis were often atypical. The incidence of demonstrable coronary thrombosis was as high as in younger age groups. The pathological findings and the incidence of local complications in coronary disease were similar to those in other age groups. Other causes of heart failure were relatively infrequent. Certain features of these conditions in old age are discussed. Cardiac amyloidosis, in the form associated with senility, occurred in a very few cases but did not contribute to heart failure.

PERSISTENT HYPOKALEMIA FOLLOWING OPEN-HEART SURGERY

Six patients who exhibited persistent hypokalemia after open-heart surgery with a dilute blood perfusion mixture are discussed. All these patients had acquired heart disease with heart failure as their predominant problem and had been on long-term diuretic treatment with oral potassium replacement. It was not possible to predict with any degree of certainty which patients would develop hypokalemia postoperatively, but the clinical points discussed indicated that frequent measurement of serum potassium was necessary until the value appeared stable. The authors think that the hypokalemia results from long-term tissue potassium depletion, and that hemodynamic improvement following open-heart surgery may facilitate the return of potassium into the cells and thus reduce the serum level.

DIAGNOSTIC VALUE OF THE FIRST AND SECOND DERIVATIVES OF THE ARTERIAL PRESSURE PULSE IN AORTIC VALVE DISEASE AND IN HYPERTROPHIC SUBAORTIC STENOSIS

The brachial arterial dp/dt was continuously computed by means of an electronic differentiating circuit in 117 patients and 23 normal subjects. The peak dp/dt averaged 1092±372 (S.D.) mm. Hg/sec. in 32 patients with idiopathic hypertrophic subaortic stenosis, 547±94 mm. Hg/sec. in six patients with discrete subvalvular subaortic stenosis, 811±185 mm. Hg/sec. in 23 normal subjects, 358±85 mm. Hg/sec. in 29 patients with valvular aortic stenosis, 724±212 mm. Hg/sec. in 25 patients with combined aortic stenosis and regurgitation, and 1736±530 mm. Hg/sec. in 24 patients with pure aortic regurgitation. It is suggested that the elevated peak dp/dt seen in patients with hypertrophic stenosis is due to the absence of obstruction to ejection early in systole. In contrast, patients with valvular and discrete subvalvular stenosis, who exhibit fixed obstruction to outflow throughout ventricular systole, had a peak dp/dt that tended to be lower than normal. Calculation of the second derivative (d 2 p/dt 2 ) of the arterial pressure pulse provided even better separation of the various groups of patients studied. The analyses of the dp/dt and of the d 2 p/dt 2 of the brachial artery pressure pulse afford a simple and reliable assessment of the nature and location of left ventricular outflow obstruction and are helpful in the differentiation of valvular aortic stenosis, combined stenosis and regurgitation, and pure aortic regurgitation.

P-WAVE ANALYSIS IN VALVULAR HEART DISEASE

Electrocardiographic analysis of the P waves occurring in a series of 113 normal subjects and 100 patients with specifically defined valvular lesions are reviewed. The former methods of analysis showed a marked lack of specificity.

By dividing the P wave in lead V 1 into initial and terminal portions, a measure designated as the P terminal force has been derived. This measure is of value in two respects: (1) it correctly separates normal subjects from those patients with left-sided valvular lesions in 92 per cent of this series and (2) once a given valve lesion is suspected clinically, this measure enables one to make an estimation of the severity of that lesion from the degree of abnormality of the P terminal force at V 1 . The P terminal force does not indicate the type of valvular disease present, nor does it correlate with any one specific hemodynamic measure. The abnormality does appear to be related, within each separate type of valve disease, to the specific hemodynamic abnormality of that type of valvular involvement.

The anatomic and electrophysiologic changes that might relate to these P-wave changes are discussed.

THE CHANGING PATTERN OF THE AORTIC VALVE REPAIR

The changes and improvements in the surgical treatment of aortic valve disease in 296 patients, who were operated on between 1953 and 1965, are illustrated and discussed in general terms. Several of the early techniques, such as transventricular dilation, insertion of a homograft aortic valve in the descending thoracic aorta, fabric replacement of one cusp or the entire valve, and ice-chip arrest of the heart, are now obsolete. Total replacement with a ball-valve prosthesis or an aortic valve homograft while the coronary arteries are perfused with blood is the currently popular technique. The results of a hemodynamic follow-up study two years after surgery are also included.