THE DURATION OF LEFT VENTRICULAR SYSTOLE IN MITRAL INCOMPETENCE BY

In mitral incompetence the left ventricle has two exits and it has been suggested that diminished resistance to emptying causes left ventricular systole to be shorter than normal (Brigden and Leatham, 1953). Theoretically the elevation of left ventricular end-diastolic pressure that is found in severe mitral incompetence (Ross et al., 1958; Nixon, 1961a) should result in prolongation of systole. The purpose of this communication is to report measurements of left ventricular systole in patients with mitral incompetence, and to consider their significance. MATERIAL AND METHODS Patients with chronic rheumatic mitral valvular disease submitted to diagnostic left heart catheteri-zation were selected for this study provided they were free from evidence of congestive heart failure, aortic valvular, hypertensive, or ischaemic heart disease: six had atrial fibrillation and were severely disabled by their mitral disease. During cardiac catheterization mean arterial blood pressure lay between 80 and 100 mm. Hg in five cases; in one it was 110 mm. Hg. Pulmonary hyper-tension was present, average pulmonary arterial systolic pressures lying between 40 and 60 mm. Hg. The diagnosis of pure or predominant incompetence was made from the presence of all of the follow-ing findings: clinical and radiological evidence of left ventricular enlargement; left ventricular apica