[Left ventricular global and segmental function in pure mitral valve prolapse with poor tolerance for exertion].

Poor effort tolerance is observed in a small percentage of cases of idiopathic mitral valve prolapse (IMVP). The aim of this study was to assess the possible left ventricular dysfunction in such cases, responsible for poor effort tolerance. Left ventricular function and segmental wall motion were studied retrospectively in a group of 17 patients with IMVP. The patients, average age 53 +/- 12 years, had poor effort tolerance (ST segment depression of 2 to 4 mm in 15 cases, drop in blood pressure in 6 cases) justifying catheter and angiographic studies. All patients had IMVP confirmed on RAO left ventriculography. There was no associated mitral regurgitation or coronary artery disease. Left ventricular function was studied by parameters of global function (systolic and diastolic parameters, volume measurements) and by a quantitative study of segmental wall contraction. The method used for studying regional wall motion was an application of the Stanford method in which segmental shortening is studied over all the endocavitary contour of the LV during an angiographic cycle filmed at 50 frames/second in the RAO projection. The time and velocity amplitudes of wall motion were measured during systole and diastole. The same methodology was applied to 21 normal control subjects. The results showed abnormal volumic compliance and wall motion in the IMVP group. Asynergy was mainly confined to the antero-lateral wall of the LV. The amplitude of contraction was generally normal but the contraction was slower and finished earlier. In the same zone, relaxation was abnormally early and lasted longer.(ABSTRACT TRUNCATED AT 250 WORDS)