Assessment of the mid systolic click late systolic murmur syndrome by noninvasive methods.

In patients with the mid systolic click/late systolic murmur syndrome (MSC/LSM Sy) a ballooning, billowing or aneurysmal protrusion of one or both mitral leaflets has previously been described in angiographic studies. It is accepted that besides angiography noninvasive methods such as dynamic electrocardiography, phonocardiography, apexcardiography and echocardiography can provide valuable information in the diagnosis of this syndrome. Little is known however about diagnostic value and sensitivity of these methods. The dynamic Ecg, recorded during an average of 10 hours, showed in 8/20 patients (40%) one or several significant arrhythmias such as frequent ventricular premature contractions (VPCs) (greater than 12/min), multifocal VPCs, VPCs in a row or ventricular tachycardia, or 2 degrees SA-block. 12/20 patients (60%) showed in the phonocardiogram a movement of the click toward the first heart sound when the patients' position was changed from supine to sitting. In 40% of the patients a double or triple click was recorded. A late systolic bulge in the apexcardiogram was seen in 13/20 patients (65%). In one patient the recording was not successful. Echocardiographic signs of abnormal posterior movement (prolapse) of one or both mitral leaflets were recorded in 15/20 patients (75%). Five echocardiograms did not show any abnormality, but all these cases demonstrated in their apexcardiogram a late systolic bulge. We believe that in patients with the MSC/LSM Sy a mitral valve abnormality can be documented adequately by noninvasive methods.