Syndrome of mitral valve prolapse: current perspectives

P-wave signal-averaged electrocardiogram in patients with idiopathic mitral valve prolapse syndrome and supraventricular arrhythmias

The aim of the study was to assess whether the P-wave triggered signal-averaged ECG (SAECG) used in patients with idiopathic mitral valve prolapse syndrome could predict the risk of the development of supraventricular arrhythmias. Fifty patients with idiopathic mitral valve prolapse syndrome (15 men, 35 women, mean age: 37 +/- 9 years) were prospectively studied. P-wave triggered SAECG was recorded with a commercially available system (HIPEC-200HA Aerotel). The following parameters were calculated: the root-mean-square voltage for the terminal 10, 20, 30 ms of filtered P-wave (RMS10,20,30) and time duration of filtered P-wave (PWD). Nine patients with mitral valve prolapse syndrome (18%) revealed the occurrence of supraventricular arrhythmias on Holter monitoring whereas of the remaining 41 (82%), no clinically relevant supraventricular arrhythmias were detected. We found PWD values to be significantly longer in patients with supraventricular arrhythmias when compared with those without arrhythmias: 119.8 +/- 6.9 ms vs. 111.7 +/- 12.1 ms, respectively, P < 0.02. We conclude that P-wave triggered SAECG could be a useful technique for detecting patients with idiopathic mitral valve prolapse syndrome at risk of paroxysmal supraventricular arrhythmias.

Mitral valve billowing and prolapse--an overview

Three decades after it was demonstrated that nonejection systolic clicks and late systolic murmurs have a mitral valve origin and that a specific syndrome is associated with the primary degenerative mitral lesion, numerous questions remain unanswered. A principal cause of confusion is the use of the term 'prolapse', which essentially implies a pathological state, in many patients with minimal evidence of a mitral valve anomaly. It should be recognised that no specific feature, whether evaluated by high standard echocardiography or indeed by careful morphological and histological examination, can be defined which distinguishes a normal variant from a pathological valve. There is a gradation from the normal billowing during ventricular systole of mitral leaflet bodies to marked billowing. With advanced billowing or floppy leaflets, failure of leaflet edge apposition supervenes (true prolapse). This is functionally abnormal and allows mitral regurgitation. Prolapse in turn may progress to a flail leaflet and hence gross regurgitation. Relatively rare complications of this degenerative mitral valve anomaly include systemic emboli, infective endocarditis, arrhythmias and, arguably, autonomic nervous system abnormalities. An attempt is made to clarify the management of some symptoms and other aspects of mitral prolapse-including rheumatic anterior leaflet prolapse (without billowing) which remains prevalent in South Africa and Third World countries.