Mitral valve prolapse, arrhythmias and sudden death

Some of the classical concepts of mitral valve prolapse (MVP) should be reviewed in the light of recent publications. It is a condition, according to strict echocardiographic criteria excluding near physiological abnormalities, which affects 2 to 3% of the adult population in the industrialised world. Only repetitive atrial arrhythmias and complex ventricular arrhythmias are more common in this condition than in control groups, the differences being more pronounced in cases of mitral regurgitation. The risk of syncope or sudden death is 0.1% per year, hardly any different to that of the rest of the general adult population (0.2%). However, this risk may attain 0.9 to 2% in cases with mitral regurgitation. The causes of sudden death are unclear (haemodynamic, neurohumoral, arrhythmic, etc...), although there is evidence in favour of malignant ventricular arrhythmias. Detailed clinical, electrophysiological, isotopic and anatomopathological studies have raised doubts as to the direct responsibility of the vascular malformation (or its eventual consequences on the atrial and ventricular chambers) in this mode of fatal outcome. On the other hand, localised or diffuse myocardial disease is often observed, usually a- or pauci-symptomatic, associated with MVP, the responsibility of which is more plausible. Therefore, the physician should adopt a flexible attitude towards these patients, reassuring those with benign symptoms at low risk and following up or actively treating the rarer malignant forms (especially familial, syncopal with mitral regurgitation and/or severe arrhythmias).     

Mitral valve prolapse and Marfan syndrome

Marfan syndrome is a multisystemic genetic condition affecting connective tissue. It carries a reduced life expectancy, largely dependent on cardiovascular complications. More common cardiac manifestations such as aortic dissection and aortic valve incompetence have been widely documented in the literature. Mitral valve prolapse (MVP), however, has remained poorly documented. This article aims at exploring the existing literature on the pathophysiology and diagnosis of MVP in patients with Marfan syndrome, defining its current management and outlining the future developments surrounding it.     

Mitral valve prolapse syndrome in athletes]

The syndrome of mitral valve prolapse was diagnosed by means of echocardiography in 11 of 28 top-class athletes with functional systolic murmurs and in 4 of 16 athletes examined irrespective of the physical findings and complaints. The echocardiographic manifestations of the prolapse consisted in delayed systolic flexion of the posterior cusp (3 cases), early systolic prolapse of the posterior cusp (4) and holosystolic prolapse of both cusps (8). It is concluded that the syndrome of mitral valve prolapse occurs in athletes far more often than generally supposed and may be the cause of systolic murmurs, and the development of myocardial dystrophy due to chronic physical overstrain and disorders of cardiac rhythm.     

Mitral valve prolapse syndrome: neuro-endocrinological aspects

Based on analysis of 399 symptomatic patients with mitral valve prolapse (MVP) and the reported experience of others, we developed a clinical classification in order to improve nosology, provide better identification and promote insight into the mechanism of symptoms in patients with MVP. The heading of anatomic MVP designates those in whom symptoms or complications were primarily or directly related to valvular dysfunction and the heading of MVP syndrome designates those patients in whom symptoms cannot be explained on the basis of valvular dysfunction alone. Patients with MVP syndrome present with a symptom complex which results from various forms of neuroendocrine or autonomic dysfunction; the most common symptoms include chest pain, palpitations, cardiac arrhythmias, orthostatic phenomena, syncope, presyncope, fatigue, exercise intolerance, dyspnea and neuropsychiatric symptoms (Table 1). Mechanisms underlying the condition have been shown to include increased adrenergic activity, disturbances of catecholamine regulation, hyperresponsiveness to adrenergic stimulation, anomalous beta-adrenergic receptors, dysfunction of the parasympathetic portion of the autonomic nervous system, disturbances in renin-aldosterone regulation, decreased intravascular volume, diminished left ventricular diastolic volume in the upright position as well as abnormal secretion of atrial natriuretic factor (Table 2). In MVP syndrome, alterations of the heart, kidney, the adrenals and the autonomic nervous system coexist and interact, creating a complex "neuro-endocrine cardiovascular process" which may account for many of the symptoms otherwise unexplained on the basis of the valvular abnormality alone.     

Mitral valve prolapse: a review of associated arrhythmias.

The syndrome of mitral valve prolapse with associated auscultatory-electrocardiographic findings is now well documented. Two representative cases of repetitive tachyarrhythmias in patients with mitral valve prolapse are discussed as well as an analysis of the 589 cases in the English literature of arrhythmias in patients with mitral valve prolapse. The average age of the patients was 38 years; 70 per cent of them were women. Symptoms were variable, but palpitations occurred in 44 per cent, lightheadedness in 12 per cent and syncope in 4 per cent. Premature atrial and/or ventricular contractions were found in 55 per cent, premature ventricular contractions in 45 per cent, supraventricular tachycardia in 6.1 per cent and ventricular tachycardia in 6.3 per cent. Sudden death was noted in 1.4 per cent. A discussion of the pathogenesis of arrhythmias and therapy concludes this review.     

Mitral valve prolapse

Mitral valve prolapse is a common valvular abnormality that is the most common cause of severe non-ischaemic mitral regurgitation in the USA. The overall prognosis of patients with mitral valve prolapse is excellent, but a small subset will develop serious complications, including infective endocarditis, sudden cardiac death, and severe mitral regurgitation. We present a comprehensive review of mitral valve prolapse, examining normal mitral anatomy, the clinical and echocardiographic features of mitral valve prolapse, and the pathophysiology and genetics of the disorder. We discuss the contemporary management of both asymptomatic and symptomatic prolapse, with particular attention to the timing and technique of surgical repair. We conclude that echocardiography is the method of choice for diagnosing mitral valve prolapse, that clinical and echocardiographic features can predict which patients with prolapse are at highest risk for complications, and that mitral valve repair is the treatment of choice for symptomatic prolapse.     

Mitral valve prolapse

Mitral valve prolapse has previously been found to be associated with severe cardiovascular complications such as embolic insults, infectious endocarditis, and sudden cardiac death. However, at the same time, in particular after adopting M-mode and 2D echo for diagnosis, prevalence of the disease was found to be very high, especially in the young. The dilemma of a disease which is frequent and mostly asymptomatic, but in some cases has catastrophic complications, has been solved by implementation of more restrictive diagnostic criteria based on an appreciation of the spatial morphology of the mitral annulus. These criteria call for diagnosis exclusively based on long axis views and a prolapse of > 2 mm beyond a line connecting the leaflet insertion points. "Classic prolapse" additionally requires diastolic thickness of the mitral leaflets of at least 5 mm. Two recent studies, a population-based study of mitral valve prolapse prevalence, and a case-control study of juvenile stroke patients compared to a group of young patients without a history of stroke, shed further light on this disease. The authors found that prevalence of mitral valve prolapse in an average population is 2-3% (1.3% for classic prolapse), without age or sex preponderance; the rate of cerebrovascular insults, congestive heart failure, and atrial fibrillation of patients with prolapse does not exceed that of the rest of the population; however, mitral insufficiency is more frequent; young patients with a history of cerebrovascular insult do not have higher mitral valve prolapse rates than young patients without previous insult.