THE PATHOPHYSIOLOGY OF ARRHYTHMIC MITRAL VALVE PROLAPSE

It is estimated that the prevalence of mitral valve pro­lapse (MVP) among middle-aged and older individuals in Western countries is 2-4% (1). MVP can lead to va­rious adverse outcomes such as significant mitral valve dysfunction, heart failure, infective endocarditis, stroke, cardiac arrhythmias, and the least investigated but most severe complication, sudden cardiac arrest (2). In asses­sing the risk of life-threatening ventricular arrhythmias associated with arrhythmic mitral valve prolapse, several clinical factors stand out, most of which can be evalua­ted using non-invasive diagnostic methods. Characteris­tic risk factors include mitral annular anomalies (mitral annulus disjunction), left ventricular myocardial fibrosis, altered mitral annular velocity configuration, hypera­drenergic state, female gender, complex left ventricular ectopy, and changes in the electrocardiogram (T-wave inversions in inferior leads).

Mitral annulus disjunction (MAD) is a pathology often observed in patients with myxomatous MVP and is clo­sely associated with MVP (3). Recent studies have shown a connection between MAD, ventricular arrhythmias, and papillary muscle fibrosis (4, 5). It has been found that patients with MAD more commonly experience ventri­cular extrasystoles and ventricular tachycardia compared to those without MAD (4). Life-threatening ventricular arrhythmias associated with MVP are more common in women (data indicates that 70-90% of affected indivi­duals are women) (6). The cause of this gender misma­tch is unknown and may be multifactorial: both types of MVP are more common in women, and surgical mitral valve repair is less frequently performed in women (7).

In younger patients, the anatomic features of MVP arise from the formation of excess tissue on the MV leaflets, leading to Barlow’s disease, while in older patients, ana­tomic abnormalities typically manifest as fibroelastic degeneration. Both forms of the disease can cause elon­gation or rupture of the MVP chords (8). The aim of the study is to summarise the pathophysiology of mitral valve prolapse using literature sources.