Functional mitral regurgitation. Physiopathology and impact of medical therapy and left ventricular surgical reduction techniques

Functional mitral regurgitation is frequently observed in the setting of le ft ventricular dyfunction. This finding is a marker of poor outcome in pati ents with either ischemic or dilated cardiomyopathy. The mechanism accounting for this phenomenon is an altered balance of tethe ring versus coapting forces acting on the mitral valves in the failing hear t. Tethering forces represent an anomalous tension on the mitral valves due to displacement of mitral valve attachments secondary to increased left ventr icular chamber sphericity associated with systolic ventricular dysfunction. On the other hand, coapting forces are weak and unable to counteract the a bnormal tension acting on the mitral valve, which restricts closure and lea ds to regurgitation. Vasodilators and inotropic drugs are effective in the management of functio nal mitral regurgitation. Although partial left ventriculectomy or Batista' s procedure is still investigational, this new technique seems to provide a n optimal control of functional mitral regurgitation and improve Functional capacity and survival of some patients with heart failure.