Left ventricular dyssynchrony and functional mitral regurgitation: two dynamic conditions

Abstract

A 30-year-old-man was admitted to the hospital in NYHA class IV without any medical treatment. The coronary arteries were normal. Left ventricular (LV) ejection fraction (EF) was 30%, mean capillary wedge pressure was 38 mmHg. The QRS duration was 120 ms. Myocardial biopsy revealed signs of idiopathic cardiomyopathy without inflammatory infiltration. The patient was treated by lisinopril, carvedilol, and spironolactone and progressively improved. One month later, a Doppler echocardiogram revealed important LV dilatation and reduced EF of 21%. Severe mitral regurgitation (MR) was observed: the effective regurgitant orifice (ERO) was 30 mm2. Significant LV dyssynchrony was found: the difference between time to peak systolic velocities of septal and lateral segments was 170 ms and the standard deviation of time to peak systolic velocity of 12 LV segments was 98 ms. Surprisingly, cardiopulmonary exercise testing showed a normal VE/VCO2 slope and peak VO2 was 28 mL/kg/min. How can we explain the discrepancy between severe LV dysfunction and preserved exercise capacity? Exercise Doppler echocardiography was performed. An important decrease was observed during exercise in both the degree of functional MR (ERO = 10 mm2) and of LV dyssynchrony (septal to lateral delay = 20 ms). This case illustrates the dynamic characteristics of both functional MR and LV dyssynchrony. During exercise, MR may vary substantially with loading conditions that modulate mitral valve geometry, thus tethering … *Tel: +32 4 366 71 94; fax: +32 4 366 71 95. E-mail address : lpierard{at}chu.ulg.ac.be