Mitral valve prolapse with a late-systolic regurgitant murmur may be associated with significant hemodynamic consequences.

The late-systolic murmur of mitral regurgitation (MR) in degenerative mitral valve disease is widely believed to represent regurgitation of a degree that is not associated with hemodynamic significance. However, the extent of left ventricular (LV) remodeling associated with the late-systolic murmur has not been systematically assessed. Accordingly, we studied 82 patients sent for evaluation of at least moderate isolated MR by echocardiography/Doppler examination. All patients had a physical examination and cardiac magnetic resonance imaging to measure LV volumes by summation of serial short-axis slices. Forty-five patients had a pan-systolic murmur and 37 had a late-systolic murmur on auscultation that was verified by timing of onset of regurgitant turbulence by cine magnetic resonance imaging. Systolic blood pressures (124 +/- 3 versus 124 +/- 3 mm Hg) and LV ejection fraction (61 +/- 1% versus 61 +/- 1%) did not differ significantly between pan-systolic and late-systolic murmur groups. Although LV end-diastolic volume index was greater in the pan-systolic versus late-systolic murmur (108 +/- 4 versus 95 +/- 4 mL/m2, P = 0.007), both groups were significantly greater than normals (68 +/- 2 mL/m2, P < 0.0001). However, LV end-systolic volume index (42 +/- 2 versus 38 +/- 2 mL/m2) and LV end-systolic dimension (38 +/- 1 versus 37 +/- 1 mm), critical markers of adverse LV remodeling in isolated MR, did not differ significantly between pan-systolic and late-systolic murmur groups. In conclusion, the late systolic isolated MR murmur may be associated with significant adverse LV remodeling, and should not be considered evidence of hemodynamically unimportant MR.