BACKGROUND: To determine sensitivity and specificity of E wave velocity in patients with severe chronic organic mitral regurgitation (MR) and normal left ventricular ejection fraction (EF) and to evaluate prevalence of A wave dominance in patients with severe MR. METHODS: We compared 35 patients with quantified severe, chronic, quantified, organic MR due to flail/prolapsed leaflets who had reparative surgery with 35 age-matched control subjects. Exclusion criteria: EF < 60%, atrial fibrillation, and more than mild aortic regurgitation. RESULTS: Mean [standard deviation (SD)] age [70 (8) years vs. 69 (8) years; p = 0.94] and mean (SD) EF [66% (6%) vs. 65% (4%); p = 0.43] were not different between the two groups. Mean (SD) E wave velocity was greater in case patients than control subjects [1.2 (0.3) m/sec vs. 0.7 (0.15) m/sec; p < 0.001]. However, E wave velocity of 1.2 m/sec had a sensitivity of only 57% [95% confidence interval (CI), 41-7 and a specificity of 100% (95% CI, 90-100%) in identifying severe MR. E wave velocity of 0.9 m/sec had a more optimal combined sensitivity (89%; 95% CI, 74-95%) and specificity (86%; 95% CI, 71-94%). A wave dominance was seen in 18% of case patients and 66% of control subjects (p < 0.001). CONCLUSION: E wave velocity of 1.2 m/sec is specific not sensitive for severe organic MR; E wave velocity of 0.9 m/sec has better sensitivity and specificity. A wave dominance pattern alone cannot exclude patients with severe organic MR. Our findings highlight the importance of a comprehensive echocardiographic exam rather than relying on a few Doppler parameters in diagnosing MR.