In patients with chronic heart failure (CHF) and severe secondary mitral regurgitation (MR), the diagnostic usefulness and prognostic impact of tissue Doppler imaging (TDI) is unknown. This prospective study enrolled 370 patients with stable CHF. Severe secondary MR, defined as effective regurgitant orifice area >/=0.20 cm(2), was present in 92 patients (25%). Echo measurements comprised left ventricular volumes, ejection fraction, mitral E/A ratio, deceleration time, and TDI-derived mitral annular velocities (e.g., S', E', A', E/E'). During a follow-up of 790 +/- 450 days, all-cause mortality and rehospitalization data were analyzed. Patients with or without MR did not differ with respect to age or ejection fraction, but patients with MR were in a poorer New York Heart Association functional class and had a higher mitral E/E' ratio. During follow-up, 70 patients (18%) died and 134 patients (36%) were rehospitalized for worsening heart failure. Mortality rate was significantly higher in patients with versus without severe MR (33% vs 14%, p <0.001). In the MR group, the mitral E/E' ratio independently predicted all-cause mortality and was also significantly associated with rehospitalization for worsening heart failure. In patients with MR with an E/E' ratio >13.5, outcome was markedly worse compared with patients with an E/E' ratio </=13.5 (event-free survival rate, 64% vs 31%, p <0.001). In conclusion, in patients with CHF and severe secondary MR, a higher mitral E/E' ratio is associated with increased morbidity and an adverse outcome. TDI appears to be a useful adjunct in the diagnostic workup and risk stratification of such patients.