Background: Triphasic mitral inflow with the L wave has been recognized as a marker of advanced diastolic dysfunction. Although, not infrequently, mid-diastolic mitral annular velocity (L���) can be observed in these patients, the clinical impact of the presence of L��� wave is poorly understood. The purpose of this study was to evaluate the effects of the presence of L��� wave on clinical outcome in patients with triphasic mitral inflow pattern. Methods: Between February 2003 and September 2007, a total of 185 patients with triphasic mitral inflow pattern, including mid-diastolic flow (L) of ��� 0.2 m/s, and in sinus rhythm were prospectively identified. Primary end-points were a composite of cardiovascular mortality and hospitalization for HF. Results: Median follow-up duration was 36 months (range: 0-64 months). L��� wave was present in 105 (56.8 %) and absent in 80 (43.2 %) patients. Patients with L��� wave showed higher BNP levels, left ventricular (LV) mass index, and left atrial (LA) volume index. In tissue Doppler imaging, patients with L��� wave showed lower E��� wave velocity, higher E/E��� ratio and higher mitral L wave velocity. During follow-up, total events of cardiovascular deaths and hospitalization for HF occurred in 28 (15.1 %) patients. Among the predictors that showed a significance in the multivariate Cox analysis, including age, Killip class, renal insufficiency, and mitral regurgitation (grade ��� II), the presence of L��� wave was the most independent predictor of adverse outcome in these patients. Conclusion: In patients with triphasic mitral inflow pattern, the presence of L��� wave indicates more advanced diastolic dysfunction and predicts the adverse outcomes over the established surrogate markers of diastolic dysfunction. The detection of an L��� wave in patients with triphasic mitral flow may have important implications for prognosis and therapy.