Slowed heart rate (HR) recovery after exercise is strongly predictive of increased long-term mortality. The factors responsible for impaired HR regulation are not fully understood. We performed echocardiography with tissue Doppler imaging in 121 patients before maximal exercise testing. HR recovery was measured 1 minute after the end of exercise in the supine position. The best echocardiographic correlate of HR recovery was the ratio of early mitral flow velocity (E) to early diastolic mitral annular velocity (Ea; r = −0.781, p <0.001). This correlation was not affected by the use of negative chronotropic agents. Patients whose E/Ea was <10 had a faster 1-minute HR recovery and a greater chronotropic response during exercise than did those whose E/Ea was ≥10. Receiver-operator characteristic analysis showed that an E/Ea ≥10.3 predicted 1-minute HR recovery of ≤18 beats/min, with 83% sensitivity and 100% specificity. Neither left ventricular ejection fraction nor the presence of a “slow relaxation” mitral inflow pattern (E/A <1.0) was predictive of impaired HR recovery. Thus, slowed HR recovery is strongly associated with increased E/Ea, a marker of increased left ventricular filling pressures. E/Ea at rest may become a simple, reliable, and sensitive predictor of increased long-term mortality, even in the absence of overt heart failure.