Close coupling of systolic and diastolic function: combined assessment provides superior prediction of exercise capacity.

BACKGROUND: Isolated diastolic dysfunction is thought to account for approximately 50% of cases of heart failure. We tested the hypotheses that (1) the use of different methods for assessing systolic and diastolic function may contribute to the apparent frequency with which they are dissociated and (2) that combined assessment of systolic and diastolic function is superior to either one alone.

METHODS AND RESULTS: A total of 110 patients underwent echocardiography with tissue Doppler imaging (TDI) of the mitral annulus before maximal exercise testing. The correlation between left ventricular (LV) ejection fraction (EF) and exercise capacity was weak (r = 0.199). Among patients with EF greater than 55%, those with normal exercise capacity (>7 METs) had a higher systolic velocity of the mitral annulus than those achieving less than 7 METs (9.6 +/- 0.3 versus 7.5 +/- 0.4 cm/s, P = .001). The mitral annular systolic (Sa) and early diastolic (Ea) velocities each correlated moderately with exercise tolerance (r = 0.40 and 0.49, respectively). Sa and Ea correlated highly with each other (r = 0.79, P < .001). The sum of isovolumic contraction and relaxation times measured from TDI correlated moderately with exercise duration (r = -0.59). A combined index of systolic and diastolic function that includes isovolumic contraction and relaxation times and ejection time had the best correlation with achieved METs (r = -0.73, P < .001). A TDI index of cardiac performance higher than 0.52 had excellent sensitivity (86%) and specificity (100%) for predicting reduced exercise tolerance lower than 7 METs.

CONCLUSION: When assessed with the same technique, LV systolic and diastolic function are tightly linked. A TDI-derived combined index of myocardial performance is the best predictor of exercise capacity.