Background: The mechanisms that determine reduced exercise capacity after acute myocardial infarction (AMI) are not fully understood, especially the relative role of left ventricular diastolic and systolic function.
Hypothesis: To evaluate the role of different diastolic and systolic function echocardiographic parameters as predictors of reduced functional capacity in patients after AMI.
Methods: One month after AMI, 225 patients (84% male; mean age, 55.1 ± 10.9 years) were enrolled and underwent detailed echocardiography and cardiopulmonary exercise test on the same day. Systolic and diastolic function was evaluated by echocardiography according to the latest consensus recommendations, including tissue Doppler evaluation. Exercise capacity was evaluated with peak oxygen consumption (VO(2)).
Results: Peak VO(2) was significantly correlated with early diastolic tissue Doppler velocity (E') septal (r = 0.42, P < 0.001), E' lateral (r = 0.35, P < 0.001), septal E/E' ratio (r = -0.35, P = 0.001), and lateral E/E' (r = -0.27, P < 0.001). These diastolic function parameters predicted impaired exercise capacity (VO(2) <19 mL/kg/min), with an area under the receiver operating characteristic curve of 0.77 (95% confidence interval [CI]: 0.68-0.86, P < 0.001) for septal E/E'. On multivariate analysis, for each unit increase in septal E/E' ratio there was a -0.35 (95% CI: -0.54 to -0.15) mL/kg/min decrease in peak VO(2) independently of age, sex, body mass index, hypertension, and diabetes. There was a mild correlation between peak VO(2) and systolic function parameters (r = 0.17, P = 0.01 with ejection fraction; and r = 0.23, P = 0.02 with lateral systolic tissue Doppler velocity) that persisted after multivariate adjustment.
Conclusions: After AMI, resting diastolic function parameters were the strongest correlates of exercise tolerance. Septal E/E' ratio was the best echocardiographic predictor of reduced functional capacity.
© 2015 Wiley Periodicals, Inc.