Usefulness of two-dimensional echocardiography during low-level exercise testing early after uncomplicated acute myocardial infarction

Abstract

To determine whether 2-dimensional (2-D) echocardiographic measures of segmental and global left ventricular (LV) function immediately on recovery of low-level, symptom-limited treadmill exercise are as sensitive as the same variables measured at peak bicycle exercise, 21 patients were studied after acute myocardial infarction (AMI). The recovery treadmill ejection fraction analysis was predictive of the peak bicycle results in 18 of the 21 patients (86%) and recovery treadmill wall motion abnormalities were predictive of the peak bicycle analysis in 17 (81%) (p < 0.01). These data indicate that 2-D echocardiography during the immediate recovery phase of low-level post-infarction treadmill testing was as sensitive as the peak exercise assessment of segmental and global LV function. Accordingly, the predictive value of rest and recovery exercise measures were prospectively assessed in 67 patients during a mean follow-up interval of 11 months (range 3 to 24). Clinical characteristics and treadmill electrocardiographic findings did not identify the 16 of 67 patients (24%) who had new cardiac events (3 cardiac deaths, 8 recurrent AMIs and 6 coronary artery bypass graft operations). However, a decrease in recovery ejection fraction units of more than 10% was seen in 7 of these 16 patients (44%) with events, compared with only 4 of the 51 (13%) without events (p < 0.002), and new or worsening wall motion abnormalities on exercise recovery were seen in 10 of the 16 patients (63%) with events, but in only 10 of the 51 (20%) without (p <0.001). A multivariate logistic regression analysis identified, in order of significance, wall motion abnormalities on recovery of exercise (p < 0.001), angina pectoris during treadmill exercise (p < 0.04) and rest ejection fraction (p < 0.04) as predictors of future cardiac events. Thus, 2-D echocardiography during the recovery phase of low-level post-AMI treadmill exercise testing is as sensitive as the peak exercise assessment of segmental and global LV function; and a decrease in ejection fraction units of more than 10 % or new or worsening wall motion abnormalities on recovery of exercise identify a significant number of patients with uncomplicated infarction at high risk for cardiac events.