Exercise-induced changes of left ventricular ejection time in noninvasive evaluation of chest pain

Significance and clinical usefulness of exercise-induced changes of noninvasive left ventricular ejection time, recorded by mechanocardiography, in detecting coronary artery disease is still controversial. We investigated the changes of the left ventricular ejection time (LVET), corrected for heart rate as ETI (LVET/square root RR), after a standard 4-min exercise by bicycle ergometer (50 W/min for 2 min, increased by 20 W after 2 min) in 56 male volunteers. They were invasively studied for typical or atypical chest pain. Thirty-four had coronary artery disease (CAD) and the others served as controls. Immediately after exercise LVET shortened according to the rise in heart rate in both groups. ETI increased similarly. After 2 minutes from exercise ETI increased only in the CAD group, according to a longer LVET, in spite of the rise in heart rate. In contrast, ETI was unchanged in controls, according to a shortened LVET. Totally, 27/34 CAD patients and 9/22 controls had a greater ETI than at rest. Employing this delta ETI as a "marker" of CAD we found a predictive accuracy of 74%. We suggest postexercise ETI could be a simple and inexpensive support to electrocardiogram in basic evaluation of subjects with chest pain.