[Serial assessment of cardiac function during and after exercise by an ambulatory ventricular function monitor...

Cardiac function was serially assessed during and after exercise by an ambulatory ventricular function monitor (VEST) in 31 patients who received coronary angiography. Based on the study of fluctuation during the baseline recording, greater than or equal to 6% change in ejection fraction (EF) was considered significant. The serial changes in EF during exercise was divided into 5 types, including continuous increase (type A), initial increase but return to the baseline (type B), no change (type C), initial increase but later decrease below the baseline (type D), and continuous decrease (type E). Among 8 normal subjects, their EF changes during exercise showed type A in 3, type B in 2, type C in 2, and type D in 1. Among 21 patients with coronary artery disease, the EF changes showed type A in 5, type B in 4, type C in 4, type D in 5 and type E in 3. Thus, there was a significant overlap in EF response between normal and coronary patients. However, every patient showing type A and B had single-vessel disease, and 63% of them had persistent thallium defect without redistribution. After the exercise, 29 patients showed rapid increase in EF. The time to the peak EF was significantly longer in coronary patients (1.88 +/- 1.24 min) than that in normal cases (0.88 +/- 0.55 min) (p less than 0.05) particularly in patients with multi-vessel disease (2.22 +/- 1.29 min). In addition, those showing type C, D or E tended to have a longer time to peak EF and more increase in EF after exercise than those showing type A or B. These data suggest that VEST is suitable for continuous measurement of cardiac function during and after exercise which provided valuable indices for assessment of severity of ischemia in coronary artery disease.