SILENT LEFT-VENTRICULAR DYSFUNCTION DURING ROUTINE ACTIVITY AFTER THROMBOLYTIC THERAPY FOR ACUTE MYOCARDIAL-INFARCTION

To investigate prospectively the occurrence and significance of postinfarction transient left ventricular dysfunction, 33 ambulatory patients who underwent thrombolytic therapy after myocardial infarction were monitored continuously for 187 ± 56 min during normal activity with a radionuclide left ventricular function detector at the time of hospital discharge. Twelve patients demonstrated 19 episodes off transient left ventricular dysfunction (>0.05 decrease in ejection fraction, lasting ≥ 1 min), with no change in heart rate. Only two episodes in one patient were associated with chest pain and electrocardiographic changes. The baseline ejection fraction was 0.52 ± 0.12 in patients with transient left ventricular dysfunction and 0.51 ± 0.13 in patients without dysfunction (p = NS). At follow-up study (19.2 ± 5.4 months), cardiac events (unstable angina, myocardial infarction or death) occurred in 8 of 12 patients with but in only 3 of 21 patients without transient left ventricular dysfunction (p < 0.01). During submaximal supine bicycle exercise, only two patients demonstrated a decrease in ejection fraction >0.05 at peak exercise; neither had a subsequent cardiac event. These data suggest that transient episodes of silent left ventricular dysfunction at hospital discharge in patients treated with thrombolysis after myocardial infarction are common and associated with a poor outcome. Continuous left ventricular function monitoring during normal activity may provide prognostic information not available from submaximal exercise test results. © 1990.