RATE OF CHANGE OF LEFT-VENTRICULAR EJECTION FRACTION DURING EXERCISE IS SUPERIOR TO THE PEAK EJECTION FRACTION FOR PREDICTING FUNCTIONALLY SIGNIFICANT CORONARY-ARTERY DISEASE

Objective-To detect and characterise rapid temporal changes in the lef t ventricular response to exercise in patients with ischaemic heart di sease and to relate these changes to the functional severity of corona ry artery disease. Background-The gamma camera does not allow the dete ction of rapid changes in cardiac function during exercise radionuclid e ventriculography, the monitoring of which may improve the assessment of patients with ischaemic heart disease. Methods-A miniature nuclear probe (Cardioscint) was used to monitor continuously left ventricular function during exercise in 31 patients who had coronary angiography for suspected coronary artery disease. A coronary angiographic jeopard y score was calculated for each patient. Results-The coronary jeopardy score ranged from 0 to 12 (median 4). Ejection fraction fell signific antly during exercise from 46% to 34%. Patients were divided into two groups based on the response of their ejection fraction to exercise. I n 14 patients (group I), the peak change in ejection fi action coincid ed with the end of exercise, whereas in the other 17 patients (group I I) the peak change in ejection fraction occurred before the end of exe rcise, resulting in a brief plateau. The peak change in ejection fract ion and the time to its occurrence were independent predictors of coro nary jeopardy (r = -0.59, p < 0.001 for peak change and r = -0.69, p < 0.001 for time to that change). The rate of change in ejection fracti on was the strongest predictor of coronary jeopardy (r = -0.81, p < 0. 001). In group I the peak change in ejection fraction was a poor predi ctor severity of coronary disease (r = -0.28, NS), whereas the time to peak and the rate of change in ejection fraction were good predictors (r = -0.65 and r = -0.73, p < 0.01). In group II the peak, the time t o the peak, and the rate of change in ejection fraction were good pred ictors of coronary jeopardy (r = -0.75, r = -0.61, and r = -0.83, p < 0.01). Conclusion-The rate of change of ejection fraction during exerc ise can be assessed by continuous monitoring of left ventricular funct ion with the nuclear probe, and is the best predictor of functionally significant coronary artery disease.