Left ventricular ejection fraction changes during recovery from treadmill exercise: A preliminary report of a new method for detecting coronary artery disease

To test the value of combining treadmill exercise with radionuclide angiography for detecting exercise-induced left ventricular dysfunction, ejection fractions were calculated at rest, peak supine bicycle exercise, and during three supine post-treadmill recovery periods (2-4 min, recovery 1;4-6 min, recovery 2;8-10 min, recovery 3) in ten coronary artery disease patients and eight normal subjects. Both the normal subjects and coronary artery disease patients had normal resting ejection fractions (greater than 0.50). In the normal subjects the mean ejection fraction increased significantly (p less than 0.005) from rest (0.61 +/- 0.03) to peak supine bicycle exercise (0.71 +/- 0.04), and the mean ejection fraction also remained significantly higher (p less than 0.005) at rest than during 10 min post-treadmill exercise. However, the coronary artery disease patients did not significantly change the mean ejection fractions from rest (0.59 +/- 0.06) to peak supine bicycle exercise (0.55 +/- 0.08), and the average ejection fraction during each one of the post-treadmill recovery periods was not significantly different from rest. At the third recovery period all the normals but no coronary artery disease patients had higher ejection fraction than the resting ejection fraction. We thus conclude that the magnitude of change in ejection fraction from rest to 8-10 min post-treadmill exercise in patients with normal resting ejection fraction may be helpful in identifying those with coronary disease.