CORRELATION BETWEEN THE EXERCISE-INDUCED INCREASE IN LEFT-VENTRICULAR FILLING PRESSURE AND THE EXTENT OF ISCHEMIC OR INFARCTED MYOCARDIUM

We investigated the correlation between left ventricular filling pressure and the extent of ischemic or infarcted myocardium in 39 patients with coronary artery disease: 25 with angina pectoris (group A) and 14 with old myocardial infarction but without overt transient myocardial ischemia (group B). Hemodynamic parameters were measured at rest and during exercise. The extent and severity scores of ischemia or infarct were calculated using thallium-201 (Tl-201) myocardial single-photon emission computed tomography. In group A, the extent and severity scores of ischemia were strongly correlated with pulmonary artery wedge pressure at peak exercise (r=0.71, p<0.001, r=0.62, p<0.01, respectively). In group B, the extent and severity scores of the infarct were significantly correlated with left ventricular ejection fraction (r=-0.81, p<0.001, r=-0.77, p<0.01, respectively), but were not correlated with pulmonary artery wedge pressure. Since no relationship was found between the extent of infarct and left ventricular filling pressure, dynamic exercise appears to elicit a different compensatory mechanisms in nonischemic myocardium for exercise-induced transient ischemia and in noninfarcted myocardium for old infarction. The compensatory mechanism in patients with old myocardial infarction may be affected by ventricular remodeling.