Hemodynamic accompaniments of angina: a comparison during angina induced by exercise and by atrial pacing.

The hemodynamic responses of nine patients with severe coronary artery disease were studied during the precipitation of angina by both supine exercise and increasing rates of atrial pacing. Tension-time index and the first derivative of left ventricular pressure pulse (LV dp/dt) at the onset of angina were significantly higher (P < 0.01) in each patient when angina was induced by exercise than when angina was provoked by atrial pacing. Heart rate, in contrast, was significantly greater (P < 0.05) when angina was precipitated by atrial pacing. Left ventricular end-diastolic pressure (LVEDP) was abnormally elevated in each patient when angina occurred during supine exercise, whereas LVEDP was normal in all patients at the onset of angina provoked by atrial pacing. On the basis of these results it appears that the hemodynamic accompaniments of angina depend to a large extent on the particular circumstances leading to the development of angina. Tension-time index, LV dp/dt, and heart rate are major determinants of myocardial oxygen consumption, and the interrelationships between the determinants of myocardial oxygen consumption are complicated. Thus, changes in any one of these determinants after a therapeutic intervention must be viewed in relation to possible changes in the others.