Effect of pacing-induced tachycardia and myocardial ischemia on ventricular pressure-velocity relationships in man.

Ventricular function was evaluated in 18 patients prior to left ventriculography and selective coronary arteriography. Simultaneous left ventricular pressure (catheter-tip manometer) and dP/dt were recorded at resting heart rates and during tachycardia induced by right atrial pacing. Pressure-velocity curves were constructed from which Vmax and maximum measured contractile element velocity (max VCE) were obtained. Vmax and max VCE initially increased with pacing-induced tachycardia in 17 of the 18 patients. Eight patients developed evidence of myocardial ischemia during atrial pacing. During the period of myocardial ischemia there was a decrease in Vmax and