Hemodynamic effects of tachycardias produced by atrial and ventricular pacing

The hemodynamic effects of right atrial and ventricular bipolar catheter pacing were investigated in fifty-four subjects in sinus rhythm. Right and left heart pressures were measured, and cardiac outputs determined by the indicator dilution method, at both control sinus rates and during atrial and ventricular tachycardias at varying rates above the control sinus rate, induced by atrial and ventricular catheter electrodes. The results of this study clearly demonstrate that, in intact man, ventricular pacing, at ventricular rates similar to those induced by atrial pacing, result in decrements in cardiac output and in systemic arterial pressures, together with atrioventricular regurgitation. The application of these data to synchronous or idioventricular pacing in patients in complete heart block seems evident.