The effects of ventricular tachycardia on carotid artery blood flow velocity.

The Effects of Ventricular Tachycardia on Carotid Artery Blood Flow Velocity • Utilizing the Doppler flowmeter catheter, right carotid blood velocity was measured during episodes of catheter-evoked and pacemaker-induced ventricular tachycardias. Such tachyarrhythmias uniformly diminished peak carotid blood velocity, which in the case of catheter-evoked episodes reduced phasic blood velocity by 50%. At driving rates greater than 140 per minute, the average peak carotid blood velocity was 25% to 50% lower during ventricular when compared with atrial pacing. There was a direct correlation between the ventricular pacing rates and the percent decline of peak carotid blood velocity. Such arrhythmiarelated carotid blood velocity deficits may account for syncopal episodes in subjects so affected. Additional