Phasic coronary arterial flow velocity during arrhythmias in man

Abstract

The influence of cardiac arrhythmias on coronary arterial flow velocity studied by means of a Doppler catheter flowmeter system is described in 47 patients. The arrhythmias examined included atrial and ventricular extrasystoles, atrial fibrillation, pacemaker-induced atrial tachycardia, paroxysmal atrial tachycardia, ventricular tachycardia, Wenckebach second degree atrioventricular block and complete heart block. In atrial and, less frequently, in ventricular extrasystolic beats, peak coronary arterial flow velocity did not change significantly when the preceding R-R interval was greater than 0.50 second. However, when this interval was shorter than 0.50 second, a proportional decrease in peak coronary arterial flow velocity occurred. Variations in beat to beat coronary arterial flow velocity were seen uniformly in patients with atrial fibrillation. However, there was no correlation between peak coronary arterial flow velocity and the preceding R-R interval; in addition, no correlation was found between peak coronary arterial flow velocity and the same cycle length. In pacemaker-induced atrial tachycardia, decreased peaked coronary arterial flow velocity was observed at pacing rates greater than 140/min. In 1 patient with paroxysmal atrial tachycardia with an atrial rate of 200/min, there was a marked decrease and irregularity in coronary arterial flow velocity. The more abrupt decrease in flow velocity occurred in ventricular tachycardia. In Wenckebach second degree atrioventricular block, no measurable coronary arterial flow velocity was observed in the cycle encompassed by the dropped beat. However, the total area under the velocity curve was greater in the pre-dropped atrial beat than in other beats. In patients with complete heart block, the systolic component of flow velocity was greater than in patients in sinus rhythm.