Blood velocity at mitral valve during atrial arrhythmias in man.

By means of the Doppler ultrasonic flowmeter catheter, phasic instantaneous left ventricular blood velocity was measured at the mitral valves of 184 conscious human subjects during atrial arrhythmias. Atrial extrasystoles and pacemaker-induced atrial tachycardias reduced peak mitral valve blood velocities in direct relation to shortened diastolic cycle length. Atrial fibrillation with irregular ventricular responses produced beat-to-beat alternations of peak mitral velocity, with smaller peak mitral blood velocities usually associated with shortened R-R intervals on the electrocardiogram. This report represents the first comprehensive description of instantaneous and continous phasic blood velocity at the mitral valve during atrial arrhythmias in man. It is concluded that atrial tachyarrhythmias exert an adverse influence on left ventricular filling velocities.