Baroreflex modulation of ventricular rhythm in atrial fibrillation.

The influence of bilateral carotid sinus nerve stimulation was studied in a patient with atrial fibrillation. Stimulation resulted after approximately 1.5 s in abrupt prolongation of the minimum, median and maximum RR-interval, and in greater RR-interval dispersion. Virtually no change was observed in the random character of the ventricular rhythm. The absence of demonstrable baroreflex modulation of the ventricular rhythm in atrial fibrillation is probably due to the relatively long latency of the reflex effect on atrioventricular conduction in relation to the duration of the RR-intervals.