Hemodynamic results of right atrial pacing in 33 normal subjects.

The effect of increasing heart rate above control sinus rate was studied in 33 normal subjects by right atrial bipolar electrode catheter pacing. At all atrial pacing rates, significant cardiac output increments are noted compared to the outputs during the control sinus rate. Further heart rate elevation produced by electrical pacing fails to elevate cardiac output above the levels noted at the lower atrial pacing rates.