Vagal stimulation of the hea causes:

Increased R-R interval in ECG Vagus is the parasympathetic supply to the hea. Its stimulation causes: - Decreased hea rate - Decreased force of hea contraction - Decreased cardiac output R-R interval is the time interval between consecutive hea beats in the electrocardiogram. So a decrease in hea rate increases the R-R interval Reverse effects on the hea are noted due to sympathetic stimulation.