Vagal stimulation of the hea causes all, EXCEPT:: (A) Decreased Hea Rate, (B) Decreased force of Hea contraction, (C) Decreased Cardiac Output., (D) Decreased R-R interval in ECG
Answer is D. Parasympathetic supply to the hea by vagus nerve causes decreased hea rate, decreased force of contraction, decreased cardiac output. R-R interval is the time interval between consecutive hea beats in the ECG. So a decrease in hea rate increases the R-R interval.