Vagal stimulation of hea causes? (irrelevant to pharmacology): (A) Increased hea rate, (B) Increased RR interval in ECG, (C) Increased cardiac output, (D) Increased force of contraction
Answer is B. Increased RR interval is seen in ECG on vagal stimulation. Normal values for waves and intervals are as follows: RR interval: 0.6-1.2 seconds. P wave: 80 milliseconds. ... QT interval: 420 milliseconds or less if the hea rate is 60 beats per minute (bpm) Ref: KD Tripathi 8th ed.