Key Learning Points
Respiratory Sinus Arrhythmia
Introduction Page 1
- Respiratory Sinus Arrhythmia (RSA) is defined as a slight variation in the regularity of a sinus rhythm, usually one that exceeds 0.12 seconds between the longest and shortest cycles.
- RSA is a normal and benign finding in children and young adults(a) and tends to diminish or disappear with age(b).
- RSA occurs primarily through respiratory influence on the vagal nerve.
- RSA is becomes more apparent with slower heart rates. As the heart increases the vagal influence tends to decrease.
Inspiratory Effect on the Sinus Node Page 2
- Inspiration causes slightly decreased blood pressure, which decreases vagal impulse to the heart, thereby increasing the heart rate.
