What is respiratory sinus arrhythmia?

What is respiratory sinus arrhythmia?

Heart rate increases in inspiration (breathing in) and decreases in expiration (breathing out). This can be accurately identified while monitoring the pulse rate / ECG. The output of the left ventricle is lower in inspiration. This triggers a compensatory increase in heart rate. The reverse occurs in expiration. This change is known as respiratory sinus arrhythmia.