Heart rate variability

Uncommon card · No. 149046

Heart rate variability (HRV) is the physiological phenomenon of variation in the time interval between heartbeats. It is measured by the variation in the beat-to-beat interval. Other terms used include cycle length variability, R–R variability (where R is a point corresponding to the peak of the QRS complex of the ECG wave; and R–R is the interval between successive Rs), and heart period variability. Measurement of the R–R interval (often termed normal-to-normal or N–N interval when additional filtering is used) is used to derive heart rate variability. Methods used to detect beats include ECG, blood pressure, ballistocardiograms, and the pulse wave signal derived from a photoplethysmograph (PPG). ECG is considered the gold standard for HRV measurement because it provides a direct reflection of cardiac electric activity.

Read on Wikipedia · Image George Billman, Attribution