Spectrum of heart rate variability

Summary form only given. To test the hypothesis that patients with advanced structural disease and congestive failure have intermediate heart rate variability (HRV) values, the authors compared HRV in 33 young healthy subjects without evidence of heart disease, 23 patients with ischemic heart disease complicated by stable NYHA class II-III heart failure (CHF), and 13 patients who died during Holter monitoring (sudden cardiac death-SCD). Five CHF patients died after 9±5 months (CHF/D). Two HRV measures, SDANN (standard deviation (SD) of the mean of sinus R-R intervals (R-R) for successive 5-minute periods over 24 h) and SD (mean of SD of R-R for successive 5-min periods over 24 h) were determined from 24-h Holter records. Group differences were tested by analysis of variance. The data suggest that there is a spectrum of HRV that is highest in normal young subjects, lowest in SCD patients, and intermediate in the CHF group. However, HRV values in all CHF/D patients approximated those for SCD patients, suggesting that progression of disease and increasing risk of dying are associated with a decline in HRV. HRV measures may thus provide a tool for monitoring mortality increase in patients with heart disease