Analysis of 24 hour heart rate variability in post-infarction patients

Summary form only given. The 24-h heart rate variability (HRV) in 40 Holter tapes from the Multicenter Post-Infarction Research Group Study was examined. The first 20 Holters were part of a preliminary study which analyzed various time- and frequency-domain measures of HRV. The time-domain measures were based on the RR intervals and included the 24-h standard deviations of RR/sub n/ and RR/sub n-1/-RR/sub n/. The frequency-domain measures were based on a single 24-h HR spectrum and included the LO (0.01-0.15-Hz) power, HI (0.15-0.50-Hz) power, and the alpha , which characterized the low-frequency 1/f/sup alpha / tail of the power spectrum. The other 20 Holter tapes were used to see whether the HRV measures could be used as predictors of mortality. It was found that HI power and total HRV power clearly separated the 20 patients into two distinct groups of 10 patients each. However, belonging to a group was completely unrelated to mortality: half the members of each group died.<>