|Unadjusted Model||Adjusted Model|
|aHR||95% CI||p Value||aHR||95% CI||p Value|
|Heart rate on resting ECG||1.03||1.02–1.04||<0.001||1.03||1.02–1.04||<0.001|
|Systolic blood pressure||1.01||1.004–1.015||0.001||1.01||1.004–1.016||0.001|
|ln (PVC + 1)||1.12||1.07–1.19||<0.001|
Turbulence onset indicates a signal average of the magnitude of tachycardia, if any, as the percentage of change in N–N interval of the sinus rhythm 2 beats after the premature ventricular contraction (PVC) compared with the 2 beats before. Although calculation of HRT requires at least 5 qualifying PVCs, when HRT is categorized, participants with fewer than 5 PVCs can be categorized as having normal heart rate variability and are therefore included in the analysis. Very low frequency power indicates variance in heart rate variability at underlying frequencies of every 25 s to every 5 min calculated for every 15-min segment and averaged.
CV (%) = average coefficient of variance of N–N intervals for 5-min segments for 24 h; DFA1 = short-term fractal scaling exponent calculated over 3 to 11 beats and averaged over 1,000 beats for 24 h; ECG = electrocardiogram; Health ABC = Health Aging and Body Composition Heart Failure; ln (PVC + 1) = natural log transformation of the number of premature ventricular contractions + 1; ln (VLF24) = natural log transformation of very low frequency power which indicates variance in heart rate variability at underlying frequencies of every 25 s to every 5 min, calculated for every 15-min segment and averaged; other abbreviations as in Table 1.