Cardiology Research and Practice

Clinical Study

Heart Rate Variability after Off-Pump versus On-Pump Coronary Artery Bypass Graft Surgery

Table 2

Differences in heart rate variability between off-pump versus on-pump CABG patients.
HRV variablesOff-pump CABG Mean ± SDOn-pump CABG Mean ± SD 𝑃
Mean RR interval (milliseconds) 8 8 5 ± 1 0 6 8 7 9 ± 1 2 5 NS
SDNN (milliseconds) 1 0 7 ± 3 0 1 0 5 ± 3 4 NS
SDNN-i (milliseconds) 3 9 ± 1 4 4 1 ± 1 9 NS
SDANN-i (milliseconds) 9 6 ± 2 7 9 3 ± 3 2 NS
rMSSD (milliseconds) 2 4 ± 1 2 2 8 ± 1 8 NS
pNN50 (%) 4 . 8 ± 6 . 4 5 . 7 ± 8 . 1 NS
TP (ms2) 2 2 9 8 ± 2 4 7 2 2 1 5 6 ± 1 9 1 3 NS
VLF (ms2) 1 3 9 7 ± 1 1 1 7 1 3 4 5 ± 9 8 8 NS
LF (ms2) 3 0 2 ± 3 4 1 3 8 4 ± 4 0 9 NS
HF (ms2) 2 6 2 ± 2 9 2 2 1 6 ± 2 6 1 NS
LF/HF 2 . 7 ± 1 . 9 2 . 5 ± 1 . 8 NS
Mean RR—mean of R-R intervals for normal beats, SDNN-standard deviation of all normal R-R intervals, SDANN-i—standard deviation of the 5-minutes means of R-R intervals, SDNNi—mean of the 5-minute standard deviations of RR intervals, rMSSD—square root of the mean of the squared successive differences in R-R intervals and pNN50-percentage of R-R intervals that are at least 50 milliseconds different from the previous interval, TP—Total power (0.0–0.5 Hz), VLF—very low (0.003–0.04 Hz), LF—low (0.04–0.15 Hz) and HF—high (0.15–0.4 Hz) frequency components, LF/HF—low to high frequency ratio.