Position-dependent changes in vagal modulation after coronary artery bypass grafting

Reduced cardiac vagal modulation increases propensity to arrhythmias. Right decubitus position is a vagal enhancer in coronary and congestive heart disease. We evaluated vagal modulation before and after coronary artery bypass grafting (CABG) in 30 patients. Heart rate variability (HRV) indexes in frequency domain were calculated from 10-min digital electrocardiograms. Kolmogorov–Smirnov and paired tt-tests were applied, p<0.05p<0.05 was considered significant. The HRV indexes decreased after CABG. Higher LF/HF ratio and shorter mean RR were observed in right recumbent position postoperatively. Right lateral decubitus position did not give rise to higher vagal modulation after heart surgery.