Both right and left cervical cordotomies depress sympathetic indexes derived from heart rate variability in humans

Unilateral percutaneous cervical cordotomy, performed in humans to relieve intractable cancer pain, elicits signs of ipsilateral sympathetic block. In patients undergoing right or left percutaneous cervical cordotomy (9 per g roup), changes in sympathovagal, balance were evaluated by spectral analysi s of heart rate to confirm the sympatholytic effect of this Surgical proced ure and to investigate the lateralization of sympathetic cardiac control. F or these purposes, heart rate variability was recorded 1 hour before cordot omy and 24 hours later. Cordotomy significantly depressed the low frequency peak (LF) of heart rate variability and increased the high frequency compo nent (HF), when measured as a percentage of total power. As a consequence, the LF/HF ratio decreased significantly (P=.001), particularly during stand ing. The effects of right or left cordotomies were not significantly differ ent. in conclusion, in humans unilateral percutaneous cervical cordotomy de presses some sympathetic indexes (LF/total power ratio and LF/HF ratio) der ived from heart rate variability, irrespective of side.