Use of heart rate variability analysis to determine the risk of cardiac ischaemia in high-risk patients undergoing general anaesthesia.

The aim of this study was to investigate the use of pre-operative heart rate variability analysis to predict postoperative cardiac events (identified by 24 h Holter-ECG recording and an increase of creatine kinase MB) in high-risk cardiac patients. Length of hospital stay, the incidence of postoperative cardiac ischaemia and cardiac events after discharge were recorded. Fifty patients were assigned by the presence of cardiac events and the heart rate variability in 17 patients with an event was compared with 33 patients without. Total power was identified as a predictive parameter. The usefulness of this test was assessed in a second group of 50 patients. The incidence of cardiac events detected by Holter-ECG recording or an increased creatine kinase MB was greater and the duration of hospital stay longer in the 26 patients with total power < 400 ms(2).Hz(-1) compared with those with total power > 400 ms(2).Hz(-1) (eight and four patients and 10 (7) days (mean (SD)), vs 1 (p < 0.05) and 0 (p < 0.05) patients and 6 (2) days (p < 0.05), respectively). The total power of high-risk cardiac patients predicted postoperative cardiac events and extended length of hospital stay.