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Figure 1 Kaplan-Meier survival curves (considering death from all causes as end point) in patients with revised cardiac risk index IV or less (A), in patients with low-frequency power of heart rate variability (HRV)/high frequency power of HRV (LF/HF ratio) before induction of anesthesia lower or higher than 2 (B), and in patients with or without elevation of cardiac troponin I on postoperative day 1 or 2 (C). (D) shows Kaplan-Meier survival curves of patients having none or only one of these three risk indicators or of patients having two or all three of them. HF = high frequency power; LF = low frequency power.