Prognostic Value of Heart Rate Variability in Patients with Cancer

Introduction: Previous studies have shown that autonomic dysfunction is associated with shorter survival in patients with advanced cancer. We examined the association between heart rate variability, a measure of autonomic function, and survival in a large cohort of patients with cancer. Methods: We retrospectively examined the records of 651 patients with cancer who had undergone ambulatory electrocardiogram monitoring for 20 to 24 hours. Time domain heart rate variability (SD of normal-to-normal beat interval [SDNN]) was calculated using power spectral analysis. Survival data were compared between patients with SDNN ≥ 70 milliseconds (Group 1, n 520) and SDNN < 70 milliseconds (Group 2, n 131). Results: Two groups were similar in most variables, except that patients in group 2 had a significantly higher percentage of male patients (P 0.03), hematological malignancies (P 0.04), and use of non-selective serotonin reuptake inhibitor antidepressants (P 0.04). Patients in group 2 had a significantly shorter survival rate (25% of patients in group 2 died by 18.7 weeks vs. 78.9 weeks in group 1 patients; P < 0.0001). Multivariate analysis showed that SDNN < 70 milliseconds remained significant for survival (hazard ratio 1.9 [95% confidence interval: 1.4-2.5]) independent of age, cancer stage, and performance status. Conclusion: The presence of cancer in combination with decreased heart rate variability (SDNN < 70 milliseconds) is associated with shorter survival time.