Submitted to: Biological Research for Nursing
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 4/1/2006
Publication Date: 4/1/2006
Citation: Burr, R.L., Motzer, S.A., Chen, W., Cowan, M.J., Shulman, R.J., Heitkemper, M.M. 2006. Heart rate variability and 24-hour minimum heart rate. Biological Research for Nursing. 7(4):256-267. Interpretive Summary: Heart rate variability based on 24-hour electrocardiograph recordings has been used in clinical research studies to assess the autonomic nervous system activity. The purpose of this study was to describe the relationships between 24-hour minimum heart rate and different analytical measures of heart rate variability. Normal women, normal men, children enrolled in a study of recurrent abdominal pain, irritable bowel syndrome women, sudden cardiac arrest survivors, and heart failure patients were studied. The 24-hour minimum heart rate correlated well with the common techniques that we use to measure heart rate variability. We conclude that 24-hour minimum heart rate might be useful as a simpler proxy, surrogate, or auxiliary variable in some clinical research applications.
Technical Abstract: Heart rate variability (HRV) indices based on 24-hour electrocardiograph recordings have been used in clinical research studies to assess the aggregate activity of the autonomic nervous system. While 24-hour HRV is generally considered non-invasive, use in research protocols typically involves considerable data collection and processing expenses, and substantial subject/participant burden. The purposes of this research methods evaluation were to describe the relationships between 24-hour minimum heart rate (HR) and several 24-hour time domain HRV indices (Ln SDNN, Ln SDANN, Ln SDNNIDX, Ln RMSSD, and Logit50) across several research data sets (normal women, normal men, children enrolled in a study of recurrent abdominal pain, irritable bowel syndrome women, sudden cardiac arrest survivors, and heart failure patients), and to explore the possibility that 24-hour minimum HR might serve as a simpler alternative or adjunct to HRV measures in some situations. Results: The correlations of 24-hour minimum HR with global HRV measures (e.g., Ln SDNN, Ln SDANN) were consistently very strong (typical r ~ -0.80), and always stronger than average HR (typical r ~ -0.50). In repeated measurements, change in minimum HR was also well-correlated with change in general HRV (typical r ~ -0.60). However, modest differentiation of minimum HR and HRV measures was noted in subjects taking certain classes of cardiac medications (e.g., anti-arrhythmics, beta blockers). Conclusion: 24-hour minimum HR has a remarkably strong correlation with general time domain HRV measures, and might be useful as a simpler proxy, surrogate, or auxiliary variable in some clinical research applications, especially those whose participants were not receiving cardiac medications.