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Heart Rate Variability and Heart Failure with Reduced Ejection Fraction: A Systematic Review of Literature
Michiaki Nagai1,2, Hallum Ewbank3, Yukiko Nakano4
1Cardiovascular Section, Department of Medicine, University of Oklahoma Health Science Center, Oklahoma, OK 73104, USA.
Introduction:
Autonomic impairment is a hallmark of heart failure with reduced ejection fraction (HFrEF). While there have been studies on general values for each index of heart rate variability (HRV) analysis in HFrEF, a systematic review comprehensively examining representative values in HFrEF is lacking.
Methods:
We searched PubMed, Embase, and Cochrane databases to extract studies reporting representative values of HRV metrics in HFrEF.
Results:
A total of 470 HFrEF patients from 6 studies were included in the review. In general, time and frequency domains were abnormally lower in HFrEF, portending a worse prognosis. In HFrEF, the mean or median value of the standard deviation of NN interval, root mean square successive difference, pNN50, and low-frequency power/high-frequency power were 40 to 121 msec, 19 to 62 msec, 1.3 to 14%, and 1.00 to 1.73, respectively.
Conclusion:
In this systematic review, most HRV metrics were found to be calculated from 24- hour Holter recordings and were lower in HFrEF patients with poor prognosis.
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