Performance of heart rate adjusted heart rate variability for risk stratification of sudden cardiac death

Area of Science:

• Cardiology
• Autonomic Nervous System Function
• Biomedical Signal Processing

Background:

• Heart rate variability (HRV) is a non-invasive measure for assessing cardiovascular autonomic function.
• The predictive capability of traditional HRV metrics for sudden cardiac death (SCD) risk stratification remains uncertain.
• Existing HRV metrics may be influenced by heart rate (HR) variations, potentially affecting their accuracy.

Purpose of the Study:

• To evaluate the performance of individualized heart rate (HR) adjusted HRV (HRV_I) for SCD risk stratification.
• To compare the efficacy of HRV_I against traditional long-term and short-term HRV metrics.
• To investigate HRV_I in subjects across a spectrum of SCD risks.

Main Methods:

• Analyzed 11 HRV metrics in 192 subjects: healthy controls, hypertrophic cardiomyopathy patients, and SCD victims.
• Examined the relationship between HRV metrics and HR using long-term and short-term analyses.
• Assessed HRV_I performance using area under the receiver operating characteristic curve (AUC) and covariance of variation (CV).

Main Results:

• Most HRV metrics showed an exponential decay with increasing HR, with significant differences in decay rates among risk groups.
• HRV_I demonstrated superior discrimination of low, medium, and high SCD risk subjects (median AUC 0.72) compared to traditional HRV (AUC 0.63-0.58).
• HRV_I exhibited a significantly lower average CV (0.09 ± 0.02) than traditional short-term HRV (0.24 ± 0.13), indicating greater robustness.

Conclusions:

• A consistent exponential decay relationship between HRV metrics and HR exists across diverse SCD risk groups, differentiated by decay rates.
• HRV_I offers a reliable and robust method for SCD risk stratification.
• Individualized HR adjustment enhances the predictive value of HRV for cardiovascular autonomic function assessment.