Heart rate variability and cardiovascular diseases: A Mendelian randomization study.

Area of Science:

• Cardiology
• Genetics
• Epidemiology

Background:

• The link between heart rate variability (HRV) and cardiovascular diseases (CVD) remains unclear, with inconsistent findings in existing research.
• Mendelian randomization studies offer a method to investigate potential causal relationships using genetic variants.

Purpose of the Study:

• To explore the causal relationship between heart rate variability and cardiovascular diseases and associated events.
• To utilize Mendelian randomization to assess the genetic influence of HRV on CVD outcomes.

Main Methods:

• Selected instrumental variables for HRV: standard deviation of NN intervals (SDNN), root mean square of successive differences (RMSSD), and peak-valley respiratory sinus arrhythmia/high-frequency power (pvRSA/HF).
• Utilized publicly available genome-wide association study data for exposures and outcomes, including various CVDs and related events.
• Employed inverse variance weighted (IVW) for primary causal estimation, with MR-Egger, Cochran's Q test, and leave-one-out analyses to assess heterogeneity and pleiotropy.

Main Results:

• Genetically predicted pvRSA/HF showed a significant association with an increased risk of cardiac arrest (OR 2.02, 95% CI 1.25-3.28, p=0.004).
• The association remained robust, with no significant heterogeneity or pleiotropy detected.
• Leave-one-out analysis confirmed the reliability of the findings.

Conclusions:

• This Mendelian randomization study provides strong genetic evidence for a causal relationship between pvRSA/HF and cardiac arrest.
• The findings contribute to understanding the role of autonomic function, specifically parasympathetic activity reflected by pvRSA/HF, in cardiac arrest etiology.