Exploring sleep heart rate variability: linear, nonlinear, and circadian rhythm perspectives

Area of Science:

• Veterinary Cardiology
• Physiology
• Biomedical Engineering

Background:

• Heart rate variability (HRV) shows potential for disease detection.
• Current HRV analysis in dogs often reflects advanced disease stages, limiting early detection.
• Developing novel HRV analysis methods is crucial for canine cardiovascular health.

Purpose of the Study:

• To compare 24-hour HRV with sleep-specific HRV in dogs.
• To evaluate the diagnostic utility of sleep HRV analysis for canine health.
• To investigate the influence of circadian rhythms on HRV parameters.

Main Methods:

• Cross-sectional study design.
• Analysis of 48-hour Holter recordings for both 24-hour and sleep HRV.
• Application of linear (time and frequency domain) and nonlinear HRV analysis techniques.
• Assessment of circadian rhythm parameters.

Main Results:

• Parasympathetic indices (nHF, SDNN, RMSSD, SD1, SD2) were significantly higher during sleep compared to the 24-hour average.
• Linear and nonlinear HRV analyses indicated increased parasympathetic activity during sleep.
• Circadian rhythm analysis revealed positive peaks for key parasympathetic indices during sleep.

Conclusions:

• Sleep HRV analysis provides a more precise reflection of canine parasympathetic activity.
• The findings support the use of sleep HRV for potentially earlier disease detection in dogs.
• Circadian rhythm integration enhances the interpretation of HRV data.