Modulating effect of respiration on atrioventricular conduction time assessed using PR interval variation

Area of Science:

• Cardiovascular Physiology
• Autonomic Nervous System Regulation

Background:

• Respiratory sinus arrhythmia (RSA), heart rate variability with breathing, is well-studied.
• The impact of respiration on atrioventricular conduction delay (PR interval) remains less explored.

Purpose of the Study:

• To investigate and quantify the effect of respiration on atrioventricular conduction delay.
• To assess the reliability of different methods for measuring respiratory atrioventricular conduction delay variability (RCV).

Main Methods:

• Surface electrocardiogram (ECG) recorded RR and PR intervals in 11 subjects.
• Measurements were taken during paced and spontaneous respiration in a supine position.
• A wavelet-based approach was used for interval extraction; spectral, peak-to-trough, and cosinor methods assessed RCV.

Main Results:

• Statistically significant PR interval variations due to respiration were observed during paced breathing (6 min⁻¹).
• Cosinor analysis proved most reliable, detecting significant RCV in 10/11 subjects during paced respiration (mean variability ±5.9%).
• Significant RCV was found in about half of subjects during spontaneous respiration (mean variability ±1.5%).

Conclusions:

• Respiration modulates atrioventricular conduction delay, with deep breathing accentuating the effect.
• Cosinor analysis is a reliable method for quantifying respiratory atrioventricular conduction delay variability (RCV).
• This finding adds to the understanding of cardiorespiratory interactions.