Noninvasive ventilation can modulate heart rate variability during high-intensity exercise in COPD-CHF patients

Area of Science:

• Cardiorespiratory Physiology
• Autonomic Nervous System Function
• Clinical Exercise Physiology

Background:

• Chronic Obstructive Pulmonary Disease (COPD) and Chronic Heart Failure (CHF) often coexist, significantly impacting patients' exercise capacity and quality of life.
• Autonomic dysfunction, reflected in Heart Rate Variability (HRV), is common in these patient populations.
• The effects of Non-invasive Ventilation (NIV) on autonomic responses during high-intensity exercise in combined COPD-CHF are not well understood.

Purpose of the Study:

• To investigate the acute effects of NIV during high-intensity exercise on HRV in patients with both COPD and CHF.
• To compare HRV responses during exercise with NIV versus sham ventilation.
• To explore the relationship between COPD severity and HRV responses during NIV exercise.

Main Methods:

• A randomized, double-blind, controlled study involving 14 COPD-CHF patients.
• Patients underwent cardiopulmonary exercise testing (CPET) followed by two constant-load exercise tests (80% CPET peak load) with either NIV or sham ventilation.
• Continuous R-R interval recording during rest, exercise, and recovery, with subsequent HRV analysis (time, frequency, and nonlinear domains).

Main Results:

• NIV during exercise significantly altered autonomic markers, increasing mean heart rate (HR) and low-frequency (LF) power, while decreasing mean R-R intervals (iRR), root mean square of successive differences (rMSSD), and high-frequency (HF) power compared to rest.
• Compared to sham ventilation, NIV exercise resulted in lower rMSSD and Sample Entropy, indicating altered autonomic regulation.
• A negative correlation was observed between Forced Expiratory Volume in 1 second (FEV1) and HF power (nu) during NIV exercise, suggesting COPD severity impacts vagal response.

Conclusions:

• Non-invasive ventilation during high-intensity exercise significantly modifies heart rate and autonomic responses in patients with comorbid COPD and CHF.
• The severity of COPD is inversely associated with the vagal response during exercise when NIV is applied.
• These findings highlight the complex interplay between respiratory and cardiac conditions and autonomic control during exertion with ventilatory support.