Respiratory muscle strength effect on linear and nonlinear heart rate variability parameters in COPD patients

• Published in: International journal of chronic obstructive pulmonary disease 2016-01, Vol.11 (1), p.1671-1677
• Main Authors: Goulart, Cássia Da Luz, Simon, Julio Cristiano, Schneiders, Paloma De Borba, San Martin, Elisabete Antunes, Cabiddu, Ramona, Borghi-Silva, Audrey, Trimer, Renata, da Silva, Andréa Lúcia Gonçalves
• Format: Article
• Language: English
• Subjects: Aged; Analysis; Arrhythmia; Autonomic Nervous System - physiopathology; Body mass index; Cardiac arrhythmia; Chronic obstructive lung disease; Chronic obstructive pulmonary disease; Exercise; Exhalation; Female; Heart - innervation; Heart Rate; Humans; Inhalation; Laws, regulations and rules; Linear Models; Lung - physiopathology; Lung diseases; Male; Manometry; Medical research; Middle Aged; Muscle Strength; Nonlinear Dynamics; Original Research; Patients; Predictive Value of Tests; Pulmonary Disease, Chronic Obstructive - diagnosis; Pulmonary Disease, Chronic Obstructive - physiopathology; Rehabilitation; Respiratory Muscles - physiopathology; Severity of Illness Index; Signal Processing, Computer-Assisted; Sinuses; Software; Spirometry; Standard deviation; Telemetry; Time Factors
• ISSN: 1178-2005; 1176-9106; 1178-2005
• DOI: 10.2147/COPD.S108860

Chronic obstructive pulmonary disease (COPD) is recognized as a multisystemic inflammatory disease associated with extrapulmonary comorbidities, including respiratory muscle weakness and cardiovascular and cardiac autonomic regulation disorders. We investigated whether alterations in respiratory muscle strength (RMS) would affect cardiac autonomic modulation in COPD patients. This study was a cross-sectional study done in ten COPD patients affected by moderate to very severe disease. The heart rate variability (HRV) signal was recorded using a Polar cardiofrequencimeter at rest in the sitting position (10 minutes) and during a respiratory sinus arrhythmia maneuver (RSA-M; 4 minutes). Linear analysis in the time and frequency domains and nonlinear analysis were performed on the recorded signals. RMS was assessed using a digital manometer, which provided the maximum inspiratory pressure (PImax) and the maximum expiratory pressure (PEmax). During the RSA-M, patients presented an HRV power increase in the low-frequency band (LFnu) (46.9±23.7 vs 75.8±27.2; P=0.01) and a decrease in the high-frequency band (HFnu) (52.8±23.5 vs 24.0±27.0; P=0.01) when compared to the resting condition. Significant associations were found between RMS and HRV spectral indices: PImax and LFnu (r=-0.74; P=0.01); PImax and HFnu (r=0.74; P=0.01); PEmax and LFnu (r=-0.66; P=0.01); PEmax and HFnu (r=0.66; P=0.03); between PEmax and sample entropy (r=0.83; P