Is cardiac autonomic modulation during upper limb isometric contraction and Valsalva maneuver impaired in COPD patients?
OBJECTIVE
To evaluate the heart rate variability (HRV) indices and heart rate (HR) responses during isometric contraction (IC) and Valsalva maneuver (VM) in COPD patients.


METHODS
Twenty-two stable moderate to severe COPD patients were evaluated. R-R intervals were recorded (monitor Polar®S810i) during dominant upper limb IC (2 minutes). Stable signals were analyzed by Kubios HRV®software. Indices of HRV were computed in the time domain (mean HR; square root of the mean squared differences of successive RR intervals [RMSSD] and HRV triangular index [RR tri index]) and in the frequency domain (high frequency [HF]; low frequency [LF] and LF/HF ratio). The HR responses were evaluated at rest, at the peak and at the nadir of the VM (15 seconds). The Valsalva index was also calculated.


RESULTS
During IC: time domain indices (mean HR increased [P=0.001], RMSSD, and RR tri index decreased [P=0.005 andP=0.005, respectively]); frequency domain indices (LF increased [P=0.033] and HF decreased [P=0.002]); associations were found between forced expiratory volume in 1 second (FEV1) vs RMSSD (P=0.04;r=-0.55), FEV1vs HR (P=0.04;r=-0.48), forced vital capacity (FVC) vs RMSSD (P=0.05;r=-0.62), maximum inspiratory pressure (MIP) vs HF (P=0.02;r=0.68). FEV1and FVC justified 30% of mean HR. During VM: HR increased (P=0.01); the nadir showed normal bradycardic response; the Valsalva index was =0.7.


CONCLUSIONS
COPD patients responded properly to the upper limb IC and to the VM; however, HR recovery during VM was impaired in these patients. The severity of the disease and MIP were associated with increased parasympathetic modulation and higher chronotropic response.
Course of Physiotherapy, University of Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Cássia da Luz
CD
Goulart
Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of São Carlos, São Carlos, Brazil.
Ramona
R
Cabiddu
Course of Physiotherapy, University of Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Paloma de Borba
PB
Schneiders
Course of Physiotherapy, University of Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Elisabete
E
Antunes San Martin
Department of Physiotherapy, Federal University of Amazonas, Manaus, AM, Brazil.
Renata
R
Trimer
Cardiopulmonary Physiotherapy Laboratory, Nucleus of Research in Physical Exercise, Federal University of São Carlos, São Carlos, Brazil.
Audrey
A
Borghi-Silva
Course of Physiotherapy, Department of Health and Physical Education, University of Santa Cruz do Sul, Rio Grande do Sul, Brazil; Pulmonary Rehabilitation Program, Santa Cruz Hospital, Santa Cruz do Sul, Rio Grande do Sul, Brazil.
Andréa Lúcia Gonçalves
AL
da Silva
D000222:Adaptation, Physiological; D000368:Aged; D001341:Autonomic Nervous System / Q000503:physiopathology*; D001938:Brazil; D018592:Cross-Over Studies; D003430:Cross-Sectional Studies; D005260:Female; D005541:Forced Expiratory Volume; D006321:Heart / Q000294:innervation*; D006339:Heart Rate; D006801:Humans; D007537:Isometric Contraction; D008168:Lung / Q000503:physiopathology*; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000503:physiopathology*; D029424:Pulmonary Disease, Chronic Obstructive / Q000175:diagnosis / Q000503:physiopathology*; D020127:Recovery of Function; D013997:Time Factors; D034941:Upper Extremity; D014636:Valsalva Maneuver; D014797:Vital Capacity
COPD; Valsalva maneuver; autonomic nervous system; heart rate; isometric contraction