LAUSR

Patients with COPD show impairments in several autonomic function (AF) parameters such as heart rate variability (HRV) and baroreceptor reflex sensitivity (BRS). This study assessed AF using a standardized battery of test among subjects with COPD during a pulmonary rehabilitation (PR) program. A total of 25 severe COPD (age: 66±9 years; BMI: 26.3±3.48m/kg2) and 11 healthy age-matched control subjects (age: 64±9.6 years; BMI: 25±2.27 m/kg2) participated in this study. A continuous ECG monitoring was conducted during four test moments in supine position; rest (15 minutes), deep breathing (6 cycles/minute), valsalva maneuver and tilting to 60 degrees. Linear parameters in time (standard deviation of NN intervals [SDNN] and the root mean square of successive differences [RMSSD]) and frequency domains (high frequency [HF] and low frequency [LF] bands) analyses, and non-linear (standard deviations [SD] 1 & 2) parameters of HRV and BRS values were analyzed and retrieved. Alpha probability value was significant at 0.05. The results indicated that the subjects (COPD & controls) showed comparable HRV values at rest, following deep breathing and during valsalva maneuver recovery phase (p>0.05). However, subjects with COPD showed significantly lower values in most HRV parameters (SDNN, RMSSD, LF, LF/HF ratio, LF (normalized), HF(normalized), SD1 & SD2) following tilting compared to control group subjects (p 0.05). These results suggest that residual autonomic nervous system deficits persist in subjects with COPD undertaking PR. This should be taken into account in subsequent therapeutic approach to AF modulation in severe COPD.