Brain-heart autonomic axis function across different clinical status and severity of COPD

Abstract

<b>Background:</b> Impairment of cardiac autonomic regulation integrity has been identified in chronic obstructive pulmonary disease (COPD). The interaction between clinical and severity status of the disease on the brain-heart autonomic axis (BHAA) is not well known. <b>Aim:</b> To investigate the BHAA function across different clinical status and severity of COPD. <b>Methods:</b> Cross-sectional study involving seventy-seven COPD patients allocated according clinical status [acute exacerbation - (GAE) or stable (GST)] and severity [less (-) or more (+)]: 1) GAE-, n=13; 2) GAE+, n=20; 3) GST-, n=23; and 4) GST+, n=21. Heart rate variability (HRV) at rest and heart rate recovery (HRR) after the six-minute walk test were markers of BHAA. Mean R-R, STDRR, RMSSD, RRtri, HF, LF, SD1 and SD2 were HRV indexes and, HRR = HR at 1st min of recovery - peak HR. <b>Results:</b> The main effect of clinical status (p&lt;0.001) was found to vagal indexes in GAE- vs. GST- (RMSSD: 25.0±14.8 vs. 12.6±5.5ms; SD1: 18.0±10.6 vs. 8.9±3.9ms) and to GAE+ vs. GST+ (RMSSD: 26.4±15.2 vs. 15.4±6.3ms; SD1: 18.3±11.2 vs. 10.9±4.5ms). A clinical status (p=0.032) and severity (p=0.030) effect were observed to HF in GAE+ compared to GAE- and GST+ (264.7±239.0 vs. 134.7±169.7 and 135.8±139.7ms2). Also, lower HRR was found to GAE- compared to GST- (8.0±2.4 vs. 19.6±2.4bpm)(p=0.002). <b>Conclusion:</b> In COPD patients, the clinical status (AECOPD or stable) was more dominant than severity on BHAA function. A more pronounced parasym­pathetic modulation was found in AECOPD patients with a lower HRR to exercise. <b>Financial support:</b> FAPESP 2015/26501-1 and CAPES Finance Code 001.