Heart rate variability in the elderly with chronic obstructive pulmonary disease submitted to acute application of bi-level positive airway pressure

Objective

To evaluate the acute effects of noninvasive ventilation, through bi-level positive airway pressure (BiPAP), on heart rate variability in elderly subjects with chronic obstructive pulmonary disease (COPD), and to compare the heart rate variability (HRV) in healthy elderly men with COPD patients.

Methods

Eighteen men (nine healthy men, aged 66 ± 4 years [control]; and nine men with COPD, aged 71 ± 7 years [G2]) were studied. The heart rate and R–R intervals (ms) were collected on a beat-to-beat basis from an electrocardiogram recording in the CM5 derivation with an electrocardiography monitor (Ecafix TC500). The signal was converted by an analogical/digital converser (Lab.PC+; National Instruments) and was processed by a specific routine. The record was collected in two conditions: 10 min at rest in the sitting position during spontaneous breathing, and 10 min during the same position with biBiPAP (BiPAP^® S; Respironics) application through a nasal mask. The BiPAP pressures slowly increased the inspiratory pressure up to 14–16 cmH₂O and expiratory pressure up to 6 cmH₂O, allowing voluntary adaptation. The BiPAP application was realized only in COPD. The heart rate and its variability were analyzed by the time domain (TD), through RMSSD (ms) and RMSM (ms) indexes, and the frequency domain (FD), which was expressed as normalized units of low frequency (LF), high frequency (HF) and the LF/HF ratio. The intragroup comparison was performed by the Wilcoxon test and the inter-group comparison by the Mann–Whitney test, with P < 0.05.

Results

See Table 1.

Table 1 Heart rate variability during the sitting position in spontaneous breathing with and without bi-level positive airway pressure (BiPAP) application between control and chronic obstructive pulmonary disease (COPD) patients

Conclusions

Our results suggest that the patients with COPD present modifications of sympathetic-vagal balance, with parasympathetic predominance over sympathetic in the sinoatrial node when compared with healthy elderly men. Moreover, the BiPAP application in this study reduced the HRV by DT analysis in COPD patients.