Heart rate variations in chronic obstructive pulmonary disease

Autonomic nervous system dysfunction proved in chronic obstructive pulmonary disease (COPD) patients might determine an elevated cardiovascular risk by heart rate alteration.

To assess the particularities of heart rate as a possible cardiovascular risk factor in COPD patients.

This prospective, case-control study comparatively analyzed the pulse rate continuously recorded with a polygraph in 32 COPD patients and 29 healthy subjects during rest (supine and sitting position) and during submaximal exercise (6-minute walk test). The relation between pulse rate and respiratory, functional or clinical alterations was analyzed in COPD patients.

The mean pulse rate was significantly higher during rest and exercise in COPD patients compared with the controls. However, the chronotropic response determined by exercise was similar in COPD and control groups: 55.19 beats/minute and 57.21 beats/minute, respectively (p=0.686). The mean pulse rate during exercise correlated with hypoxemia (r=-0.354, p=0.47) and with resting pulse rate (r=0.871, p<0.001 for supine position).

COPD associates elevated pulse rates during both rest and exercise. Hypoxemia and resting pulse rate are determinatives of chronotropic response during submaximal exercise in COPD patients.