The effect of ivabradine on functional capacity in patients with chronic obstructive pulmonary disease.

Increased sympathetic tone and use of bronchodilators increase heart rate and this may worsen functional capacity in patients with chronic obstructive pulmonary disease (COPD). The aim of this study was to look at the short-term effect of the heart rate lowering drug ivabradine on clinical status in COPD patients. We randomised 80 COPD patients with sinus heart rate >= 90 bpm into either taking ivabradine 7.5 mg twice per day or placebo for two weeks. We assessed all patients using the modified Borg scale and 6-minute walk test at baseline and then again 2 weeks after randomisation. There were no significant differences in age, sex, severity of airway obstruction (measured using forceful exhalation), severity of diastolic dysfunction or pulmonary artery systolic pressure between the two groups. The ivabradine group showed significant improvement in 6-minute walk distance (from 192.6 +/- 108.8 mat baseline to 285.1 +/- 88.9 mat the end of the study) compared with the control group (230.6 +/- 68.4 at baseline and 250.4 +/- 65.8 m at the end of study) (p<0.001). This improvement in the drug group was associated with significant improvement of dyspnea on modified Borg scale (p=0.007). Lowering heart rate with ivabradine can improve exercise capacity and functional class in COPD patients with resting heart rate >90 bpm.