Abstract 16115: Switching From β-blockers to Ivabradine: Effects on Cardiopulmonary Function in Patients With Stable Coronary Artery Disease and Hypertension
Purpose: Ivabradine (Iva) is recommended for patients with stable coronary artery disease (CAD) who do not tolerate β-blockers. As Iva does not affect cardiac contractility or central hemodynamics, we speculated, that switching therapy from β-blockers to Iva may improve cardiopulmonary performance.
Methods: 19 patients (3 women, age 61 ± 10 years, LVEF 61 ± 5 %) with CAD were included. Chronic β-blocker therapy was going to be replaced by Iva due to side-effects of β-blockade. We performed cardiopulmonary exercise testing, pulmonary function testing and echocardiography and determined NT-proBNP serum levels both under β-blockade and 6 weeks after Iva therapy.
Results: Mean HR (68 ± 8 vs. 67 ± 10 bpm; p=0.508), systolic blood pressure (p=0.224), pulmonary vital capacity (p=0.726) and forced expiratory volume in 1 second (p=0.969) were not different under β-blocker or Iva at resting conditions. Left ventricular filling index (E/e’) was slightly lower under Iva (11.4 ± 4.8 vs. 9.2 ± 3.2; p=0.085). No patient showed signs of myocardial ischemia at rest or under exercise. Patients achieved the same level of exercise duration (p=0.620), maximal power (p=0.846), serum lactate levels (p=0.529) and heart rate increase (p=0.967) with or without β-blockade. Although peak oxygen uptake (21.9 ± 5.4 vs. 22.3 ± 4.4 ml/min/kg; p=0.470) did not change, oxygen uptake at the anaerobic threshold increased from 9.8 ± 1.5 to 11.5 ± 1.8 ml/min/kg (p=0.008) and peak oxygen pulse revealed a increase from 193 ± 41 to 210 ± 37 μl/beat/kg (p=0.010) after switching therapy to Iva. NT-proBNP serum levels were not different under β-blockade or Iva at rest (177 ± 179 vs. 162 ± 169 pg/ml; p=0.472), but the increase of serum levels during exercise tended to be lower under Iva (17 ± 45 vs. 7 ± 18 pg/ml; p=0.070).
Conclusions: Switching therapy from β-blockers to Iva in patients with CAD leads to a significant delay in the onset of anaerobic metabolism as demonstrated by higher oxygen uptake at the anaerobic threshold during exercise. Moreover, left ventricular fillings pressures and NT-proBNP serum levels tended to be lower under Iva therapy. The results of this pilot study suggest, that compared to β-blockade, therapy with Iva could make patients more resistant to fatigue in everyday life and activity.
- Exercise tests
- Beta-adrenergic receptor agonists
- Cardiorespiratory fitness
- Natriuretic peptide
- Physical activity
- © 2013 by American Heart Association, Inc.