A possibility to interchange heart rate-slowing therapy with ivabradine and atenolol in patients with stable angina pectoris
Aim. To evaluate the efficiency and safety of an interchange of atenolol and ivabradine in patients who had stable angina pectoris without myocardial infarction in the history and left ventricular (LV) systolic dysfunction. Subjects and methods. The trial enrolled 31 patients less than 70 years of age who had sinus rhythm, functional classes ll-l angina on exertion without clinical signs of LV systolic dysfunction. At the first stage, 15 patients were randomized to ivabradine with its dose titration during 2 weeks; the other 16 patients were to atenolol. At the second stage, 10 patients were switched from ivabradine used at Stage 1 to atenolol 100 mg/day, other 10 patients who were on atenolol were switched to ivabradine 15 mg/ day, and 11 patients received combination therapy with ivabradine + atenolol in half doses. All the patients underwent treadmill exercise testing and applanation tonometry. Results. Atenolol, unlike ivabradine, lowered brachial blood pressure and unchanged the central index of its increment, which was associated with LV systolic elongation. On the contrary, ivabradine decreased the central increment index and exerted no significant effect on the duration of LV systole. By comparatively lowering heart rate, ivabradine as well as atenolol reduced pulse wave propagation velocity. Conclusion. If ivabradine or atenolol is insufficiently effective or poorly tolerated, there may be an interchange of the drugs, as well as their combination in half doses without substantially affecting their therapeutic action in patients with stable angina pectoris without LV systolic dysfunction.