RESUMO
BACKGROUND: In patients with contraindication for beta-blockers who are also under long-term calcium channel-blocker therapy for any reason, ivabradine may be used as an alternative treatment to achieve the target heart rate. PURPOSE: To assess whether single dose oral ivabradine in patients referred for coronary computed tomography angiography (CCTA) is safe and can significantly decrease heart rate compared to intravenous (i.v.) metoprolol in patients receiving long-term calcium channel-blocker therapy. MATERIAL AND METHODS: One-hundred and twenty patients who were under calcium channel-blocker therapy referred for CCTA were randomized to premedication with single dose (15 mg) ivabradine (n = 63) or i.v. metoprolol (5-10 mg) (n = 62). Hearth rate (HR) was assessed at admission (HR1), prescan (HR2), and during CCTA scan (HR3) for all patients. Blood pressure (BP) was measured before medication (BP1) and immediately before CCTA scan (BP2). RESULTS: Although the HR averages of two groups were not significantly different before medication (HRIv1 = 80 ± 7 bpm vs. HRß1 = 81 ± 7 bpm; P = 0.42), significant HR reduction was observed in the ivabradine group (HRIv3 = 62 ± 7 bpm) when compared to the metoprolol group (HRß3 = 66 ± 6 bpm; P = 0.001). Decreases in HR forivabradine (18 ± 6 bpm) was significantly higher than for metoprolol (15 ± 4 bpm; P = 0.003) without relevant side-effects. Ivabradine showed no significant effect on either systolic BP or diastolic BP (siBPIv1, 139 ± 10; siBPIv2, 138 ± 10; P = 0.260; diBPIv1, 81 ± 7; diBPIv2, 81 ± 6; P = 0.59). Nevertheless, metoprolol group demonstrated significant reduction in both SiBP and DiBP (siBPß1, 136 ± 11; siBPß2 130 ± 11; P < 0.001; diBPß1, 81 ± 6; diBPß2, 78 ± 6; P < 0.001). CONCLUSION: Single dose ivabradine is safe and significantly more effective than i.v. metoprolol in decreasing HR in patients under calcium channel-blocker therapy.
