Background: Low heart rates (HRs) are preferable for coronary CT angiography (CTA). We evaluated the use of an intravenous bolus of ivabradine, a selective sinus node inhibitor, to lower HR before coronary CTA in a prospective, randomized, double-blind, placebo-controlled multicenter trial. Methods: A total of 370 patients scheduled for CTA, with sinus rhythm ≥70 beats/min but ineligible for intravenous beta-blockers, were randomized to an intravenous bolus of 10 mg (HR, 70-79 beats/min) or 15 mg (HR ≥80 beats/min) ivabradine or placebo. Primary end point was the proportion of patients achieving HR ≤65 beats/min at the initiation of coronary CTA (Ta). Results: Baseline HR was 79 ± 8.5 beats/min. At Ta, HR ≤65 beats/min was achieved in 55% of the ivabradine group vs 23% for placebo (. P < .0001) and in 68% vs 16% 1-hour after bolus administration (. P < .0001). Contrast-enhanced coronary CTA was performed in 87% of the ivabradine group vs 65% for placebo (. P < .0001). Mean HR at Ta was 67 ± 10 beats/min for ivabradine vs 75 ± 10 beats/min for placebo (. P < .0001). Procedural convenience was scored better with ivabradine ("good" or "very good" in 79% vs 63% for placebo; P = .0005). The effective radiation dose of contrast-enhanced CTA was 13 ± 7 mSv for ivabradine vs 16 ± 7 mSv for placebo (. P < .05). Ivabradine was well tolerated. Conclusions: An intravenous bolus of ivabradine achieves rapid, safe, and sustained HR lowering during coronary CTA, increasing procedural convenience and reducing radiation exposure vs placebo.

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Journal of Cardiovascular Computed Tomography
Department of Radiology

Cademartiri, F, Garot, J, Tendera, M, & Zamorano, J.L. (2015). Intravenous ivabradine for control of heart rate during coronary CT angiography: A randomized, double-blind, placebo-controlled trial. Journal of Cardiovascular Computed Tomography, 9(4), 286–294. doi:10.1016/j.jcct.2015.04.005