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[摘要]：Several studies have demonstrated the correlation of heart rate (HR) and image quality in coronary computed tomography angiography. Beta-blocker administration is critical because of its negative inotropic effect. Ivabradine is a selective HR-lowering agent that exclusively inhibits the If current in sinoatrial node cells without having any effect on cardiac contractility or atrioventricular conduction. A total of 120 patients were randomized to oral premedication with ivabradine 15 mg or metoprolol 50 mg. HR and blood pressure (BP) were measured before the administration of premedication and immediately before coronary computed tomographic angiography. The mean time between premedication administration and follow-up was 108 +/- 21.5 minutes for ivabradine and 110 +/- 22.2 minutes for metoprolol (p = NS). When comparing groups, there were no significant differences in reduction of HR (-11.83 +/- 8.6 vs 13.20 +/- 7.8 beats/min, p = NS) and diastolic BP (-5.05 +/- 14.2 mm Hg vs 4.08 +/- 10.8 mm Hg, p = NS), whereas the decrease of systolic BP was significantly lower in patients who received ivabradine compared to those in the metoprolol group (-3.95 +/- 13.6 vs -13.65 +/- 17.3 mm Hg, p <0.001). In the subgroup of patients who were receiving long-term a-blocker therapy, significantly stronger HR reduction was achieved with ivabradine (-13.19 +/- 5.4 vs -10.04 +/- 6.0 beats/min, p <0.05), while the decrease in systolic BP was less (-2.00 +/- 13.6 vs -15.04 +/- 20.8 mm Hg, p <0.05) compared to metoprolol. In conclusion, ivabradine decreases HR before coronary computed tomographic angiography sufficiently, with significantly less depression of systolic BP compared to metoprolol. (C) 2012 Elsevier Inc. All rights reserved. (Am J Cardiol 2012;109:169-173) |
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