Department of Cardiology, Sanjay Grandhi Post Graduate Institute of Medical Sciences, Lucknow, India.
Br J Radiol. 2012 Aug;85(1016):e424-8. doi: 10.1259/bjr/22102914.
To investigate the role of oral ivabradine as a heart rate reducing agent in patients undergoing CT coronary angiography (CTCA). Despite the routine use of β-blockers prior to CTCA studies, it is not uncommon to have patients with heart rates persistently above the target range of 65 bpm. Ivabradine is a selective inhibitor of the I(f) current, which primarily contributes to sinus node pacemaker activity, and has no significant direct cardiovascular effects such as reduction of blood pressure, cardiac contractility or impairment of cardiac conduction.
We investigated 100 consecutive patients who had been referred for CTCA for the evaluation of suspected coronary artery disease (CAD). Patients were randomised to receive either of the following two pre-medication protocols: oral metorprolol or oral ivabradine.
Ivabradine was significantly more effective than metorprolol in lowering the heart rate; the mean percentage reduction in heart rate with ivabradine vs metorpolol was 23.89+6.95% vs 15.20+4.50%, respectively (p=0.0001). Metoprolol significantly lowered both systolic and diastolic blood pressure while ivabradine did not. The requirement of additional doses to achieve a target heart rate of <65 beats per min was also significantly more frequent with metoprolol.
Ivabradine is a potentially attractive alternative to currently used drugs for reduction of heart rate in patients undergoing CTCA.
研究伊伐布雷定作为一种心率降低剂在 CT 冠状动脉成像（CTCA）患者中的作用。尽管在 CTCA 研究前常规使用β受体阻滞剂，但仍有不少患者的心率持续高于 65 bpm 的目标范围。伊伐布雷定是 I(f)电流的选择性抑制剂，主要参与窦房结起搏活动，并且没有显著的直接心血管作用，如降低血压、心肌收缩力或损害心脏传导。
我们调查了 100 例连续因疑似冠心病（CAD）而行 CTCA 检查的患者。患者随机接受以下两种预用药方案之一：口服美托洛尔或口服伊伐布雷定。
伊伐布雷定比美托洛尔更有效地降低心率；伊伐布雷定与美托洛尔相比，心率降低的平均百分比分别为 23.89+6.95%和 15.20+4.50%（p=0.0001）。美托洛尔显著降低收缩压和舒张压，而伊伐布雷定则没有。为达到<65 次/分钟的目标心率而需要额外剂量的情况，美托洛尔也明显更为频繁。
伊伐布雷定是 CTCA 患者降低心率的一种有吸引力的替代药物，优于目前使用的药物。
