Dose-Finding Study of Landiolol Hydrochloride: A Short-Acting β1-Blocker for Controlling Heart Rate During Coronary Computed-Tomography Angiography in Japan

INTRODUCTION Coronary computed-tomography angiography (CCTA) has high diagnostic performance, but it sometimes does not allow evaluation because of artifacts. Currently, the use of a β-blocker is recommended to prevent motion artifacts, but the β-blocker (metoprolol, propranolol, etc.) commonly used has a slow onset and long duration of action. Landiolol hydrochloride is an intravenous β1-blocker with a very short half-life. We investigated the efficacy and optimal dose of this drug for reduction of heart rate in patients undergoing CCTA. METHODS Eighty-seven subjects with ischemic heart disease were divided into three groups to receive landiolol hydrochloride at a dose of 0.125 (Group L), 0.25 (Group M), or 0.5 mg/kg (Group H). CCTA was performed at 3-7 min after administration, and heart rate, blood pressure, and image quality were assessed. RESULTS Heart rate decreased rapidly after completion of landiolol hydrochloride administration in all groups, with a heart rate reduction of 15.55 ± 6.56% in Group L, 16.48 ± 7.80% in Group M, and 21.49 ± 6.13% in Group H (Group L vs Group H, P = 0.0008; Group M vs Group H, P = 0.0109). Since there was no significant difference in heart rate during imaging among the three groups, although there was a significant difference between groups L and H and groups M and H in terms of percent change in heart rate, coronary stenosis was diagnosable in all groups with no significant difference. CONCLUSION Landiolol hydrochloride showed a rapid onset and short β-blocking effect, and was most effective at a dose of 0.5 mg/kg. However, the diagnosable proportion had no significant differences among the three groups in CCTA. Therefore, the clinically recommended dose was 0.125 mg/kg or less, considering the heart rate of patients with suspected coronary stenosis during CCTA.