Safety and efficacy of a rate control protocol for cardiac CT

The clinical application of cardiac CT is increasing, but heart rate control is often required to prevent motion artefact. Here, we describe a protocol for heart rate control in patients undergoing outpatient CT coronary angiography (CTCA). Among 121 consecutive patients, 75 (61.9%) with a resting heart rate >60 beats per minute (bpm) required rate control medication. Our protocol called for oral metoprolol 100 mg to be given 60 min before scanning, with patients for whom beta-blockers were contraindicated receiving 240 mg oral verapamil. Additional 5 mg intravenous boluses (maximum for both drugs, 15 mg) were given if the heart rate remained >60 bpm prior to scanning. Of 71 patients treated with oral metoprolol, 59 (83%) achieved a rate 70 bpm at the time of scanning. No adverse events resulted from rate control medication. Image quality was closely related to heart rate. Severe motion artefact (Grade 3) occurred in only 0.9% of patients with a rate 70 bpm. In conclusion, the administration of oral metoprolol according to the described protocol is a safe and effective way of reducing heart rate and improving scan quality in the majority of patients undergoing CTCA.