In fact, many clinical and other types of studies of CCTA have reported the administration of β-blockers to lower heart rate for CCTA [3, 4]. One recent study reported high diagnostic capability with the assistance of the latest devices that shorten the imaging time and improve time resolution, without the use of β-blockers [5]. However, those results were obtained using only a specific model such as dual-source CT in an Fludarabine manufacturer updated facility,

and thus CT equipment commonly used in clinical practice still require the use of β-blockers to lower heart rate during CCTA. Furthermore, it is essential to lower the heart rate to reduce GDC-0994 cost exposure volume [6, 7] as many techniques to reduce the volume of exposure to radiation are applicable only at low heart rates. Injectable or oral β-blockers, which not only take more than 1 h to become effective but also have long half-lives [2.3 h for injection (propranolol), and 2.8 (metoprolol) to 3.9 h (propranolol) for tablets], thus constraining patients for a longer time, were widely used in previous studies. Therefore, Adriamycin chemical structure short-acting β-blockers have been demanded in order to achieve safer and more efficient inspection. The pharmacokinetic profile of landiolol hydrochloride shows high β1-selectivity as well as a very short half-life

(3.97 min) [8]. Landiolol hydrochloride has been a useful agent for improving the image quality of CCTA by 64- and 320-slice multi-detector CT (MDCT) as it was confirmed to reduce heart rate significantly and rapidly after intravenous injection [9–11]. Although

there are some studies in which the efficacy, safety, or usefulness of β-blockers has been explored [11, 12], no study has examined the usefulness and safety of short-acting β-blockers at an approved dosage and with approved administration in CCTA by 16-slice MDCT. Nowadays, 64-slice CT or newer CT equipment with more slices have the most advanced functions. However, due to the cost of 64-slice CT, most small- and medium-sized hospitals still have 16-slice CT. Sixteen-row CT is less expensive than the newer CTs and is still widely used in Japan. In ADAM7 addition, new low-dose algorithms for the reduction of radiation exposure are also available in CCTA with 16-slice CT, and the X-ray exposure dose of 16-slice MDCT is less than that of the 64-slice MDCT [13, 14]. It is possible to obtain an appropriate coronary image by 16-slice MDCT [15–22] if the patient’s heart rate during CCTA is properly controlled. In the present study, the usefulness and safety of the short-acting β1-receptor blocker landiolol hydrochloride (ONO-1101) 0.125 mg/kg for CCTA were assessed using 16-slice CT. 2 Methods 2.