Original ArticleDexmedetomidine Depresses Sinoatrial and Atrioventricular Nodal Function Without Any Change in Atrial Fibrillation InducibilitySairaku, Akinori MD; Nakano, Yukiko MD; Suenari, Kazuyoshi MD; Tokuyama, Takehito MD; Kawazoe, Hiroshi MD; Matsumura, Hiroya MD; Tomomori, Shunsuke MD; Amioka, Michitaka MD; Kihara, Yasuki MDAuthor Information Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, Hiroshima, Japan. Reprints: Akinori Sairaku, MD, Department of Cardiovascular Medicine, Hiroshima University Graduate School of Biomedical and Health Sciences, 1-2-3 Kasumi, Minami-ku, Hiroshima 734-8551, Japan (e-mail: [email protected]). The authors report no conflicts of interest. Journal of Cardiovascular Pharmacology: December 2016 - Volume 68 - Issue 6 - p 473-478 doi: 10.1097/FJC.0000000000000434 Buy Metrics Abstract It has been reported that dexmedetomidine (dex) has an impact on the cardiac conduction system and even has potential antiarrhythmic actions. We examined the influence of dex on the cardiac electrophysiological properties and atrial fibrillation (AF) inducibility. Adult paroxysmal AF patients were randomly assigned to receive (N = 107) or not receive (N = 108) dex during cardiac electrophysiological studies. The corrected sinus node recovery time (558 ± 331 vs. 459 ± 260 milliseconds; P = 0.02), Wenckebach cycle length (P < 0.001), atrioventricular nodal effective refractory period (317 ± 76 vs. 252 ± 54 milliseconds; P < 0.001), and atrio-His interval (P < 0.001) were longer in patients with dex than in those without. We tested the induction of repetitive atrial firing (RFA) defined as the occurrence of ≥2 successive atrial activities induced by single premature atrial stimuli to determine the AF inducibility. RFA was seen with a similar proportion (41.1% vs. 44.4%), yet it was evoked at a longer stimulus coupling interval in the dex patients, which was potentially attributed to the longer atrial effective refractory period (237 ± 36 vs. 213 ± 27 milliseconds; P < 0.001) and more prolonged atrial conduction delay seen in the dex group. In conclusion, dex may depress the sinus and atrioventricular nodal function, however, it may not reduce the AF inducibility. Copyright © 2016 Wolters Kluwer Health, Inc. All rights reserved.