Tehran University of Medical Sciences The Research in Heart Yield and Translational Medicine (RHYTHM) 3115-7270 13 3 2018 07 15 136 139 EN Amer Harky Department of Cardiothoracic Surgery, Barts Heart Centre, St Bartholomew's Hospital, London, UK. AND Department of Vascular Surgery, Countess of Chester Hospital, Chester, UK. Mohamad Bashir Department of Cardiothoracic Surgery, Barts Heart Centre, St Bartholomew's Hospital, London, UK. Ciaran Grafton-Clarke School of Medicine, University of Liverpool, Cedar House, Liverpool, UK. Martin Lees School of Medicine, University of Liverpool, Cedar House, Liverpool, UK. Sarah Fendius Department of Cardiothoracic Surgery, Barts Heart Centre, St Bartholomew's Hospital, London, UK. Neil Roberts Department of Cardiothoracic Surgery, Barts Heart Centre, St Bartholomew's Hospital, London, UK. 2017 03 09 2018 05 10 Intraventricular conduction abnormalities following cardiac surgery have been thoroughly described, especially after valvular surgery. It is also widely known that several anesthetic factors can cause autonomic disturbances resulting in the unmasking of sinus node dysfunction, significant bradycardia, and cardiovascular collapse during the intraoperative period. However, little is known about asymptomatic episodes, especially those occurring prior to coronary artery bypass grafting (CABG). We report a rare occurrence of an intraventricular conduction defect that presented in an asymptomatic patient following non–ST-elevation myocardial infarction prior to urgent CABG. Our patient presented with sudden-onset chest pain, and following coronary angiography he was found to have triple-vessel coronary disease. During anesthetic induction for inpatient CABG surgery, he developed episodes of acute sinus tachy-brady episodes, requiring a stat dose of adrenaline to maintain the heart rate prior to the establishment of cardiopulmonary bypass. The arrhythmia persisted postoperatively, necessitating the insertion of a permanent dual-chamber pacemaker for complete heart block. The patient was later discharged without further complications, and upon follow-up 12 months later, he remains in good health. https://rhythm.tums.ac.ir/index.php/jthc/article/view/694 https://rhythm.tums.ac.ir/index.php/jthc/article/download/694/796