Severe Bradycardia Prior to Coronary Artery Bypass Graft Surgery: A Case Report.

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.