Amiodarone for atrial fibrillation during off-pump coronary artery bypass graft surgery.

Case 1 An 81-year-old woman presented for OP-CAB surgery with severe 3-vessel coronary artery disease. Significant components of her past medical history included a diagnosis of mitral valve prolapse and 3 separate transient ischemic attacks that were believed to be related to the mitral valve dysfunction. Preoperative medications included metoprolol and enteric-coated acetylsalicylic acid. An intraoperative transesophageal echocardiogram revealed a left ventricular ejection fraction of 35% and moderate left atrial enlargement without evidence of thrombus. Shortly after opening the pericardium, the patient was noted to convert from sinus rhythm to atrial fibrillation. With this change in rhythm, the ventricular rate increased from 80 to 120 beats/min, and systolic blood pressure decreased from 125 to 90 mmHg. Synchronized electrical cardioversion was attempted 4 times without effect. A loading dose of 300 mg of amiodarone (patient’s weight, 49 kg) was administered intravenously over 30 minutes while the proximal vein graft anastomoses to the aorta were completed. During the amiodarone infusion, the patient’s ventricular rate slowed to 70 beats/min, and phenylephrine was administered for a mild transient decrease in blood pressure. After completion of the loading dose, the patient was electrically cardioverted to sinus rhythm on the first attempt. The patient then underwent 4 distal coronary artery anastomoses without further incident. An amiodarone infusion was initiated after the loading dose and continued for 24 hours. The patient’s recovery proceeded uneventfully, and no further arrhythmias had occurred at the time of discharge on postoperative day 7. Case 2 A 78-year-old man presented for OP-CAB surgery for treatment of 3-vessel coronary artery disease. The patient’s past medical history included non‐insulin-dependent diabetes, a remote stroke from which he had recovered, and cholelithiasis. Preoperative medications included glipizide, acetylsalicylic acid, atorvastatin, and amlodipine. A preoperative transthoracic echocardiogram was essentially normal with the exception of impaired left ventricular relaxation. The patient’s hospital course was remarkable for the development of acute cholecystitis requiring percutaneous cholecystostomy 7 days before OP-CAB surgery. At that time, the patient was noted to suffer a self-limited episode of atrial fibrillation lasting 1 hour. Atrial fibrillation recurred intraoperatively during inspection of the epicardial vessels. A loading dose of 450 mg of amiodarone (patient’s weight, 98 kg) was administered intravenously over 30 minutes without hemodynamic effect. After amiodarone loading, the patient was successfully electrically cardioverted to sinus rhythm. A 3-vessel OP-CAB procedure was completed, and the patient was transferred to the intensive care unit in stable condition. No further amiodarone was administered after the loading dose, and no further episodes of atrial fibrillation were noted during the patient’s hospital stay. An open cholecystectomy was performed on postoperative day 15, and the patient was discharged to a rehabilitation facility 21 days after his cardiac surgery. Case 3