Long-term amiodarone therapy and the risk of complications after cardiac surgery: Results from the Canadian Amiodarone Myocardial Infarction Arrhythmia Trial (CAMIAT)

OBJECTIVE: This study was undertaken to determine the association between amiodarone therapy and risk of complications of cardiac surgery in patients in the randomized placebo-controlled, double-blind Canadian Amiodarone Myocardial Infarction Arrhythmia Trial. METHODS: Prospectively collected data regarding postoperative complications in 82 patients who underwent cardiac surgery during Canadian Amiodarone Myocardial Infarction Arrhythmia Trial participation were analyzed; 36 patients were randomly assigned to receive amiodarone and 46 were assigned to receive placebo. Of the patients randomly assigned to receive amiodarone, 24 patients continued amiodarone treatment to within 7 days of the operation (active amiodarone group) and 12 patients had the amiodarone discontinued at least 7 days before the operation (discontinued amiodarone group). RESULTS: The baseline characteristics of the three groups were similar. The risks of ventricular fibrillation, atrial fibrillation, and respiratory complications were similar. The risk of requiring an intra-aortic balloon pump was significantly increased by amiodarone (34.8% vs 16.7% vs 8.7% for active amiodarone, discontinued amiodarone, and placebo groups, respectively, P =.024). There was no significant difference in the use of temporary pacing. Neither the mean duration of stay in the intensive care unit nor the 7- and 30-days mortalities were affected by amiodarone. CONCLUSIONS: Patients receiving long-term amiodarone treatment after myocardial infarction had a higher rate of intra-aortic balloon use after cardiac surgery. There was no increased risk of pulmonary complications, need for pacing, or death.