Is amiodarone a safe antiarrhythmic to use in supraventricular tachyarrhythmias after lung cancer surgery?

Background: Supraventricular arrhythmias after thoracotomy for pulmonary resections are well documented. There has been considerable interest in their incidence, nature, predictability from preoperative assessment and treatment. The purpose of this study is to define prevalence, type, risk factors for post-thoracotomy supraventricular arrhythmias and to assess the efficacy of amiodarone as an antiarrhythmic drug.

Methods: The records of 250 patients undergoing pulmonary resection for lung cancer during last two years were followed up in this prospective study with particular attention to possible risk factors (gender, age, extent and side of resection, diabetes mellitus, hypertension, tobacco smoking, beta-blocker ingestion). Patients underwent biopsy only were excluded. Once onset of supraventricular arrhythmia was monitored or documented in the electrocardiogram, intravenous infusion of amiodarone was started with a loading dose of 5 mg/kg in 30 minutes and a maintenance dose of 15 mg/kg until remission of it.

Results: Forty-three episodes (21.6%) of supraventricular arrhythmias were documented with atrial fibrillation being the most common (88.3%). Rhythm disturbances were most likely to develop on the second postoperative day. Pneumonectomy, lobectomy and age >65 years were the statistically significant factors. The overall postoperative mortality was 3.2% and 2.3% for the patients with postoperative supraventricular arrhythmias. In none of the cases did supraventricular arrhythmia cause cardiac failure leading to death. Sinus rhythm was achieved with amiodarone in 37 out of 43 patients (86%). Electrical cardioversion was necessary for 6 patients who were hemodynamically unstable. The most common amiodarone-related complication was bradycardia (13.5%).

Conclusions: Postoperative supraventricular arrhythmias are a common complication in elderly patients undergoing lung resection surgery (especially pneumonectomy or lobectomy). Amiodarone is both safe and effective in establishing sinus rhythm.