Episodic versus continuous prophylactic treatment with oral amiodarone for the prevention of permanent atrial fibrillation: a study on morbidity and quality of life
01 / 2001 - 12 / 2004
Background: Permanent atrial fibrillation (AF) causes complaints, heart failure and stroke. To lower morbidity, therapy is aimed at restoration and maintenance of sinus rhythm (SR). However, AF frequently relapses, predominantly during the 1st month after electrical cardioversion (ECV). Even when using a serial ECV approach only 40% of patients keep SR for 1 year. Amiodarone (amio) is the most effective prophylactic drug and may maintain SR in 70% of the patients for 2 years. However, its use is limited by adverse events, which are related to the daily dose and total duration of treatment (cumulative dose). Even with low dose amio (200 mg daily) yearly amio discontinuation rates amount 20-30%. Since elimination T1/2 of amio is 60 days, its efficacy persists after discontinuation. Avoiding amio induced adverse events may be accomplished by episodic amio treatment (EAT). Hypothesis: EAT peri-ECV (1 month before until 1 month after ECV, and repeated if AF relapses during follow-up) is associated with lower morbidity and higher quality of life compared to continuous amio treatment (CAT) while AF is still effectively suppressed. Objectives: 1. to show lower morbidity (i.e. adverse events related to amio use and AF itself) in patients randomized to EAT compared to those randomized to CAT; 2. to show higher quality of life in patients randomized to EAT compared to those randomized to CAT. Methods: 220 patients with persistent AF (> 24 hours) after a previous ECV will be randomized to (a) EAT or (b) CAT. After 4 weeks of amio loading (600 mg daily) ECV will be performed in both groups. In the EAT group amio (200 mg daily) will be discontinued 1 month post-ECV. In the CAT group amio will be administered daily during the total follow-up of 2 years. In the EAT group episodic peri-ECV amio treatment and ECV will be repeated if AF relapses. In the CAT group re-ECV will be performed if patients relapse > 3 months post-ECV, or if amio and desethylamio plasma levels at the moment of a relapse are too low. Expected results: during follow-up 18% of the patients in the EAT group versus 38% in the CAT group will discontinue amio due to adverse events while AF is suppressed in 70% of patients in both groups. Quality of life will be higher in the EAT group.