[Comparison of two electrode positions in electrical cardioversion of atrial fibrillation]

This study aims to compare effectiveness of electrical cardioversion (ECV) in patients with chronic atrial fibrillation (AF) according to the electrode positions: anteroapical (A-A) or anteroposterior (A-P). That which restores the sinus rhythm (SR) using the least energy is considered superior.

Observational study comparing two consecutive series of patients. SCOPE. Intensive Care Unit (ICU) of second level hospital.

Out-patients in AF referred to the ICU for biphasic ECV. The first series began with position A-A and the second one with A-P, administering up to 3 shocks (150-200-200J), changing to the alternative position if SR was not achieved and administering 2 more shocks of 200J. Age, gender, weight, baseline heart disease, ejection fraction, left atrial size, AF time, baseline vital signs, antiarrhythmic medication, reversion to SR, number of shocks, energy used and side effects were analyzed and compared between both series. RESULTS. A total of 50 patients were treated in each group. The baseline characteristics were similar except for a greater percentage of women in group A-A. The anteroapical electrode position achieved SR with significantly fewer numbers of shocks and less energy, more frequently achieving reversion on the first shock.

We found greater effectiveness in the electrical cardioversion of the AF with the electrodes in the anteroapical position, that we recommend as first choice. If it is not effective, the A-P position should be attempted.