Minimally invasive surgical pulmonary vein isolation alone for persistent atrial fibrillation: preliminary results of epicardial atrial electrogram analysis.

BACKGROUND

Minimally invasive surgical pulmonary vein isolation has become an alterative therapy for lone atrial fibrillation. This study evaluated the effect of the procedure on persistent atrial fibrillation by epicardial atrial electrography.

METHODS

Five consecutive patients with lone persistent atrial fibrillation were enrolled. Intraoperative electrophysiology tests were performed before and after minimally invasive surgical pulmonary vein isolation. Morphology of the recordings and atrial fibrillation cycle length were analyzed.

RESULTS

Sixty sites were recorded in 5 patients. Three types of bipolar electrogram were recorded at these sites. After ablation, all electrograms changed into type I in pulmonary veins and proximal antra, and remained unchanged in all proximal left atria. Atrial fibrillation cycle length at the proximal left atrium was shorter than that at the pulmonary veins. Atrial fibrillation cycle length recorded at proximal left atrium sites correlated with atrial diameter. The atrial fibrillation cycle length of the left atrium increased from 143 +/- 11 to 170 +/- 12 ms after pulmonary vein isolation. All 5 patients had atrial fibrillation immediately after the procedure and were treated with direct-current cardioversion and received amiodarone postoperatively. Freedom from atrial fibrillation was 100% at discharge and 60% at 6 months' follow-up.

CONCLUSIONS

Ectopic foci outside the pulmonary veins play an important role in persistent atrial fibrillation. Minimally invasive surgical pulmonary vein isolation might not be sufficient for persistent atrial fibrillation termination. The pulmonary vein isolation procedure, however, slows atrial fibrillation and makes supplemental pharmacologic cardioversion effective.