The most common thoracoscopic adaptation of box lesion procedure is currently recognized as Dallas lesion set performed with a set of non-irrigated ablation devices. In this procedure, a linear bipolar device is used to create ablation lines on the roof and the floor of the left atrium. Only pulmonary vein collectors are isolated with bipolar ablator clamp. For this reason, effectiveness of Dallas lesion set is lower than thoracoscopic adaptation of box lesion when all ablation lines are formed with ablator clamp (GALAXY procedure performed with irrigated ablator clamp).

MATERIAL AND METHODS

A technology of thoracoscopic box-lesion procedure using only one non-irrigated ablator clamp was developed. Twenty-one patients underwent this surgery. At the end of the blind period (90 days), all patients underwent endocardial mapping to study the quality of ablation lines.

RESULTS

There were no surgical complications. Throughout the blind period, 15 (71%) patients maintained stable sinus rhythm, and 6 ones had paroxysms of atrial fibrillation. All 21 patients underwent endocardial mapping at the end of the blind period (90 days). The quality (homogeneity and continuity) of ablation lines, completeness of isolation of pulmonary vein collectors and posterior wall of the left atrium were confirmed in all patients. In 6 patients with paroxysms of atrial fibrillation that persisted throughout blind period, extrapulmonary sources of ectopia outside the isolated zone were detected. We are thought that this was the cause of recurrent arrhythmia.

CONCLUSION

Original technique of radiofrequency ablation provides complete isolation of pulmonary vein collectors, roof, floor and posterior wall of the left atrium as evidenced by endocardial mapping. Preliminary positive clinical results suggest the follow-up for at least 24 months.