[Technical considerations for the epicardial approach in Wolff-Parkinson-White syndrome]

Epicardial approach consists of meticulous dissection of the annular fat pad of the Kent bundle site and subsequent cryocoagulation from the epicardial side. This technique obviates the need of atriotomy and makes ablation without cardiopulmonary bypass possible. In performing this approach for patients with the left parietal or posteroseptal pathway through median sternotomy, special technical strategies are necessary to keep hemodynamic status stable during dissection and cryoablation procedures, because in these cases apex of the heart has to be retracted upward to approach the Kent bundle site. For this purpose, the use of an ultrasonic surgical aspirator for dissection of the annular fat pad is required. With this instrument fat tissue is emulsified and aspirated by stroking the fat pad gently, easy dissection is possible without injury to major coronary vessels, even through a narrow operative field. Another point is to dissect the annulus fat below the coronary sinus (i.e., at the space between the coronary sinus and circumflex coronary artery), not above it. By doing this extensive retraction of the apex is no longer necessary. In performing cryocoagulation care has to be taken not to involve the coronary artery into the lesion. However, too tight retraction of the coronary artery may cause another risk of thrombosis. Sometimes moderate systemic heparinization should be performed during coronary retraction and cryocoagulation procedure.