Operative therapy of atrioventricular node reentry and results of an anatomically guided procedure.

Operative therapy for atrioventricular (AV) node reentrant tachycardia consisting of dissection guided by anatomic landmarks is described. Of the 21 patients studied, 17 had the common type ("slow-fast") and 4 had the uncommon type ("fast-slow") of AV node reentry. Under normothermic cardio-pulmonary bypass, perinodal dissection was performed guided by anatomic landmarks: the atrial membranous septum, posterior superior process of the left ventricle, tendon of Todaro and os of the coronary sinus. There were no deaths or major complications. Seven to 10 days postoperatively, all patients had normal AV conduction except for one who continued to have AV node Wenckebach-type block. Postoperatively, the shortest cycle length capable of 1:1 conduction over the AV node changed from 323 +/- 66 to 421 +/- 90 ms (p less than 0.0001) anterogradely and from 330 +/- 86 to 449 +/- 164 ms (p = 0.004) retrogradely. Anterograde effective refractory period of the AV node prolonged from 264 +/- 49 to 358 +/- 107 ms (p = 0.012). Discontinuous AV conduction curves were no longer seen in 14 of 17 patients and 5 patients lost retrograde conduction. During follow-up (14.8 +/- 8.2 months), 19 patients have been free of arrhythmia without medication. Two patients required a second operation for recurrent tachycardia with success. No patient required a permanent pacemaker. These data show that operative therapy of AV node reentrant tachycardia can be guided by anatomic landmarks. Successful cure of tachycardia with perinodal dissection while preserving AV node conduction supports the view that the reentrant circuit is, at least in part, perinodal.