Excerpt

Catheter ablation is difficult for parahisian accessory pathways (AP). Radiofrequency (RF) ablation from the non-coronary sinus of Valsalva or from the left ventricular outflow tract (LVOT) has been described in isolated cases [1, 2]. We present 3 consecutive patients with WPW syndrome and parahisian AP, safely ablated (no AV block) from the sinuses of Valsalva. Baseline electrocardiograms pre-ablation are shown with LBBB like pattern, inferior axis, and precordial transition at V3, at arrival to the EP lab (Fig. 1a). Case 1: male patient, 38-year-old, with history of palpitations and WPW known for several years. A first ablation approach with cryoablation (after mapping the accessory pathway to the superoparaseptal zone, in close proximity to the His location) was not effective, and the LVOT was targeted in a subsequent procedure. RF application at the junction between the right and the non-coronary sinuses (irrigated ablation catheter using image integration with CT) was effective (Fig. 1b and Fig. 2a). Case 2: male patient, 31-year-old, WPW pattern discovered in a routine exam. A stress test showed persistence of preexcitation at maximum effort (190 bpm). After mapping, the accessory pathway to a parahisian location, a first ablation approach with cryomapping temporary interrupted the AP, but transient PR prolongation occurred (Fig. 2b). In a second procedure, RF application at the non-coronary sinus was effective (Fig. 2b). Case 3: male patient, 31-year-old, admitted to cardiology after a syncopal event following palpitations. The ECG showed preexcitation and the accessory pathway was mapped to the parahisian region. Circus movement tachycardia and AF were induced. Initial RF in a region close to the His region (right approach) was not effective. RF application at the non-coronary sinus with a local electrogram showing an AP potential “P” (− 46 ms pre delta, Fig. 2c) was effective in 3.8 s (big A and small V with fusion in every patient at the successful ablation site, Fig. 2). Post procedure echocardiography in all three cases showed no complications. No recurrences were documented with a follow-up of 8–26 months.

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