Radiofrequency ablation of left atrial appendage accessory pathway.

A 47-year-old man was referred to our hospital due to recurrent episodes of narrow QRS complex tachycardia. Baseline electrocardiogram showed ventricular pre-excitation in favour of left-sided accessory pathway (AP), so we decided to perform radiofrequency (RF) mapping and ablation of AP. During the ventricular pacing and orthodromic atrioventricular reciprocating tachycardia, the earliest atrial signal was in the distal coronary sinus, but even at that area the ventricular and atrial signals were not fused together. High-power RF via transseptal and then retrograde approach failed to terminate the arrhythmia across the mitral annulus (even in the anterolateral of mitral valve ring), but RF application in the base of left atrial appendage (LAA) (Figure 1) terminated the arrhythmia and render the atrial activation sequence during ventricular pacing concentric. The first complete and accurate delineation of AP, which was ablated in the LAA tip, was done by Di Biase et al. in 2010. He presented four cases requiring ablation at the tip of the LAA after both endocardial and epicardial mapping and ablation failed. Mah et al. described three young patients who had unsuccessful endocardial ablations, despite aggressive efforts and just dissection of the LAA from adjacent ventricular myocardium in the operating room by the cardiac surgeon led to loss of pre-excitation and no further tachycardia. Long et al. reported five patients whose AP was ablated at the base of LAA using the electro-anatomical mapping system (CARTO) after the failure of endocardial ablation.