Procedural characteristics and outcomes
Patients’ baseline rhythm on the day of the procedure was AF in 22 cases (88%), whereas one patient had atrial tachycardia, and three patients were in sinus rhythm. In two of these latter, AF could be induced with burst stimulation. Of note, 12 patients (48%) had pulmonary vein reconnection at the time of endo-/epicardial CA.
During the stepwise procedure, sinus rhythm was restored in 18 patients (72%). We either observed direct conversion of AF to sinus rhythm during ablation in six patients (24%), or an initial organization into atrial tachycardias (n=33 atrial tachycardias), which were subsequently effectively mapped and ablated in 12 patients (48%). Six patients (24%) required electrical cardioversion at the end of the procedure, whereas in the remaining subject (4%) AF was non-inducible at baseline.
Direct conversions to sinus rhythm most commonly occurred during ablation of the BB (n=5), whereas one patient had sinus rhythm directly restored during ablation of complex/fractionated potentials in the RA, from the endocardium. Pulmonary veins were never implicated in arrhythmia termination.
Bidirectional conduction block across the linear lesion on the anterior wall of the LA was obtained in 16 patients (64%) after endocardial CA, whereas in the remaining nine patients (36%) epicardial lesions were needed.
Notably, at the end of the procedure, lack of arrhythmia inducibility was observed in 21 patients (84%). Two patients (8%) developed AF, which was electrically cardioverted, whereas five atrial tachycardias were induced, mapped and ablated in two subjects (8%), restoring sinus rhythm; however, AF inducibility persisted in these two latter patients.
Overall, during the course of the stepwise procedure, AF organized into a median number of one atrial tachycardia per patient (IQR, 3; total count, 38). Of these arrhythmias, nine (24%) were mapped and successfully ablated in the BB (figure 4), seven in the proximal portion of the LA appendage (18%), and five (13%) in the free wall of the RA; other locations were rarer (Table 2).