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).