Endocardial ablation
All patients underwent an endocardial catheter ablation as second step
procedure, after a median time from surgery of 34 [IQR] days. At the
time of endocardial ablation, 26 (43%) patients were in sinus rhythm,
27 (45%) in AF and 7 (12%) patients in atypical atrial flutter. No
significant differences in rhythm type at endocardial ablation
presentation were observed between the two groups.
At the beginning of the endocardial procedure, complete isolation of the
posterior LA wall was observed in 22 (36%) patients (n = 10 in BB
group, n = 12 in conventional group (P=NS)). Achievement of electrical
box isolation required endocardial ablation of the septal aspect of the
box in 14/38 patients (36%); of the roof of the box in 12/38 patients
(31%); of the lateral aspect of the box in 23/38 patients (60%); of
the inferior aspect of the box in 32/38 patients (84%). After the box
lesion spontaneous restoration of the sinus rhythm occurred in 2
patients of the Bachmann’s group.
A bidirectional conduction block across the mitral isthmus line was
achieved in all patients in the Bachmann’s group compared with 21
patients (70%) in the conventional group (P=0.039). All patients
received ablation of the ligament of Marshall, coronary sinus septal
inter-caval, cavo-tricuspidal isthmus and superior vena cava isolation.
Finally, 3 patients in Bachmann’s group and 2 patients in conventional
group received additional ablations for focal atrial arrhythmias.
Total duration of the endocardial ablation was (126±42 min) in BB group
vs 143 (±39min) in the CONV group (p = NS). Average hospital stay
resulted 2.6 days in BB group vs 2.5 days for the CONV group (p = NS).
During endocardial ablation, a spontaneous restoration of sinus rhythm
was observed in all patients (n=16) in the BB group versus 5 patients
(28%) in the CONV group (p<0.001). Patients in the CONV group
still presenting AF (n=9) or atrial flutter (n=4) were successfully
converted to sinus rhythm by electrical cardioversion.
After completion of endocardial ablation, incremental atrial pacing was
conducted to test arrhythmia inducibility. Sustained atrial arrhythmias
(lasting >30 seconds) were observed in 1/30 patients in the
Bachmann’s group (3.6%), versus in 19/30 patients (64.4%) in the CONV
group (P= 0.0025). No major complications were recorded during the
endocardial procedures. Three patients showed modest groin hematoma that
non required intervention or transfusion.