Mapping and rotor ablation
Among the 18 included patients, 14 (77.7%) presented to the ablation
procedure in sinus rhythm; in 12 patients, an AT was induced but was
considered not mappable due to conversion to AF (n = 10) or continuous
circuit modification (n = 2); in the other 2 patients, programmed atrial
stimulation directly induced AF. 3 Patients (16.7%) presented in AT; in
2 of them, conversion to AF during mapping occurred; in the other
patient, after successful ablation of the index AT, programmed atrial
stimulation induced AF. 1 Patient (5.6%) presented in AF.
Mapping was performed with PentaRay NAV catheter (Carto3) in 5 patients
(28%), with IntellaMap ORION (Rhythmia) in 11 patients (61%), and with
Advisor HD Grid (Ensite Precision) in 2 patients (11%). Contact
force-sensing catheters were used for ablation in 6 patients (33.3%).
In 9 patients (50%), rotor mapping and ablation was performed only in
the LA; in 1 patient, only in the RA; in the other 8 patients (44.4%),
both atria were mapped. Detailed rotor mapping and ablation approach is
showed in Figure 2.
Rotors, defined as sites with fractionated quasi-continuous signals on
1-2 adjacent bipoles of the mapping catheter, were found in 13 patients
(72%) (median 2 [1–3] rotors per patient) (Figure 3); all detected
rotors showed temporal permanence after mapping and were target of
ablation. Focal rotor ablation was effective in 12 of these patients
(92%); in the other patient, after unsuccessful rotor ablation, 2 sites
with STD and non-continuous fragmentation were detected and successfully
ablated to stabilize AF into reentrant AT. In 1 patient without
detectable rotors, spontaneous stabilization of AF into reentrant AT
happened during mapping, and AT ablation could be successfully
performed. In the other 4 patients without rotors, sites with STD and
non-continuous fragmentation were detected (2, 3, 4 and 6 sites in each
patient) (Figure 4); ablation of these sites resulted in arrhythmia
stabilization into AT in 3 patients (75%); the other patient received
electrical cardioversion. Figure 5 shows location of the detected rotors
and sites with STD and non-continuous fragmentation; globally 44% were
related with the pulmonary veins antra.