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Use of non-contact mapping in the treatment of right atrial tachycardias in patients with and without congenital heart disease.

AIMS
Right atrial (RA) tachycardias may involve several mechanisms other than typical isthmus-dependent flutters, particularly in patients with congenital heart disease (CHD) or structural heart disease. We aimed at investigating the clinical utility of non-contact mapping in the diagnosis and ablation of these complex arrhythmias.


METHODS AND RESULTS
Non-contact mapping was used to treat RA tachycardias in 22 patients (12 with CHD and 10 without CHD). Ablation strategy consisted of creating linear lesions between scars (in macro-re-entrant circuits) or targeting areas of earliest activation and breakout points (in focal tachycardias). Eleven of the 12 tachycardias in the CHD group were atypical macro-re-entrant flutters. The majority (9 of 12) involved the RA free wall, whereas the remainder involved upper loop re-entry. In contrast, 9 of the 12 tachycardias in the non-CHD group were focal and 3 were macro-re-entrant. Acute procedural success was 88%. During a follow-up of 26 +/- 21 months, 90% of the patients reported either no symptoms (60%) or symptoms reduced to <50% pre-ablation levels (30%).


CONCLUSIONS
Non-contact mapping can provide important information on the mechanism of complex RA tachycardias in patients both with and without CHD. This can be useful in formulating ablation strategies.