METHODS
The single-center CHAOS study prospectively included all patients
scheduled for reentrant AT ablation from May 2017 to December 2019,
excluding patients diagnosed with CTI-dependent atrial flutter, in which
the tachycardia circuit was deemed non-mappable due to continuous
circuit modification or conversion to atrial fibrillation. All patients
had pre-procedural documentation of reentrant AT on the surface ECG
based on: 1) the presence of continuous atrial activity on the surface
ECG, or: 2) in patients with focal AT pattern, the arrhythmia behavior
(stable cycle length without modification at onset or end) and patient
characteristics (diseased atria).13 Patients could
present to the ablation procedure in sinus rhythm, AT or AF.
Written informed consent was obtained before the procedures and patient
data were collected in a dedicated database. The study complied with the
Declaration of Helsinki and received prior approval by the ethics
committee of our institution.