Atypical Electrocardiographic Features of Cavotricuspid Isthmus-Dependent Atrial Flutter Occurring During Left Atrial Ablation for Atrial Fibrillation

Abstract

Background and Aim: Cavo-tricuspid isthmus (CTI)-dependent atrial flutter (AFL) can develop in patients who have undergone percutaneous catheter ablation for atrial fibrillation (AF) or during left atrial (LA) ablation for AF. The electrocardiographic (ECG) characteristics of CTI-dependent AFL during LA ablation have not been described in detail. The purpose of this study was to ascertain and describe the ECG features of CTI-dependent AFL occurring during percutaneous LA catheter ablation for AF. Methods and Results: Of 72 patients underwent AF ablation at our institution between January 2011 and December 2012, 33 (45.8%) exhibited CTI-dependent AFL during ablation for AF. Of these 33 patients, 26 and 7 exhibited typical and atypical ECG patterns, respectively. Flutter waves in the inferior leads were biphasic in 5 patients and positive in 2. Conclusions: CTI-dependent AFL during LA ablation for AF often exhibits atypical ECG characteristics. In patients in whom atrial flutter develops during LA ablation, entrainment mapping should be performed at the CTI even if the ECG is uncharacteristic of CTI-dependent AFL.