Mapping and ablation of left atrial flutters

Background-Typical right atrial isthmus-dependent flutters have been described in detail, but very little is known about left atrial (LA) flutters. Methods and Results-We performed conventional and 3D mapping of the LA for 22 patients with atypical flutters. Complete maps in 17 patients demonstrated macroreentrant circuits (n=15) with 1 to 3 loops rotating around the mitral annulus, the pulmonary veins, and a zone of block or a silent area. In 2 patients, a small reentry circuit with a zone of markedly slow conduction was identified. Linear ablation performed across the most accessible part of the circuit cured 16 patients (73%) with a follow-up of 15+/-7 months. Conclusions-LA reentrant tachycardias are related to individually varying circuits and are amenable to mapping guided radiofrequency ablation.