Conduction barriers in human atrial flutter: correlation of electrophysiology and anatomy

Animal models of atrial flutter and early mapping studies of human atrial flutter have suggested the importance of barriers in this reentrant arrhythmia. The consistency of rate and morphology of typical atrial flutter suggest a common anatomic substrate for this arrhythmia. The unique endocardial architecture of the right atrium provides anatomic barriers around which reentry occurs. In typical human atrial flutter, the crista terminalis, eustachian ridge, and tricuspid annulus have been identified as barriers to conduction. The importance of conduction barriers, methodology for defining barriers, the anatomic substrate for these barriers, and the role of these barriers in other atrial arrhythmias are discussed.