Lower loop re‐entrant flutter

An elderly man with a history of a prior inferior wall myocardial infarction underwent ablation for an atypical right atrial flutter. Electroanatomic mapping revealed diffuse scarring on the anterior, anterolateral, and posterior right atrium, presumably due to atrial infarction from the prior inferior wall myocardial infarction, forcing the activation wavefront through an area of slow conduction across the lower end of the crista terminalis, leading to lower loop reentry in a counterclockwise fashion around the inferior vena cava and a 12-lead ECG showing positive flutter waves in the inferior leads reflecting septal activation in a cranio-caudal direction.