# Lower loop re‐entrant flutter

## TL;DR

A patient with a history of heart attack had a rare type of heart rhythm disorder involving a specific electrical pathway in the right atrium.

## Contribution

The study presents a novel case of lower loop re-entrant flutter associated with prior atrial infarction.

## Key findings

- Electroanatomic mapping showed diffuse scarring in the right atrium from prior infarction.
- Activation wavefront was forced through an area of slow conduction, causing counterclockwise reentry.
- ECG findings correlated with septal activation in a cranio-caudal direction.

## Abstract

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.