Clinical, Electrocardiographic, and Electrophysiological Characteristics of Patients with Focal Atrial Tachycardia (FAT)

Although smaller studies have shown that the P-wave morphology from different anatomic locations, a detailed algorithm which characterizes the likely location of a tachycardia associated with a P-wave of unknown origin is still lacking. The purpose of this study was: 1) to perform a detailed analysis of the P-wave morphology in Focal Atrial Tachycardia (FAT) and to produce an algorithm for identification of the anatomic site of origin, and 2) to evaluate the clinical and electrophysiological characteristics of FAT.

In this retrospective study 146 patients underwent radiofrequency catheter ablation for right and left FATs and their clinical, electrocardiographic, and electrophysiological characteristics were included.

One hundred forty-six patients with FAT were included in the study (56% of them were female, mean age: 46±15 years, age range: from 15 to 86 years). The distribution of Atrial Tachycardia (AT) was 78% in right atrial and 22% in left atrial region. The most common site for right-sided ATs was crista terminal is while pulmonary vein was the most common origin for the left ATs. A female predominance of 60% was seen in right-sided AT and a male predominance of 60% was among left-sided tachycardias (p=0.04). Lead V1 was the most useful lead to distinguish right tachycardias from the left one. Atrial electrogram-P wave interval at successful ablation site was significantly longer among left-sided ATs (45±7 vs. 41±7 ms, p=0.006).

This study shows a significant gender differences between right and left ATs. Leads V1 and I were the most useful leads to localize the FAT. Proposed P-wave algorithm could determine the likely origin of tachycardia in 95% of the patients.