Focal atrial tachycardia arising from the cavotricuspid isthmus with saw-tooth morphology on the surface ECG: electrocardiographic and electrophysiologic characteristics

Localizing the origin of focal atrial tachycardia by combining clinical characteristics with P-wave morphology

Background

Analyzing the P-wave morphology of an electrocardiogram (ECG) may determine the origin of focal atrial tachycardia (AT), thereby providing information for mapping and ablation.

Objective

We sought to analyze the ECG and clinical characteristics of focal ATs with different origins and to improve the 2021 Kistler algorithm.

Methods

We included 226 focal AT patients treated with radiofrequency catheter ablation. The origin of AT was determined by intracardiac electrophysiological examination. The diagnostic value of the 2021 Kistler algorithm was evaluated. The ECG and clinical characteristics of frequently misidentified cases were compared with those of patients with AT originating from adjacent locations. The algorithm was then modified and re-evaluated.

Results

The sensitivity of the Kistler algorithm for the diagnosis of left atrial appendage (LAA), left pulmonary vein (LPV), and right atrial appendage origins was 62.5%, 61.1%, and 52.9%, respectively. An incessant attack was a common feature of atrial appendage origins (P < .05). Focal AT originating from the LPV was more likely to be accompanied by atrial fibrillation than one originating from the LAA (P < .05). The algorithm was modified based on these results. The sensitivity of the new algorithm for distinguishing origins in the LAA, LPV, and right atrial appendage was 75.0%, 61.1%, and 70.6%; the specificity was 95.0%, 96.6%, and 95.0%; and the accuracy was 94.2%, 93.8%, and 96.9%, respectively.

Conclusion

The presence of atrial fibrillation and the incessancy of the attack can aid in distinguishing focal ATs originating from pulmonary veins and atrial appendages from those originating from adjacent locations.

Utility of dual-chamber Electrogram-based pace mapping in a teenager with a focal atrial tachycardia, low inducibility, and indeterminate earliest excitation site

A 17-year-old patient presented with frequent palpitations, where the tachycardia was not sustained and could not be induced, making it impossible to pinpoint the earliest activation site using the activation map. However, by utilizing a dual-chamber electrogram-based pace mapping technique, we successfully identified the origin and achieved effective treatment.