Which side are you on? - Deducing the chamber of origin of atrial tachycardia

Area of Science:

• Cardiology
• Electrophysiology
• Cardiac Electrophysiology

Background:

• Atrial arrhythmias originating from anatomically close regions can complicate electrophysiological mapping and ablation.
• Distinguishing between right and left atrial tachycardia is crucial for effective treatment.

Purpose of the Study:

• To describe a case of left atrial tachycardia that initially presented as right atrial tachycardia.
• To elucidate the mechanism behind abnormal electrograms observed in the right atrium during this condition.
• To enhance understanding of the phenomenon of double potentials in atrial arrhythmias.

Main Methods:

• Case report detailing electrophysiological study findings.
• Analysis of intracardiac electrograms from the right and left atria.
• Correlation of electrogram characteristics with anatomical location and arrhythmia mechanism.

Main Results:

• A patient presented with tachycardia initially suggestive of right atrial origin.
• Electrograms in the right atrium exhibited abnormal patterns, mimicking a right atrial source.
• Further analysis revealed the tachycardia originated from the left atrium, with specific electrogram features explaining the initial misinterpretation and the presence of double potentials.

Conclusions:

• Left atrial tachycardia can mimic right atrial tachycardia due to complex electrophysiological wavefronts.
• Understanding the origin of abnormal electrograms, such as double potentials, is key to accurate diagnosis.
• This case underscores the importance of detailed electrophysiological analysis for complex atrial arrhythmias.