Atrial tachycardia (AT) is increasingly observed in patients, particularly in the context of atrial fibrillation ablation. The exact electrophysiological mechanisms are not easy to establish but a practical approach consists in distinguishing macroreentries from focal ATs as this is crucial for the ablation strategy. In centrifugal arrhythmias (such as focal AT and localized reentry), the activation originates from a source and spreads centrifugally to the rest of the atria, while in macroreentries, it follows a large path around a central obstacle and reenters. The analysis of the surface electrocardiogram is of limited value to predict the macroreentrant or focal nature of the arrhythmia. Antiarrhythmic drugs are usually tried first and in case of failure, catheter ablation is considered, with or without the support of a localization/mapping system. The most challenging cases are those with multifocal AT as they are poorly responsive to drugs, difficult to ablate, and arise in patients in poor medical conditions. New technologies such as high-density mapping and non-invasive mapping may facilitate the identification of mechanisms and target(s) for catheter ablation.
Pattern and Timing of the Coronary Sinus Activation to Guide Rapid Diagnosis of Atrial Tachycardia After Atrial Fibrillation Ablation
