Functional Substrate Mapping Using Atrial Decrement Evoked Potentials to Predict Critical Isthmus of Atrial Tachycardia.

Recent reports highlighted the role of functional substrate mapping during sinus rhythm to predict the critical isthmus of left atrial tachycardias (AT). In this article, we reported a case of a 63-year-old female patient who was admitted with recurrent AT after pulmonary vein isolation. Although sinus rhythm revealed normal left atrium voltages, programmed stimulation with extrastimulus revealed decrement evoked potentials with prolongation in local electrograms on the anterior wall. Critical isthmus of AT was colocalized with deceleration zones during functional substrate mapping. Radiofrequency ablation successfully terminated AT.