Ventricular Tachycardia Ablation Using Map Merge Capable of Integrating Multiple Sessions

This case report presents a novel approach for ventricular tachycardia (VT) ablation in a patient with cardiac sarcoidosis, utilizing the Map Merge function of the CARTO 3 system to integrate mapping data from multiple ablation sessions. A 62-year-old male with recurrent VT underwent initial endocardial ablation, where voltage mapping revealed no low-voltage areas (LVA) in the endocardium, though pace mapping matched clinical VT morphology. Fragmentation potentials were noted in the coronary vein, indicating a probable epicardial substrate. Ablation successfully suppressed VT, but recurrence occurred within 4 days, prompting a second, epicardial approach. During this session, voltage mapping identified broad LVAs with late potentials in the epicardium, aligning with prior endocardial sites. The Map Merge function enabled superimposing maps from both sessions, confirming spatial consistency between endocardial and epicardial LVAs and enhancing the precision of ablation targeting. Post-ablation, no VT recurrence was observed.This case underscores the clinical value of Map Merge, which improves procedural accuracy by integrating data across temporally distinct sessions, especially in VT cases involving epicardial substrates. By enabling comprehensive mapping without repeated epicardial mapping, Map Merge facilitates efficient identification and alignment of LVAs and abnormal potentials. This approach may improve outcomes in VT ablation by ensuring precise targeting, particularly in cases requiring endo-epicardial intervention.