VT Ablation: Importance of Linear Lesions and Late Potentials

A reentrant mechanism related to a ventricular scar is the main mechanism of monomorphic VT in the setting of structural heart diseases. The surviving muscles in the scar areas are the main targets for VT ablation, identified as fragmented and late potentials. Identification of critical fibers involved in the circuit is usually performed during stable VT by using traditional entraining techniques. However, since many patients present hemodynamic instability, nonsustained VTs, or multiple morphologies, substrate mapping during sinus rhythm is an acceptable strategy for such patients. Electroanatomic mapping is an essential tool for identifying the possible channels that are targeted by endocardial and epicardial RF linear lesions. Such strategy produces a marked reduction in VT recurrences being increasingly applied for patients with unmappable VT and may be combined with other mapping approaches in patients with mappable VTs.