Noninvasive epicardial and endocardial electrocardiographic imaging of scar-related ventricular tachycardia

An effective treatment for scar-related ventricular tachycardia (VT) is to interrupt the circuit by catheter ablation. If activation sequence and entrainment mapping can be performed during sustained VT, the exit and isthmus of the circuit can often be identified. However, with invasive catheter mapping, only monomorphic VT that is hemody namically stable can be mapped in this manner. A non-invaive approach to fast mapping of unstable VTs can potentially allow an improved identification of critical ablation sites. In this pilot study, noninvasive ECG-imaging were carried out on patients with unstable scar-related VT. The reconstructed reentry circuits correctly revealed both epicardial and endocardial origins of activation, consistent with locations of exit sites found during ablation procedures. The results also indicated that some reentry circuits involve both epicardial and endocardial layers, and can only be properly interpreted by mapping both layers.