Multimodality imaging to enhance substrate characterization for ventricular tachycardia ablation: what's new?

Image integration is now widely used to delineate the ventricular tachycardia substrate, and the first randomized data have appeared. We review developments of the past 18 months relevant to the practicing ablationist, with attention to what imaging-defined scar represents and how it should be applied at the bedside.

Imaging-defined scar has been validated against co-registered whole-heart histology, confirming that most CMR channels correspond to bundles of surviving myocytes. Both commercially available platforms identify compact scar but underestimate nonconfluent scar, particularly in the epicardium. Intramyocardial fat rather than fibrosis alone distinguishes arrhythmogenic channel segments, making computed tomography complementary to cardiac magnetic resonance. The first randomized trial of image integration (InEurHeart) demonstrated that computed tomography-guided ablation shortened procedures without compromising safety. The landscape of image integration continues to evolve. Photon-counting detector computed tomography has entered clinical comparison, and digital twin-guided ablation has reached first clinical use.

Imaging modality selection should follow aetiology, with intracardiac echocardiography used adjunctively wherever available. Advances in imaging protocols and integration offer novel toolkits for the clinician ablating ventricular tachycardia targets. Future studies should remember to validate image integration against mapped or surmised ventricular tachycardia circuits.