Dinov B, et al. - Researchers investigated the characteristics of radiofrequency (RF) lesions relative to procedural outcomes following catheter ablation (CA) of ventricular arrhythmias (VA). Cardiac magnetic resonance (CMR) (1.5 T) using gadolinium contrast was performed on patients referred for CA of VA, both before and after ablation. In early gadolinium-enhanced post-ablation CMRs, they measured the volume and transmurality of the RF-induced lesions. Persistently inducible VA at the end of the CA defined acute failure. Non-enhanced lesions resembling the no-reflow phenomenon in myocardial infarction were demonstrated on CMR after VA ablation. Despite being correlated to the ablation energy and impedance drop, the size and the depth of the RF-injury were not found to be related to acute ablation success.