Cardiac MRI Anatomy and Function as a Substrate for Arrhythmias.

The use of cardiovascular magnetic resonance (CMR) has been implemented in the diagnostic work-up of patients with cardiomyopathies by providing an accurate assessment of biventricular volumes and function and a detailed myocardial tissue characterization in a one-stop-shop multi-parametric imaging technique. Its unique capability to perform an accurate tissue characterization of the myocardium, which is superior to other imaging modalities, has prompt its use in the analysis of myocardial arrhythmic substrates and in the prognostic risk stratification of patients. Although left ventricular ejection fraction (LVEF) has always been the best-known predictor of arrhythmic risk, the quantification of myocardial scar by CMR has been recognised as a powerful risk stratification tool, independent of LVEF. Moreover, due to its ability to identify myocardial arrhythmic substrate, both ventricular but more recently also atrial, CMR is increasingly offered as a guide to ablation procedures.