Unraveling the Scar With Cardiac Magnetic Resonance

Currently, the decision to implant an implantable cardiac defibrillator (ICD) as primary prevention (PP) of sudden cardiac death (SCD) is based on the presence of severe left ventricle dysfunction and the New York Heart Association functional class. However, only a minority of PP patients with an indication for an ICD based on these variables will require ICD therapies during follow-up, especially those experiencing nonischemic cardiomyopathy. Thus, better risk stratification tools are needed to improve the identification of patients at SCD risk who could benefit from ICD implant. See Article by Jablonowski et al Myocardial scar provides the substrate for the vast majority of life-threatening ventricular arrhythmias (VAs) and reentry circuits contained in the scar tissue are essential for ventricular tachycardia to occur. Late gadolinium enhancement (LGE) by Cardiac magnetic resonance (CMR) allows identification and quantification of myocardial scar and enables classification into 2 types of tissues: dense scar and border zone (BZ) depending on the signal intensity produced by LGE. BZ tissue can be distributed around the scar as the transition toward normal myocardium and can also be located in the scar thereby creating corridors of BZ inside the scar that connect with normal myocardium. These BZ corridors have a reasonably good correlation with conducting channels on the electroanatomical maps and have been shown to be the substrate for ventricular tachycardias. …