Raphael CE, Liew AC, Mitchell F, et al. - Researchers evaluated the factors predictive of atrial fibrillation (AF) in hypertrophic cardiomyopathy (HC), by performing cardiovascular magnetic resonance (CMR), with a special focus on the role of myocardial fibrosis. They analyzed prospectively enrolled consecutive patients with HC referred for CMR 2003 to 2013. They assessed CMR parameters such as left ventricular volumes, presence and percentage of late gadolinium enhancement in the left ventricle (%LGE) and left atrial volume index (LAVi). Findings revealed that AF in patients with HC was independently predicted by the extent of ventricular fibrosis and LA volume. This indicates a mechanistic association between fibrosis and future AF in HC. In risk stratification for AF, CMR with quantification of fibrosis was shown to have incremental worth over LV and LA measurements. The application of a risk prediction score may enable detection of patients carrying a high risk of future AF who may benefit from more intensive rhythm monitoring and a lower threshold for oral anticoagulation.