Differences in distribution of fibrosis in the ventricles underlie dominant arrhythmia vulnerability of the right ventricle in senescent mice

For good cardiac function, it is necessary that cardiomyo-cytes are adequately coupled, easily excitable, and that tissue architecture ensures normal impulse propagation. If one or more of these factors are impaired, an arrhythmogenic substrate may arise. Ventricular arrhythmias are considered a major cause of sudden cardiac death. In cardiac diseases such as Brugada syndrome and arrhythmogenic right ventricular dysplasia/cardiomyopathy (ARVD/C), mutations are thought to be present that involve the entire heart. Patients with Brugada syndrome may carry mutations in the cardiac sodium channel Nav1.5, which can affect excitability of cardiomyo-cytes.1 ARVD/C may be related to mutations in desmosomal proteins, which can affect the cell-to-cell coupling.2 Despite the fact that these mutations affect the entire heart, the right ventricle (RV) is usually found to be more vulnerable to arrhythmias than the left ventricle (LV) in Brugada syndrome and ARVD/C. The phenotypes mentioned before often become more pronounced as patients age. …