Anatomy, histology, and pathology of the cardiac conduction system—part V

Although morphologic findings in many of the cardiac arrhythmias of acute and chronic disease have been elusive, the correlates of heart block (particularly atrioventricular block) are abundant. Pathologic features of sinoatrial, atrioventricular, and bundle‐branch block are reviewed. Lev and Lenegre diseases (idiopathic bilateral bundle‐branch fibrosis) are also reviewed.