Sinus rhythm is a normal physiological rhythm in humans, which is dominated by impulses from the sinus node. The frequency of normal adult sinus rhythm is 60-100 beats per minute. Complete right bundle branch block is a common type of intraventricular block, which means that the site of intraventricular block occurs in the right bundle branch. Complete right bundle branch block can be seen in a subset of normal individuals or in diseases such as rheumatic heart disease, congenital heart disease with atrial septal defect, coronary atherosclerotic heart disease, hypertension, and chronic pulmonary heart disease. In patients with complete right bundle branch block in sinus rhythm, active treatment of the underlying heart disease, if present, is required; no special treatment is needed for complete right bundle branch block itself.