First-degree AV block is a physiological phenomenon in which the conduction time from the atria to the ventricles is prolonged beyond normal. For example, patients with a slow heart rate and significant symptoms may be treated with oral atropine. If an adolescent presents with first-degree AV block but has no obvious symptoms, it can be considered to be caused by rheumatic fever, and anti-rheumatic treatment can be given. In addition, patients with first-degree AV block without symptoms need to be closely monitored and reviewed, because first-degree can easily turn into second-degree type II AV block or even into third-degree. Once this occurs, close treatment at a hospital is required.