Abstract: Obstetrician-gynecologists often are the sole providers of health care to female patients. Because cardiovascular disease is the leading cause of death in women in the United States, obstetrician-gynecologists must be aware of the risk factors, symptoms, and signs of cardiovascular disease and arrhythmia. Furthermore, they must be prepared to identify and treat common types of arrhythmia in this population and refer patients to cardiology for specialized care. Understanding the role of pregnancy among women with arrhythmia is critically important to optimize both maternal and fetal outcomes. This monograph discusses the cardiac conduction system and addresses the assessment, diagnosis, and treatment of both pregnant and nonpregnant patients with heart rhythm disorders.