heart and blood vessel disorders
Overview of Heart Block
Introduction
Heart block is a delay in the conduction of electrical current as it passes through the conduction system of the heart, including the atrioventricular node, bundle of His, or both bundle branches, all of which are located between the atria and the ventricles. Some types of heart block cause no symptoms, but others cause fatigue, dizziness, light-headedness, and/or fainting. Electrocardiography is used to detect heart block. Some people require an artificial pacemaker. (See also Overview of Abnormal Heart Rhythms .) 