Wenckebach block, also known as type I atrioventricular (AV) block, is a condition where the electrical signals in the heart are progressively delayed until one signal is completely blocked. This results in a missed heartbeat. It typically occurs in the AV node, which is responsible for transmitting signals from the atria to the ventricles. This type of block is often seen in healthy individuals and can be caused by factors such as medications, increased vagal tone, or ischemic heart disease. While it may not always require treatment, monitoring is essential to ensure it does not progress to more severe forms of heart block.