A first-degree block, also known as first-degree atrioventricular (AV) block, is a type of heart condition where the electrical signals traveling from the atria to the ventricles are delayed. This delay can be seen on an electrocardiogram (ECG) as a prolonged PR interval, which is the time it takes for the electrical impulse to travel through the AV node. In most cases, first-degree block is considered benign and does not require treatment. It can occur in healthy individuals, especially athletes, and may also be associated with certain medications or underlying heart conditions. Regular monitoring is usually sufficient to ensure that it does not progress to a more serious block.