The T wave is a component of the electrocardiogram (ECG or EKG) that represents the repolarization of the heart's ventricles. This phase occurs after the heart muscle has contracted and is essential for the heart to reset and prepare for the next heartbeat. The T wave typically follows the QRS complex, which indicates ventricular contraction. In a normal ECG, the T wave is usually upward and rounded, but its shape can vary based on several factors, including heart health, electrolyte levels, and medications. Abnormalities in the T wave can indicate various cardiac conditions, making it an important aspect of cardiac monitoring.