Which phase of the cardiac cycle is represented by the T wave on an ECG?

The T wave on an electrocardiogram (ECG) represents ventricular repolarization, which is the phase of the cardiac cycle when the ventricular muscles recover from depolarization and prepare for the next heartbeat. During this phase, the electrical activity that led to the previous contraction is reversed, allowing the heart muscle to relax and refill with blood before the next contraction occurs.

Understanding the T wave is crucial because it indicates how well the heart is functioning and recovering. Abnormalities in the T wave can signal issues with the heart's repolarization process, which can be indicative of various cardiac conditions. The T wave follows the QRS complex, which represents ventricular depolarization—this is the phase when the ventricular muscles contract to pump blood out of the heart. Thus, the T wave effectively marks the completion of one cardiac cycle before it begins anew.