Which wave on the ECG represents ventricular muscle repolarization?

The T-wave on an ECG represents ventricular muscle repolarization, which is a crucial part of the cardiac cycle. After the ventricles have contracted and ejected blood (as indicated by the QRS complex), the muscle cells within the ventricles must return to their resting state. This repolarization process is depicted by the T-wave.

During the T-wave, the electrical activity reflects the recovery of the ventricular myocardium as potassium ions move out of the cells, and sodium/calcium ions move back into the cells. This process is vital for the heart to prepare for the next contraction. Therefore, the T-wave is essential for understanding how the heart maintains its rhythm and function throughout each cardiac cycle.

Other components of the ECG, such as the P-wave and QRS complex, represent different phases of the heart's electrical activity. The P-wave marks atrial depolarization, while the QRS complex signifies ventricular depolarization. The PR-interval is a measure of time from the beginning of atrial depolarization to the beginning of ventricular depolarization but does not itself represent repolarization. Understanding these distinctions helps in accurately interpreting ECG results and assessing cardiac health.