<prompt> The T wave on an ECG tracing represents which of the events in the cardiac cycle?Atrial depolarizationAtrial repolarizationVentricular depolarizationVentricular repolarization  <response>: The T wave represents ventricular repolarization and is longer in duration than depolarization i.e., conduction of the repolarization wave is slower than the wave of depolarization. The P wave represents the wave of depolarization that spreads from the SA node throughout the atria, and is usually 0.08 to 0.1 seconds 80-100 ms in duration. The QRS complex represents ventricular depolarization. The Q-T interval represents the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential. 