TCRN Practice Exam 2025 – Complete Prep for Your Test

The P wave in an ECG tracing specifically represents the electrical activity associated with atrial contraction, also known as atrial depolarization. When the atria contract, they push blood into the ventricles, and this activity is captured as a positive deflection on the ECG tracing. This wave is crucial for understanding the timing of the cardiac cycle, as it reflects the start of the cardiac cycle preceding the ventricular contraction.

The R wave, which is a component of the QRS complex, indicates ventricular depolarization, not atrial contraction. The T wave represents ventricular repolarization, the process by which the ventricles reset after contraction. The U wave, although less commonly seen, may be related to repolarization of the papillary muscles or other cardiac structures but is not associated with atrial contraction. Therefore, the P wave is distinctly linked to atrial activity in the cardiac cycle.