The nurse is reviewing the client's telemetry printout. Which of the following cardiac components should the nurse identify as the role of the P wave?

Rationale: A. Ventricular depolarization is incorrect because this is represented by the QRS complex on the ECG, not the P wave. Ventricular depolarization reflects the electrical impulse spreading through the ventricles, triggering ventricular contraction. B. Early ventricular repolarization is incorrect because this is represented by the ST segment, which occurs after ventricular depolarization (QRS complex) and before the T wave. Repolarization is part of the recovery phase, not the P wave. C. Slow repolarization of ventricular Purkinje fibers is incorrect because repolarization occurs primarily during the T wave, not during the P wave. The Purkinje fibers help conduct the impulse rapidly through the ventricles but do not define the P wave. D. Atrial depolarization is correct because the P wave represents the electrical activity that triggers atrial contraction. It is the first positive deflection on a standard ECG, indicating that the SA node has fired and the atria are depolarizing, which precedes ventricular contraction.