In a normal ECG, the P waves are:

• A. In front of QRS complexes
• B. After QRS complexes
• C. Absent
• D. Not related to QRS timing

Answer: (A)

The timing of the P wave reflects atrial depolarization happening before ventricular depolarization. In a normal ECG, the P wave appears before each QRS complex because the sinus impulse travels through the atria first, triggering atrial contraction, then reaches the AV node for a brief delay, and finally depolarizes the ventricles to produce the QRS complex. So the best statement is that P waves are in front of QRS complexes. If P waves were after the QRS, or absent, that would indicate an abnormal rhythm or conduction issue, and saying they’re not related to QRS timing would ignore the established sequence of atrial then ventricular activation.