P-wave morphology can be used to localize the origin of an arrhythmia. which choice best reflects this utility?

• A. It helps locate the focus of the arrhythmia
• B. It has no diagnostic value
• C. It only indicates ventricular origin
• D. It is useful only in pauses

Answer: (A)

P-wave morphology reflects how the atria are activated, so examining the shape and direction of P waves across the ECG leads reveals where in the atria the impulse starts. By assessing whether P waves are upright or inverted in various leads and their relative timing, you can infer the atrial region acting as the arrhythmia’s origin, which is directly what localizes the source. This is meaningful for atrial arrhythmias and helps guide diagnosis and management. It’s not about the ventricles, and P-wave information has diagnostic value during sustained or paroxysmal atrial rhythms, not just pauses.