Atrial tachycardia has which of the following?

• A. P waves before QRS
• B. P waves after QRS
• C. No P waves
• D. Tall P waves

Answer: (C)

In atrial tachycardia, the impulse starts in atrial tissue outside the SA node, so the atria depolarize before the ventricles respond. That means P waves should be visible and occur before each QRS complex, though their shape may be different from normal sinus P waves because the atrial origin is not the SA node. The rhythm is usually a narrow-complex tachycardia with a faster rate, driven by an atrial pacemaker. The option claiming there are no P waves would point to rhythms like atrial fibrillation or certain ventricular tachycardias, not atrial tachycardia, and the idea of P waves after the QRS would indicate retrograde atrial activation seen in other tachyarrhythmias. Tall P waves reflect atrial enlargement, not the defining pattern of atrial tachycardia.