Which condition would most likely present with the absence of P waves?

The absence of P waves is a hallmark characteristic of atrial fibrillation. In this condition, the normal electrical impulses that trigger atrial contraction are disrupted, leading to chaotic electrical activity in the atria. This irregular and rapid heartbeat prevents the atria from properly contracting, resulting in an absence of clearly identifiable P waves on the electrocardiogram (ECG).

Atrial fibrillation is distinct from other conditions where P waves are typically present, even if they might be distorted or appear in a different form. For example, in atrial flutter, P waves may present as sawtooth patterns (often termed “F-waves”), but they are definitely still present. In contrast, both supraventricular tachycardia and sinus tachycardia would also present with identifiable P waves, as these conditions involve a regular rhythm stemming from an active sinus node or ectopic focus that still maintains organized atrial activity. Thus, the absence of P waves strongly indicates atrial fibrillation, making it the correct choice in this scenario.