What is the presence of P waves in Supraventricular Tachycardia (SVT)?

In Supraventricular Tachycardia (SVT), P waves are typically absent or not discernible due to the rapid rates of atrial contraction. SVT arises from circuits in the atria or AV node, where rapid reentrant tachycardias can obscure or eliminate the visibility of these atrial depolarizations on the ECG. The tachycardia causes the atrial electrical activity to blend in with the QRS complexes, making it difficult to identify the P waves clearly, if at all.

While in some cases, P waves may be present and recognizable—particularly in junctional or atrial ectopic tachycardias—the more common presentation of typical SVT is for P waves to be absent because the heart is beating too quickly for them to be separately recognized on the ECG. This is a key characteristic of SVT that differentiates it from other types of tachycardia where P waves may be regular and identifiable.