In the presence of PAC, how do early P waves typically appear on an EKG?

When evaluating early P waves in the context of premature atrial contractions (PACs), they commonly appear buried in the T wave of the preceding QRS complex on an EKG. This phenomenon occurs because the PAC effectively interrupts the normal progression of the cardiac cycle, leading to the early depolarization of the atria.

Due to the timing of the PAC, the atrial depolarization takes place during the repolarization phase of the previous heartbeat, resulting in the P wave being obscured by the T wave that represents ventricular repolarization. This creates a scenario in which the P wave may not be distinctly visible on the EKG but can still be identified if closely examined. The presence of PACs causes these early P waves to have a different morphology compared to normal sinus P waves, often making them not readily apparent and thus "buried" in the T wave.

In contrasts to other options, such as P waves being wide and notched or inverted, these would indicate different cardiac conditions or types of atrial activity that are not typical characteristics seen in PAC scenarios.