What is observed on EKG with PAT accompanied by AV block?

What is observed on EKG with PAT accompanied by AV block?

• A. A ratio of 2:1 P waves to QRS complexes
• B. Flat P waves
• C. Normal Sinus rhythm
• D. Polymorphic QRS complexes

Answer: (A)

In the case of paroxysmal atrial tachycardia (PAT) accompanied by an AV block, it is typical to observe a specific relationship between the P waves and the QRS complexes on the EKG. The correct observation of a 2:1 ratio of P waves to QRS complexes indicates that for every two P waves, there is one QRS complex being conducted. This reflects the presence of a blockage where not all atrial impulses are conducted to the ventricles, hence leading to more P waves than QRS complexes.

The occurrence of a 2:1 AV block specifically suggests that the atrial rate is higher than the ventricular rate due to the extra P waves resulting from the PAT, while the block limits the number of impulses that reach the ventricles. This creates a characteristic pattern that helps in identifying the AV block in the context of PAT. Observing this ratio allows healthcare providers to infer not only the rapid atrial activity but also the implications of the conduction disturbance present.