Question

During analysis of the pt's EKG, you note the presence of more P waves than QRS complexes. You also note all PR intervals have a uniform length, but random QRS complexes are dropped. What type of AV block is most likely present?

Answer 1

The EKG findings with more P waves than QRS complexes, consistent PR intervals, and randomly dropped QRS complexes most likely indicate a second-degree AV block, specifically Mobitz Type II.

Step-by-step explanation:

The presence of more P waves than QRS complexes, with uniform PR intervals but random dropping of QRS complexes indicates a second-degree AV block, specifically Mobitz Type II or second-degree type II atrioventricular block. This type of block occurs when some, but not all, atrial electrical impulses fail to conduct through the AV node and result in a QRS complex. Unlike a third-degree AV block where there is no correlation between P waves and QRS complexes, in a second-degree Mobitz Type II block, the PR interval remains constant before a QRS complex is dropped. It is important to distinguish this second-degree AV block from Mobitz Type I (Wenckebach) where there is a progressive elongation of the PR interval until a beat is dropped.