Question

ECG: Second-Degree AV Block - Type I (Mobitz I, Wenckebach heart block)

Which of the following accurately describes the ECG finding known as Second-Degree AV Block - Type I?

A) Gradual prolongation of PR interval until a P wave is blocked
B) Consistent PR interval with occasional blocked P waves
C) Sudden absence of P waves with a regular PR interval
D) Absence of P waves with irregular PR intervals

Answer 1

Second-Degree AV Block - Type I is characterized by a gradual prolongation of the PR interval until a P wave is blocked, discernible as a pattern on an ECG.

Step-by-step explanation:

The ECG finding known as Second-Degree AV Block - Type I, also called Mobitz I or Wenckebach heart block, is accurately described as A) Gradual prolongation of PR interval until a P wave is blocked. This type of AV block is characterized by progressive lengthening of the PR interval on consecutive beats until a beat (P wave) is completely blocked and not followed by a QRS complex. It is a unique pattern that can be recognized on an ECG and differentiates it from other types of heart blocks where the PR interval might have different characteristics.