Which AV block is also referred to as Mobitz-II?

RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Medical & Surgical Nursing

Easy

Appeared in: RRB Nsg. Superintendent 21 July 2019 (shift 1st)

Explanation

Second-Degree AV block is characterized by the intermittent failure of atrial impulses to conduct to the ventricles.
This type of block is subdivided into two main types: Mobitz Type I (Wenckebach) and Mobitz Type II.
Mobitz Type II involves a constant PR interval before intermittently non-conducted P waves (dropped beats).
Because Mobitz II is a classification within Second-Degree AV block, this is the correct overarching category.

Option A: Complete Heart Block is another name for Third-Degree AV Block, not Second-Degree AV Block Mobitz II.
Option C: Third-Degree AV Block, or Complete Heart Block, involves a complete dissociation between atrial and ventricular activity. This is a more severe condition than Mobitz II.
Option D: First-Degree AV Block involves a prolonged PR interval but no dropped beats. Mobitz II is defined by the presence of dropped beats.

Visual 1: ECG Strip - An ECG showing Second-Degree AV Block, Mobitz Type II, with a constant PR interval and a non-conducted P wave (a P wave not followed by a QRS complex).
Visual 2: Diagram - A flowchart illustrating the classification of AV blocks from First-Degree to Third-Degree, highlighting the position of Mobitz I and Mobitz II under Second-Degree block.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Classification of Atrioventricular (AV) Blocks as background academic context rather than a clinical decision trigger.
Mobitz Type II AV block is considered clinically significant and potentially dangerous because it can suddenly progress to Third-Degree (complete) heart block, leading to severe bradycardia or asystole.
Nurses must be able to differentiate between Mobitz I and Mobitz II on an ECG, as the management differs significantly. Mobitz II often requires permanent pacemaker implantation, even in asymptomatic patients.
What if? If a patient with Mobitz II block suddenly becomes dizzy and hypotensive, the nurse's priority is to assess for progression to complete heart block, initiate emergency measures (like applying transcutaneous pacing pads), and notify the physician immediately.

How to Approach the Question

First, identify the key term in the question: 'Mobitz-II'.
Recall the classification system for atrioventricular (AV) heart blocks.
Remember that AV blocks are categorized into first-degree, second-degree, and third-degree.
Place 'Mobitz-II' within this classification. It is a subtype of Second-Degree AV Block.
Evaluate the given options. 'Second Degree AV Block' is the correct category that includes Mobitz-II.
Eliminate the other options based on their definitions: First-Degree (delay, no dropped beats) and Third-Degree/Complete (complete dissociation).

Concept Tested & Keywords

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