A condition characterized by a prolonged PR interval more than 0.2 seconds in ECG is called:

HP CHO -9 October 2022

Medical & Surgical Nursing

Easy

Appeared in: HP CHO -9 October 2022

Explanation

First-degree AV block is defined as a delay in conduction from the atria to the ventricles, not a complete block.
The hallmark of this condition on an ECG is a fixed, prolonged PR interval consistently greater than 0.20 seconds (five small squares).
Despite the delay, every P wave is followed by a QRS complex, meaning there are no 'dropped' beats.
The rhythm remains regular, distinguishing it from second and third-degree blocks which are often irregular.

Option A: Second-degree AV block is incorrect because it is characterized by the intermittent failure of atrial impulses to conduct to the ventricles, resulting in 'dropped' QRS complexes. This is a more advanced block than just a prolonged PR interval.
Option B: Mobitz Type II AV block is a specific type of second-degree block. It involves a constant PR interval (which can be normal or prolonged) followed by an unexpectedly dropped QRS complex. It is more serious than a simple prolonged PR interval.
Option D: Complete block, or third-degree AV block, is incorrect because it involves a complete dissociation between atrial (P waves) and ventricular (QRS complexes) activity. The atria and ventricles beat independently of each other.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain ECG Interpretation: Atrioventricular (AV) Blocks as background academic context rather than a clinical decision trigger.
While first-degree AV block is often benign, nurses must assess for potential underlying causes, such as medication side effects (e.g., digoxin, beta-blockers) or electrolyte imbalances.
The primary nursing responsibility is to monitor the patient's ECG for any progression to higher-degree blocks (second or third-degree), which can be life-threatening and may require intervention like pacing.
Patient education is key, especially if the block is new. The nurse should explain the condition in simple terms and advise the patient to report symptoms like dizziness, fainting, or shortness of breath.

How to Approach the Question

First, identify the key clinical finding in the question stem: 'prolonged PR interval more than 0.2 seconds'.
This is a factual recall question. Access your knowledge of ECG interpretation and the definitions of different atrioventricular (AV) blocks.
Systematically evaluate each option against the definition. A PR interval > 0.20 seconds is the specific criterion for a first-degree AV block.
Eliminate options that describe different phenomena. Second-degree and complete blocks are defined by dropped beats or AV dissociation, not just a prolonged PR interval.
Confirm your choice. First-degree AV block is a delay in conduction where every impulse gets through, matching the description perfectly.

Concept Tested & Keywords

Concept Tested: ECG Interpretation: Atrioventricular (AV) Blocks
Stem keywords: prolonged PR interval, more than 0.2 seconds, ECG
Lead-in keywords: is called
Clinical cues: PR interval > 0.2 seconds is the defining feature of first-degree AV block.

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