CPR and defibrillation should be initiated in which kind of arrhythmia?

AIIMS Nagpur NO - 2018

Pharmacology

Easy

Appeared in: AIIMS Nagpur NO - 2018

Explanation

Ventricular fibrillation (VF) is a chaotic electrical rhythm in the ventricles, causing them to quiver instead of contracting effectively.
This lack of contraction results in no blood being pumped from the heart (no cardiac output), leading to sudden cardiac arrest.
Cardiopulmonary Resuscitation (CPR) is essential to manually circulate oxygenated blood to the brain and other vital organs, acting as a bridge to definitive treatment.
Defibrillation is the definitive treatment for VF. It involves delivering a high-energy electrical shock to the heart to stop the chaotic activity and allow the heart's natural pacemaker to re-establish a perfusing rhythm.

Option A: Premature ventricular contractions (PVCs) are isolated ectopic beats and do not represent a state of cardiac arrest. They do not cause a loss of pulse and therefore do not require CPR or defibrillation.
Option B: Atrial fibrillation is a supraventricular arrhythmia. While it can cause rapid heart rates and symptoms, it does not inherently cause pulseless cardiac arrest. CPR and defibrillation are not the primary treatments for atrial fibrillation itself.
Option D: Atrioventricular (AV) block is a disorder of electrical conduction, often causing a slow heart rate (bradycardia). If it progresses to cardiac arrest (usually asystole), CPR is performed, but defibrillation is not indicated. The definitive treatment for severe, symptomatic AV block is cardiac pacing.

Visual 1: ECG Strips - Comparison of ECG tracings for Normal Sinus Rhythm, Ventricular Fibrillation, Atrial Fibrillation, and PVCs to highlight the chaotic, disorganized waveform of VF.
Visual 2: Flowchart - ACLS Cardiac Arrest Algorithm showing the two main pathways: Shockable Rhythms (VF/Pulseless VT) and Non-Shockable Rhythms (Asystole/PEA).

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Recognition and immediate management of life-threatening cardiac arrhythmias as background academic context rather than a clinical decision trigger.
Rapid identification of VF on a cardiac monitor is a critical nursing skill in emergency and critical care settings, as immediate action is required to save a patient's life.
The 'Chain of Survival' concept highlights that early recognition, early CPR, and rapid defibrillation are the most critical factors for improving survival rates from VF-induced cardiac arrest.
What if? If the rhythm was asystole (a flat line), defibrillation would be contraindicated and ineffective. The correct intervention would be to continue high-quality CPR and administer medications like epinephrine while searching for and treating reversible causes (the 'H's and T's').

How to Approach the Question

First, identify the key actions in the question: 'CPR and defibrillation'.
Recognize that this specific combination of interventions is the standard treatment for a life-threatening cardiac arrest caused by a 'shockable' rhythm.
A shockable rhythm is one where the heart has chaotic but organized electrical activity that can potentially be reset by an electrical shock.
Evaluate each option against this requirement. Premature ventricular contractions, atrial fibrillation, and atrioventricular block are not primary shockable cardiac arrest rhythms.
Conclude that Ventricular Fibrillation is the classic example of a shockable rhythm that requires immediate CPR and defibrillation.

Concept Tested & Keywords

Concept Tested: Recognition and immediate management of life-threatening cardiac arrhythmias.
Stem keywords: CPR, defibrillation, arrhythmia
Lead-in keywords: initiated in which
Negative lead-in flag: false

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