A nurse who observes absence of P waves and fibrillating waves before each QRS complex on the cardiac monitor will interpret the client's cardiac rhythm as?

Appeared in: SCTIMST Staff Nurse - 2015 (Set-A)

Explanation

The defining feature of Atrial Fibrillation is the replacement of consistent P waves with chaotic, fibrillatory waves (f waves), indicating disorganized atrial activity.
The ventricular rhythm is characteristically "irregularly irregular" because the atrial impulses are conducted to the ventricles at unpredictable intervals.
As seen in the image, the QRS complexes are present and typically narrow, confirming the impulse originates above the ventricles (supraventricular).
The combination of an irregular rhythm and no discernible P waves on the cardiac monitor points directly to Atrial Fibrillation.

Why Other Options Were Wrong

Option A: Sinus tachycardia is incorrect because it is a regular rhythm with a normal P wave preceding every QRS complex; the only abnormality is a heart rate greater than 100 beats per minute.
Option B: Ventricular fibrillation is incorrect as it is a chaotic rhythm with no identifiable waves (P, QRS, or T). The ECG in the question clearly shows discernible QRS complexes.
Option C: Ventricular tachycardia is incorrect because it is characterized by wide (greater than 0.12s), bizarre-looking QRS complexes, and the rhythm is typically regular. The ECG described and shown has narrow QRS complexes and an irregular rhythm.

Related Visual

Clinical Relevance

Nursing practice connection: Safe nursing care depends on performing ECG Interpretation of Cardiac Arrhythmias in the correct sequence, documenting the action clearly, and monitoring for the expected response.
Atrial Fibrillation significantly increases the risk of thromboembolic events, particularly stroke, because blood can stagnate in the quivering atria and form clots.
A key nursing assessment for a patient in AFib is to check for a pulse deficit—the difference between the apical heart rate (auscultated) and the peripheral pulse rate (palpated). A deficit indicates poor perfusion.
Initial management of new-onset AFib focuses on assessing hemodynamic stability, controlling the ventricular rate (e.g., with beta-blockers or calcium channel blockers), and considering anticoagulation to prevent stroke.

How to Approach the Question

First, analyze the question stem to identify the key ECG characteristics provided: 'absence of P waves' and 'fibrillating waves'.
Next, examine the provided ECG image. Systematically assess the rhythm (is it regular or irregular?), identify if P waves are present, and measure the QRS duration (is it narrow or wide?).
Correlate the findings from the text and the image. The text describes no P waves and fibrillating waves. The image shows an irregularly irregular rhythm with a chaotic baseline and no clear P waves.
Evaluate each option against these findings. Atrial Fibrillation is the only rhythm that matches all the described and observed characteristics.
Eliminate the other options based on their defining features: Sinus Tachycardia (regular, has P waves), Ventricular Fibrillation (no QRS), and Ventricular Tachycardia (wide QRS, usually regular).

Concept Tested & Keywords

Concept Tested: ECG Interpretation of Cardiac Arrhythmias
Stem keywords: absence of P waves, fibrillating waves, QRS complex, cardiac monitor, cardiac rhythm
Lead-in keywords: interpret
Clinical cues: ECG findings are the primary data for interpretation.

Question ID

Q3ev534BdnNji7hpF6naGO

Reference Book

E6 Nursing Fundamentals Potter Perry 12e Part 4 p. 234-236

E6 Pharmacology Nursing Lilley 11e Part 2 p. 86-88

E6 Robert Boland, Marcia L. Verduin - Kaplan and Sadock's Comprehensive Text of Psychiatry-Wolters Kluwer Health (2024) (pp 1-16525 of 16525) p. 7321-7323

Practise the full SCTIMST Staff Nurse - 2015 (Set-A)

Attempt every question from this paper in a timed mock, then review the full solution for each one.

Attempt this paper Attempt in the NPrep app