Identify the following ECG graph in the image.

Appeared in: NORCERT 8 Mains-2025

Explanation

The ECG shows an irregularly irregular rhythm, which is the hallmark of atrial fibrillation.
There are no discernible P waves; instead, the baseline is chaotic with fibrillatory (f) waves, indicating multiple ectopic atrial pacemakers.
The QRS complexes are narrow, confirming a supraventricular origin of the rhythm.

Option A: Supraventricular tachycardia (SVT) is characterized by a regular, rapid rhythm, whereas the provided ECG is irregularly irregular.
Option B: Sinus tachycardia is a regular rhythm with a clear P wave preceding every QRS complex. The ECG in the image is irregular and lacks consistent P waves.
Option C: Ventricular tachycardia is defined by wide, bizarre QRS complexes (greater than 0.12 seconds) because the impulse originates in the ventricles. The ECG shows narrow QRS complexes.

Visual 1: Infographic - A side-by-side comparison of ECG strips for Atrial Fibrillation, Sinus Tachycardia, SVT, and Ventricular Tachycardia, with key features like P waves, R-R intervals, and QRS width highlighted for each.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain ECG interpretation of common cardiac arrhythmias as background academic context rather than a clinical decision trigger.
Atrial fibrillation significantly increases the risk of stroke due to the formation of blood clots in the atria. Nurses must monitor for signs of stroke (e.g., facial drooping, arm weakness, speech difficulty) and administer anticoagulant medications as prescribed.
Nursing care for patients with new-onset atrial fibrillation includes monitoring vital signs, assessing for symptoms like palpitations or dizziness, controlling the ventricular rate with medications (e.g., beta-blockers, calcium channel blockers), and preparing for potential cardioversion.
What if the patient with this ECG was also taking digoxin? The nurse must be vigilant for signs of digoxin toxicity (e.g., nausea, vomiting, vision changes, bradycardia), as it can worsen arrhythmias.

How to Approach the Question

First, analyze the rhythm by measuring the R-R intervals. Observe if they are regular or irregular. In this case, they are clearly irregular.
Next, examine the baseline for P waves. Note their absence and the presence of chaotic fibrillatory waves.
Then, assess the QRS complex width. A narrow QRS (less than 0.12s or 3 small squares) points to a supraventricular origin.
Finally, synthesize these findings: an irregularly irregular rhythm with no P waves and narrow QRS complexes is the classic presentation of atrial fibrillation. Compare this with the definitions of the other options to confirm the diagnosis.

Concept Tested & Keywords

QvIMl0Cnrvt2Exo7U5HkRQ

Practise the full NORCERT 8 Mains-2025

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