The ECG image given below shows:

Appeared in: DSSSB October 2024

Explanation

The ECG strip displays a rapid, wide-complex tachycardia, indicating a ventricular origin.
The key feature is the morphology of the QRS complexes, which continuously change in shape, amplitude, and electrical axis.
This pattern, where the peaks of the QRS complexes appear to twist around the isoelectric baseline, is the classic presentation of Torsades de Pointes, a form of polymorphic ventricular tachycardia.
This rhythm is distinct from monomorphic VT, where all QRS complexes look the same, and from atrial arrhythmias, which typically have narrow QRS complexes.

Option A: Atrial fibrillation is characterized by an irregularly irregular rhythm with no clear P waves and usually a narrow QRS complex. The provided ECG shows wide, somewhat organized (though twisting) complexes.
Option B: Monomorphic VT involves wide QRS complexes, but they are uniform (mono-morphic) in shape and size because they originate from a single ectopic focus in the ventricles. The ECG clearly shows varying (polymorphic) QRS shapes.
Option D: Atrial flutter is recognized by its characteristic 'sawtooth' flutter waves (best seen in leads II, III, aVF) and a regular or variably regular rhythm, typically with narrow QRS complexes. These features are absent in the image.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain ECG Interpretation: Ventricular Arrhythmias as background academic context rather than a clinical decision trigger.
Polymorphic VT (Torsades de Pointes) is a medical emergency as it can quickly deteriorate into ventricular fibrillation (VF) and result in sudden cardiac death.
The immediate nursing priority is to assess the patient's hemodynamic stability (i.e., check for a pulse). Management differs significantly for stable versus unstable patients.
The first-line pharmacological treatment for Torsades de Pointes is intravenous magnesium sulfate. It is crucial to identify and discontinue any offending QT-prolonging medications.

How to Approach the Question

First, analyze the rhythm's rate. It is clearly a tachycardia (fast rate).
Second, examine the QRS complex width. The complexes are wide (greater than 3 small squares or 0.12 seconds), which points towards a ventricular origin.
Third, observe the morphology of the QRS complexes. Notice that they are not uniform; they vary in shape, height, and direction.
Fourth, look at the overall pattern of the QRS complexes. They appear to be twisting around the isoelectric line.
This systematic analysis—fast rate, wide complexes, and changing, twisting morphology—is the classic presentation of Polymorphic VT, specifically Torsades de Pointes.

Concept Tested & Keywords

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E6 Medicine Harrison 22e Part 1 p. 1997-1999

E6 Medicine Davidson Principles Practice 24e p. 496-498

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