Which of the following electrolyte abnormalities is primarily associated with T wave inversion, ST segment depression, prolonged PR interval and the appearance of a prominent U wave?

1. A

   Hypokalaemia

2. B

   Hyperkalaemia

3. C

   Hypercalcemia

4. D

   Hypocalcaemia

Appeared in: Bihar NHM CHO-2025

Explanation

• Hypokalemia, or low serum potassium, alters the electrical repolarization of the heart's ventricles.
• This alteration manifests on an ECG with characteristic findings: ST-segment depression, flattening or inversion of the T wave, and the appearance of a prominent U wave (a small wave after the T wave).
• A prolonged PR interval may also be present, indicating a delay in atrioventricular (AV) conduction.
• This combination of ECG changes is a classic presentation of hypokalemia.

Why Other Options Were Wrong

• Option B: Hyperkalaemia (high potassium) presents with different ECG changes, most notably tall, peaked ('tented') T waves, a widened QRS complex, and flattening of the P wave.
• Option C: Hypercalcemia (high calcium) primarily affects the QT interval by shortening it, which is the opposite of what is often seen in severe potassium imbalances.
• Option D: Hypocalcaemia (low calcium) is characterized by a prolongation of the QT interval on an ECG, due to lengthening of the ST segment.

Related Visual

• Visual 1: ECG Strip Comparison - An infographic showing four ECG strips side-by-side, each labeled with Hypokalemia, Hyperkalemia, Hypocalcemia, and Hypercalcemia, highlighting the specific wave changes for each condition.
• Visual 2: Diagram - A diagram of a single cardiac cycle (P-QRS-T-U waves) with annotations showing where the changes in hypokalemia occur (depressed ST, inverted T, prominent U, long PR).

Clinical Relevance

• Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Interpretation of ECG findings related to common electrolyte imbalances as background academic context rather than a clinical decision trigger.
• Nurses must be able to recognize ECG changes related to electrolyte imbalances as they can signal life-threatening arrhythmias. Prompt identification and reporting are critical for patient safety.
• Hypokalemia potentiates the effects of digoxin, increasing the risk of digoxin toxicity. Nurses must monitor patients on both medications very closely for signs of toxicity, such as arrhythmias, nausea, and visual disturbances.
• What if? If the patient's ECG showed tall, peaked T waves and a widened QRS complex, the priority nursing action would shift to preparing for emergency treatment of severe hyperkalemia, which might include administering calcium gluconate, insulin with dextrose, and sodium bicarbonate.

How to Approach the Question

• First, identify the key terms in the question stem. The question asks for an electrolyte abnormality associated with a specific set of ECG findings: T wave inversion, ST depression, prolonged PR, and a prominent U wave.
• Second, recall the characteristic ECG changes for the common electrolyte imbalances listed in the options.
• Third, systematically evaluate each option against the ECG findings described in the question.
• Option A (Hypokalemia) is known to cause ST depression, T-wave flattening/inversion, and prominent U waves. This is a strong match.
• Option B (Hyperkalemia) is associated with peaked T waves and wide QRS, which is different.
• Options C and D (Hyper/Hypocalcemia) primarily affect the QT interval, which is not the main feature described.

Concept Tested & Keywords

• Concept Tested: Interpretation of ECG findings related to common electrolyte imbalances.
• Stem keywords: electrolyte abnormalities, T wave inversion, ST segment depression, prolonged PR interval, prominent U wave
• Lead-in keywords: Which of the following

Question ID

Q3KAt26kDCw-dXeYB-UHZ_

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