A nurse is caring for an assigned client in the ICU. The nurse notices on the cardiac monitor a prominent U wave and ST segment depression. This finding is usually seen in?

1. A

   Hyperkalemia

2. B

   Hypokalemia

3. C

   Hypocalcemia

4. D

   Hypercalcemia

Appeared in: AIIMS Delhi NO - 2018

Explanation

• Hypokalemia (low potassium) alters the repolarization phase of the cardiac action potential.
• This delayed repolarization manifests on the ECG as a flattened T wave, ST-segment depression, and a characteristic prominent U wave.
• The U wave, a small deflection following the T wave, becomes abnormally large in hypokalemia and is a key diagnostic clue.
• The image provided shows a classic example of these ECG changes, confirming the diagnosis.

Why Other Options Were Wrong

• Option A: Hyperkalemia (high potassium) presents with different ECG changes.
• Option C: Hypocalcemia (low calcium) primarily affects the duration of the ST segment.
• Option D: Hypercalcemia (high calcium) has the opposite effect of hypocalcemia on the QT interval.

Related Visual

Clinical Relevance

• Nursing practice connection: Prioritize focused assessment, early escalation, and real-time monitoring when managing Interpretation of ECG findings in electrolyte imbalances in acute care settings.
• A nurse's ability to quickly recognize ECG changes associated with electrolyte imbalances is a critical patient safety skill, especially in the ICU setting.
• Upon noticing signs of hypokalemia on the monitor, the nurse's priority is to assess the patient, check recent lab values, and immediately notify the healthcare provider, as severe hypokalemia can lead to fatal arrhythmias.
• Nursing interventions include preparing for potassium replacement (oral or IV), continuous cardiac monitoring, and assessing for other symptoms like muscle weakness and respiratory depression.

How to Approach the Question

• First, identify the key findings presented in the clinical scenario: 'prominent U wave' and 'ST segment depression'.
• Recognize that these are specific ECG abnormalities.
• Access your knowledge of how different electrolyte imbalances affect the ECG.
• Systematically evaluate the options: Recall that hyperkalemia causes peaked T waves, hypocalcemia prolongs the QT interval, and hypercalcemia shortens it.
• Conclude that the combination of a prominent U wave and ST depression is the classic presentation for hypokalemia.

Concept Tested & Keywords

• Concept Tested: Interpretation of ECG findings in electrolyte imbalances.
• Stem keywords: ICU, cardiac monitor, prominent U wave, ST segment depression
• Lead-in keywords: usually seen in
• Clinical cues: The combination of a prominent U wave and ST depression is a hallmark sign pointing to a specific electrolyte imbalance.

Question ID

QH0S3WFUqQokYt-uuxMAFL

Copy ID

Reference Book

E6 Medicine Harrison 22e Part 1 pp. 1916-1918, 1911-1913

E6 Gynecology Williams p. 64-85