What ECG pattern is typically seen with hypokalemia, and what risk does it pose?

What ECG pattern is typically seen with hypokalemia, and what risk does it pose?

• A. Flattened or inverted T waves with prominent U waves; increased risk of arrhythmias, including torsades de pointes with QT prolongation
• B. Tall, peaked T waves progressing to wide QRS
• C. ST-segment elevation
• D. Shortened QT interval

Answer: (A)

Hypokalemia changes how the heart repolarizes, and those changes show up on the ECG as flattening or inversion of the T waves and the appearance of prominent U waves after the T wave. The QT interval is often prolonged because repolarization is delayed. This combination signals a higher risk for ventricular arrhythmias, especially torsades de pointes, which can occur when the QT is prolonged and the heart is prone to abnormal rapid beats. Torsades is a specific, potentially life-threatening rhythm that can degenerate into more dangerous rhythms if the potassium deficit isn’t corrected. Other patterns don’t fit hypokalemia: very tall, peaked T waves point to high potassium; ST-segment elevation is classic for acute injury like a heart attack or pericarditis; a shortened QT interval is more typical of high potassium or high calcium states.

Hypokalemia changes how the heart repolarizes, and those changes show up on the ECG as flattening or inversion of the T waves and the appearance of prominent U waves after the T wave. The QT interval is often prolonged because repolarization is delayed. This combination signals a higher risk for ventricular arrhythmias, especially torsades de pointes, which can occur when the QT is prolonged and the heart is prone to abnormal rapid beats. Torsades is a specific, potentially life-threatening rhythm that can degenerate into more dangerous rhythms if the potassium deficit isn’t corrected.

Other patterns don’t fit hypokalemia: very tall, peaked T waves point to high potassium; ST-segment elevation is classic for acute injury like a heart attack or pericarditis; a shortened QT interval is more typical of high potassium or high calcium states.