What is the typical ECG effect of hyperkalemia?

What is the typical ECG effect of hyperkalemia?

• A. Tall peaked T waves with widened QRS
• B. Short QT interval
• C. U waves prominent
• D. Delta waves

Answer: (C)

Hyperkalemia alters how cardiac cells repolarize and conduct. When potassium rises, extracellular K+ makes the resting membrane potential less negative, which shortens the time for repolarization and produces tall, peaked T waves as phase 3 becomes more pronounced. As potassium continues to rise, conduction through the His-Purkinje system slows, leading to PR interval prolongation and widening of the QRS complex. In severe hyperkalemia, the QRS and T waves can merge into a sine-wave pattern, indicating a high risk of malignant arrhythmias. U waves are not a feature of hyperkalemia; prominent U waves are typically seen with hypokalemia. Delta waves relate to pre-excitation syndromes like WPW, not potassium level effects. So the classic ECG change for hyperkalemia is tall, peaked T waves with widening of the QRS complex.

Hyperkalemia alters how cardiac cells repolarize and conduct. When potassium rises, extracellular K+ makes the resting membrane potential less negative, which shortens the time for repolarization and produces tall, peaked T waves as phase 3 becomes more pronounced. As potassium continues to rise, conduction through the His-Purkinje system slows, leading to PR interval prolongation and widening of the QRS complex. In severe hyperkalemia, the QRS and T waves can merge into a sine-wave pattern, indicating a high risk of malignant arrhythmias.

U waves are not a feature of hyperkalemia; prominent U waves are typically seen with hypokalemia. Delta waves relate to pre-excitation syndromes like WPW, not potassium level effects. So the classic ECG change for hyperkalemia is tall, peaked T waves with widening of the QRS complex.