Which ECG finding is associated with hypokalemia?

Which ECG finding is associated with hypokalemia?

• A. Tall T waves
• B. ST elevation
• C. U waves
• D. Peaked P waves

Answer: (C)

Low potassium levels disrupt ventricular repolarization, lengthening the phase when the heart returns to baseline after each beat. The hallmark ECG change you look for in hypokalemia is the appearance of U waves—small, extra deflections that follow the T wave. These U waves become more prominent as potassium falls and are best seen in the precordial leads (often V2–V4). You may also notice flattened or inverted T waves and some ST-segment depression, but the distinctive sign linked to low potassium is the U wave. Tall T waves point to hyperkalemia, ST elevation suggests acute myocardial injury or pericarditis, and peaked P waves are not characteristic of potassium disturbances.

Low potassium levels disrupt ventricular repolarization, lengthening the phase when the heart returns to baseline after each beat. The hallmark ECG change you look for in hypokalemia is the appearance of U waves—small, extra deflections that follow the T wave. These U waves become more prominent as potassium falls and are best seen in the precordial leads (often V2–V4). You may also notice flattened or inverted T waves and some ST-segment depression, but the distinctive sign linked to low potassium is the U wave. Tall T waves point to hyperkalemia, ST elevation suggests acute myocardial injury or pericarditis, and peaked P waves are not characteristic of potassium disturbances.