From the Guidelines
Hypokalemia on an EKG is characterized by broadening of the T waves, ST-segment depression, and prominent U waves, as well as various arrhythmias, including first or second-degree atrioventricular block, atrial fibrillation, and ventricular arrhythmias 1. The EKG findings of hypokalemia can be classified based on the severity of the condition, which is typically categorized as mild (3.0–3.5 mEq/L), moderate (2.5–2.9 mEq/L), or severe (<2.5 mEq/L) 1. Some key points to consider when evaluating EKG findings in hypokalemia include:
- The appearance of U waves, which are small, positive deflections after the T wave
- ST segment depression, which can be a sign of hypokalemia
- Various arrhythmias, including first or second-degree atrioventricular block, atrial fibrillation, and ventricular arrhythmias, such as premature ventricular contractions, ventricular tachycardia, and torsades de pointes 1. It is essential to recognize these EKG patterns to promptly diagnose and treat hypokalemia, as it can predispose patients to dangerous arrhythmias, particularly in those taking digitalis or with underlying heart disease 1.
From the Research
EKG Findings of Hypokalemia
The EKG findings of hypokalemia include:
- Dynamic changes in T-wave morphology 2
- ST-segment depression 2
- U waves, which are often best seen in the mid-precordial leads (V2–V4) 2
- Prolonged PR interval 2
- Increased amplitude of the P wave 2
- Bifid T-waves, which can be distinguished from other conditions such as coronary artery disease or pericarditis 3
Comparison with Other Conditions
It is essential to note that EKG changes in hypokalemia can be subtle and may receive less attention than the more striking features of hyperkalemia 3. However, recognizing these changes is crucial for differential diagnoses.
Reversal of EKG Changes
The EKG changes in hypokalemia can be reversed when potassium levels are normalized 3. This highlights the importance of monitoring and managing potassium levels, especially in patients with cardiovascular disease 4.