From the Guidelines
Hyperkalemia on an ECG typically shows several characteristic changes, including peaked T waves, PR interval prolongation, P wave flattening, QRS complex widening, and ST segment depression, with the earliest sign being tall, peaked T waves, as noted in the study by 1. These changes reflect potassium's effect on cardiac cell membrane potential, which alters the speed of depolarization and repolarization. The progression of ECG changes generally correlates with serum potassium levels:
- mild hyperkalemia (5.5-6.5 mEq/L) shows peaked T waves
- moderate hyperkalemia (6.5-8.0 mEq/L) demonstrates P wave changes and PR prolongation
- severe hyperkalemia (>8.0 mEq/L) causes QRS widening and the sine wave pattern, as described in the study by 1. Recognizing these ECG patterns is crucial for prompt diagnosis and treatment of hyperkalemia, which can lead to life-threatening arrhythmias if left untreated, as highlighted in the study by 1. Some key points to consider when interpreting ECG changes in hyperkalemia include:
- The ECG changes can be highly variable and not as sensitive as a laboratory test in predicting hyperkalemia or its associated complications, as noted in the study by 1.
- The presence of peaked T waves is one of the most common findings on ECG for patients with hyperkalemia, as described in the study by 1.
- The classification of hyperkalemia as mild, moderate, or severe helps illustrate the progressive effect on the ECG, as discussed in the study by 1. It is essential to prioritize the diagnosis and treatment of hyperkalemia based on the severity of the ECG changes and the patient's clinical presentation, as emphasized in the study by 1.
From the Research
Hyperkalemia on ECG
- Hyperkalemia can manifest on an electrocardiogram (ECG) in several ways, including peaking of the T waves, although this is rarely a sign of life-threatening hyperkalemia 2
- The ECG can be a crucial diagnostic tool in identifying patients with potentially lethal hyperkalemia, especially in critically ill patients 2
- Other clinical-electrocardiographic manifestations can help identify patients with hyperkalemia who require prompt intervention, as outlined in studies on the electrocardiographic manifestations of severe hyperkalemia 2
Key ECG Signs
- Peaking of the T waves is the most widely appreciated ECG sign of hyperkalemia, but it is not typically a manifestation of life-threatening hyperkalemia 2