What does spiked T wave in an ECG suggest about potassium levels?

A spiked T wave on an electrocardiogram (ECG) is indicative of elevated potassium levels in the blood, a condition known as hyperkalemia. The T wave represents the repolarization phase of the cardiac action potential. When levels of potassium are high, it can lead to alterations in the electrical activity of the heart, which are reflected in the waveform of the ECG.

Specifically, hyperkalemia causes an increase in the amplitude and a narrowing of the T wave, giving it a "spiked" appearance. This change occurs because excess potassium affects the conduction system of the heart, leading to faster and disorganized depolarization and repolarization. Monitoring these ECG changes can be crucial for identifying and managing potential heart rhythm disorders related to abnormal potassium levels.

Other options, such as low potassium levels or normal potassium levels, would typically not result in spiked T waves. Instead, low levels may lead to flattened or inverted T waves, while normal potassium levels show expected T wave morphology. High calcium levels do not directly produce spiked T waves but may produce different changes in the ECG trace. Understanding these relationships is essential for clinicians when interpreting ECGs and assessing electrolyte disturbances.