Final answer:
High ECF potassium, or hyperkalemia, can delay the rate of ventricular repolarization and increase the height of the T wave on an electrocardiogram (ECG), which can disrupt normal cardiac rhythm and function.
Step-by-step explanation:
If high extracellular fluid (ECF) potassium increases potassium conductance, this affects the heart's electrical activity, particularly the repolarization phase. High levels of ECF potassium, known as hyperkalemia, can lead to a partial depolarization of cardiac cells which can impact their ability to properly repolarize. This disturbance in repolarization can, in turn, alter the heart's normal rhythm and the appearance of the electrocardiogram (ECG).
During the cardiac cycle, the T wave on the ECG represents ventricular repolarization. An increase in ECF potassium levels can increase the conductance of potassium ions out of the cardiac cells, thus altering the gradient that drives this ion movement. This could delay repolarization, resulting in a prolonged QT interval. Since the T wave reflects ventricular repolarization, an increase in potassium conductance could also influence the T wave's morphology, potentially leading to a peaked or higher amplitude T wave.
Hyperkalemia can slow down ventricular repolarization and lead to increased T wave height on an ECG, which are both critical factors in assessing cardiac function.