What does the U wave on an EKG represent?

What does the U wave on an EKG represent?

• A. Repolarization of the Purkinje fibers
• B. Activation of the SA node
• C. Contraction of the ventricles
• D. Resting phase of the heart

Answer: (A)

The U wave on an EKG is believed to represent the repolarization of the Purkinje fibers, which are part of the electrical conduction system of the heart. These fibers help ensure that the ventricles contract in a coordinated manner, allowing for efficient pumping of blood. The U wave can sometimes be subtle and may not be present on all EKGs, but when it is observed, it typically follows the T wave, which corresponds to the repolarization of the ventricles themselves. While the other answers reference different aspects of the cardiac cycle, they do not accurately align with what the U wave signifies. For instance, the activation of the SA node pertains to the P wave on the EKG, which indicates atrial depolarization, while ventricular contraction is represented by the QRS complex. The resting phase of the heart is more generalized and does not pertain specifically to the U wave, making the option that identifies it with Purkinje fiber repolarization the correct choice.

The U wave on an EKG is believed to represent the repolarization of the Purkinje fibers, which are part of the electrical conduction system of the heart. These fibers help ensure that the ventricles contract in a coordinated manner, allowing for efficient pumping of blood. The U wave can sometimes be subtle and may not be present on all EKGs, but when it is observed, it typically follows the T wave, which corresponds to the repolarization of the ventricles themselves.

While the other answers reference different aspects of the cardiac cycle, they do not accurately align with what the U wave signifies. For instance, the activation of the SA node pertains to the P wave on the EKG, which indicates atrial depolarization, while ventricular contraction is represented by the QRS complex. The resting phase of the heart is more generalized and does not pertain specifically to the U wave, making the option that identifies it with Purkinje fiber repolarization the correct choice.