Patient Care Technician (PCT) AAH Practice Exam

Which small wave is sometimes observed between the T wave and P wave in an ECG?

1. P wave

2. QRS wave

3. U wave

4. R wave

The correct answer is: U wave

The U wave is considered the small wave that may sometimes be seen following the T wave and preceding the P wave in an electrocardiogram (ECG) reading. The U wave is generally thought to represent the repolarization of the Purkinje fibers, which are part of the heart's conduction system. While it is usually not prominent, it's occasionally visible in healthy individuals, particularly in cases of bradycardia, hypokalemia, or high vagal tone. Understanding the significance of the U wave can be important in clinical settings, as changes in its appearance can provide valuable insights into a patient’s cardiac health, potentially indicating underlying issues like electrolyte imbalances or slowed ventricular repolarization. This context is particularly relevant when monitoring patients and interpreting their ECGs. In contrast, the P wave denotes atrial depolarization, the QRS wave signifies ventricular depolarization, and the R wave specifically represents a portion of the QRS complex. These waves each represent different electrical activities of the heart and do not fit the description of a small wave that occurs between the T and P waves, highlighting the distinct role of the U wave in the overall cardiac cycle.