As a cardiac electrophysiologist, I specialize in the study of the electrical activity of the heart. When it comes to the 'U' wave on an electrocardiogram (ECG), it is a distinct feature that follows the 'T' wave and precedes the P wave in the cardiac cycle. Here's a detailed explanation: The 'U' wave is a wave on an electrocardiogram (ECG) that is often overshadowed by the more prominent P, QRS, and T waves. It is the smallest of the ECG deflections and represents a late phase of ventricular repolarization. The 'U' wave is not always visible because of its small amplitude, and its presence can be influenced by various factors such as heart rate, electrolyte imbalances, and the use of certain medications. The exact mechanism of the 'U' wave is not completely understood, but it is generally believed to be due to the repolarization of the Purkinje fibers, which are a part of the cardiac conduction system that helps to synchronize the contraction of the ventricles. This repolarization occurs after the ventricular muscle cells have repolarized, which is represented by the T wave. 'U' waves can also be more pronounced under certain conditions. For example, they may become more visible with slower heart rates, as the interval between the T wave and the P wave increases, allowing the 'U' wave to be seen more clearly. Additionally, 'U' waves can be accentuated in the presence of hypokalemia (low potassium levels) or after the administration of certain drugs that affect the cardiac action potential. In summary, the 'U' wave is a small, late repolarization wave on the ECG that is not always easily observed. It is thought to represent the repolarization of the Purkinje fibers and can be influenced by various physiological and pharmacological factors. read more >>

The 'U' wave is a wave on an electrocardiogram (ECG). It is the successor of the 'T' wave and may not always be observed as a result of its small size. 'U' waves are thought to represent repolarization of the Purkinje fibers.read more >>