https://ecgvn.com/en/tags/u-wave/ Recent content in U Wave on ECG Library – LITFL Basics Hugo en-us Tue, 08 Oct 2024 00:00:00 +0000 https://ecgvn.com/en/posts/u-wave/ Tue, 08 Oct 2024 00:00:00 +0000 https://ecgvn.com/en/posts/u-wave/ <h4 id="u-wave-overview">U wave Overview</h4> <p>The U wave is a small (0.5 mm) deflection immediately following the T wave</p> <ul> <li>U wave is usually in the same direction as the T wave.</li> <li>U wave is best seen in leads V2 and V3.</li> </ul> <p><a href="https://litfl.com/wp-content/uploads/2018/10/ECG-waves-segments-and-intervals-LITFL-ECG-library-3.jpg"><img alt="ECG basics: waves, segments and intervals LITFL ECG library" loading="lazy" src="https://litfl.com/wp-content/uploads/2018/10/ECG-waves-segments-and-intervals-LITFL-ECG-library-3.jpg"></a></p> <h4 id="source-of-the-u-wave">Source of the U wave</h4> <p>The source of the U wave is unknown. Three common theories regarding its origin are:</p> <ul> <li>Delayed repolarisation of Purkinje fibres</li> <li>Prolonged repolarisation of mid-myocardial “M-cells”</li> <li>After-potentials resulting from mechanical forces in the ventricular wall</li> </ul> <hr> <h4 id="features-of-normal-u-waves">Features of Normal U waves</h4> <ul> <li>The U wave normally goes in the same direction as the T wave</li> <li>U -wave size is inversely proportional to heart rate: the U wave grows bigger as the heart rate slows down</li> <li>U waves generally become visible when the heart rate falls below 65 bpm</li> <li>The voltage of the U wave is normally &lt; 25% of the T-wave voltage: disproportionally large U waves are abnormal</li> <li>Maximum normal amplitude of the U wave is 1-2 mm</li> </ul> <p><a href="https://litfl.com/wp-content/uploads/2018/08/Normal-U-Wave.jpg"><img alt="Normal U Wave" loading="lazy" src="https://litfl.com/wp-content/uploads/2018/08/Normal-U-Wave.jpg"><img alt="Normal U Wave" loading="lazy" src="https://litfl.com/wp-content/uploads/2018/08/Normal-U-Wave.jpg"></a></p>