What causes large U waves on ECG?

A relatively frequent cause for a large U-wave is hypokalaemia. It is observed in patients with bradycardia, ventricular hypertrophy, hypothyroidism, hypocalcaemia, hypomagnesaemia, mitral valve prolapse, hypothermia, increased intracranial pressure, or patients on anti-arrhythmic medicine.

Where is the U wave on ECG?

U waves are usually best seen in the right precordial leads especially V2 and V3. The normal U wave is asymmetric with the ascending limb moving more rapidly than the descending limb (just the opposite of the normal T wave).

Why does hypokalemia cause aU wave?

Hypokalemia increases diastolic depolarization of Purkinje fibers, thereby increasing automaticity and underlying the basis of U waves. All of these molecular changes contribute to a reduction in repolarization reserve.

What causes the U wave?

The ‘U’ wave is a wave on an electrocardiogram (ECG). It comes after the T wave of ventricular repolarization and may not always be observed as a result of its small size. ‘U’ waves are thought to represent repolarization of the Purkinje fibers.

What does the U wave do?

In the electrocardiogram (ECG) the U wave is the deflection that follows the waves of depolarization (QRS) and repolarization (T) of the heart chambers. Its polarity is normally the same as that of the T wave.

What do u waves indicate?

Are U waves normal?

The normal U wave is best seen at rest in the precordial leads and is more commonly seen during sinus bradycardia. Studies evaluating the response of the QT interval to tachycardia (produced by exercise or atrial pacing) in healthy individuals have often ignored the U waves.

What causes U wave?

What is hypokalemia in ECG?

Hypokalemia results in slowed conduction, delayed ventricular repolarization, shortened refractory period and increased automaticity. 3. ECG changes include flattening and inversion of T waves in mild hypokalemia, followed by Q-T interval prolongation, visible U wave and mild ST depression4 in more severe hypokalemia.