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a positive wave following an upright T wave of the electrocardiogram. It is negative following an inverted T wave.
U waveCardiology An EKG wave that follows the T wave; it is upright and has 5% to 50% of the T wave amplitude; it is most prominent in V2 and V3, where it may reach 0.2 mV; the genesis of the U wave is uncertain, but has been attributed to either Purkinje fiber repolarization or to ventricular relaxation; the U wave fuses with the T wave in the face of ↓ ventricular filling and ejection, or when the Q-T interval is prolonged as in hypocalcemia or with quinidine therapy; the U wave is exaggerated in hypokalemia, digitalis therapy or with some antiarrhythmics; inverted in 1% of the normal population, or in Pts with HTN, aortic or mitral valve disease, right ventricular hypertrophy, and myocardial ischemia
Waveform in an electroencephalographic tracing sometimes following the T wave and representing the completion of ventricular repolarization.