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Table 1: Most common conditions associated with changes in the U wave. |
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Negative U waves |
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Cardiac disease • Coronary artery disease • Hypertension • Valvular disease • Primary cardiomyopathy • Left ventricular enlargement • Congenital heart disease |
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Other conditions • Hyperthyroidism |
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Normal • 7% of the population has negative U waves without heart disease |
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Prominent U waves |
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Rhythms • Bradycardia • Complete heart block • Congenital long QT syndrome |
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Cardiac disease • Early repolarization • Mitral valve prolapse • Left ventricular enlargement • Cardiomyopathy • Circumflex-related myocardial infarction |
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Physical • Hypothermia • Forced inspiration • After exercise • Central nervous system/cerebral events |
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Electrolytes • Hypokalemia • Hypomagnesemia • Hypocalcemia |
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Medications • Class III antiarrhythmics • Class IA antiarrhythmics • Epinephrine • Digitalis • Phenothiazines |