The nurse observes the following EKG. Which tab would the nurse correlate with this finding?

A. Na+ 134: A sodium level of 134 mEq/L represents mild hyponatremia, which can cause neurologic symptoms such as confusion or seizures but does not typically produce U-waves on an EKG. Sodium imbalances mainly affect neuronal and fluid balance rather than cardiac repolarization patterns seen on ECG. B. Mg+ 1.8: A magnesium level of 1.8 mg/dL is within the normal range (1.7–2.2 mg/dL). Magnesium disturbances can influence cardiac conduction and increase the risk of arrhythmias, but normal magnesium would not explain prominent U-waves. C. K+ 6.1: Hyperkalemia can cause peaked T-waves, widened QRS complexes, and flattened P-waves, but it does not produce prominent U-waves. Therefore, a potassium level of 6.1 mEq/L is inconsistent with the observed U-waves. D. K+ 2.1: Hypokalemia is strongly associated with the appearance of U-waves on the EKG, as low potassium prolongs repolarization of the ventricular myocardium. A potassium level of 2.1 mEq/L is critically low and explains the extra waves following the T-wave, making it the correct correlation with this EKG finding.