C. Acute myocardial infarction. D. First-degree atrioventricular block. This is usually a progressive pattern. 1 Hypokalemia, although tolerated well in most patients, can be life-threatening in those with underlying cardiac disease. Treatment includes potassium replacement and correction of the underlying cause when possible.
Some patients require daily potassium supplementation.
Interestingly, the hypokalemia occurring in this patient was a result of Bartter's syndrome, a rare hereditary disorder of renal potassium wasting secondary to impaired electrolyte transport in the ascending loop of Henle. It is treated mainly by liberal potassium supplementation. As for the remaining multiple-choice answers, hypocalcemia manifests itself on ECG as a prolonged QT interval, which is not present in this tracing. There are no ST elevations or other changes suggestive of acute myocardial infarction in this tracing. First-degree atrioventricular block should also be ruled out because the PR interval on the ECG shown here is less than 0.20 mm.