Curious Consequences of the Lessor Metals

The vagaries of any list or group are that invariably some members are far more popular than others. Hyperkalemia gets all of the attention when we talk about the cardiac effects of electrolyte abnormalities. It is certainly important (read: life-threatening), and we have multiple life-saving treatments that lend themselves well to testing.   We are well versed in hyperkalemia, though one of its treatments has become controversial (I am looking at you, kayexalate). But other electrolyte abnormalities beyond hyperkalemia also deserve attention.   Hypokalemia: The potassium level in the body is closely regulated, but hypokalemia can still develop by several mechanisms, including gastrointestinal loss, renal potassium wasting, or shifting potassium into the intracellular space with an alkalosis. Characteristic changes in the ECG are associated with hypokalemia, which become more prominent as the hypokalemia worsens. The T waves flatten, and may disappear. A U wave may develop, seen as a small deflection after the T wave and in the same direction. Its magnitude is usually <0.5 mm, but it is inversely proportional to the pulse, becoming larger at a slower heart rate. It is most prominent in V2 and V3. It is important not to mistake the QU interval for a prolonged QT interval.     ECG of patient with hypokalemia and hypomagnesemia.   The myocardium is very sensitive to hypokalemia, with its largest effect on inhibiting the action of the delayed rectifier potassium channels ...
Source: Spontaneous Circulation - Category: Emergency Medicine Tags: Blog Posts Source Type: blogs