QT interval is shoened in-
High-Yield Explanation
only in hypercalcemia QT interval is shoened in the other 3 QT interval is prolonged Hypercalcemia: The most common ECG findings of hypercalcemia are a sho QT interval secondary to a shoened ST segment. There may also be a widened or flattened T wave; however, significant hypercalcemia can cause ECG changes that mimic an acute myocardial infarction. Ref Harrison 20th edition pg 1556