Patterns of acute inferior wall myocardial infarction caused by hyperkalemia.

This is one of the first published articles dealing with two patients with hyperkalemia showing, not only a pattern of acute anteroseptal myocardial infarction, but of inferior myocardial infarction as well. This was attributed to uneven effects of high potassium in different regions of the heart. Marked reduction of resting potential of a large group of cells from the most affected regions could produce areas of inexcitability, capable of generating abnormal q waves. Likewise, ST-segment elevation could be attributed to a hyperkalemic diastolic current of injury (due to depolarization of resting potential) and to a combination of diastolic and systolic current of injury (due to a reduction of action potential amplitude). In addition, current flowing down voltage gradients on either side (epicardial and endocardial) of the M cell region could be responsible for the T wave, and even, to some extent, to the ST-segment changes. However, it cannot be excluded that the previously described changes may have resulted from coronary spasm without chest pain. In fact, an intriguing possibility, namely that hyperkalemia could trigger coronary spasm has to be considered also.