False-Positive ST-T-Wave Changes Secondary to Hyperventilation and Exercise

Eleven patients had "positive" ST-segment depression, with exercise testing and with forced hyperventilation at rest. None of the five patients who had coronary arteriograms had evidence of coronary artery disease, and the clinical impression was that the other six patients did not have coronary artery disease. Four patients had mitral valve abnormalities, shown by the left ventricular angiographic findings of mitral valve prolapse or auscultatory evidence of the systolic click-late systolic murmur syndrome. None of the 17 control patients who had positive exercise tests and positive coronary arteriograms had positive hyperventilation studies at rest. Coronary artery disease does not seem to cause the ST-segment changes in these 11 patients; their cause is still unknown.