Relationship of myocardial ischemia and injury to coronary artery disease in patients with supraventricular tachycardia.

Increase of serum troponin I and ST-segment depression are objective markers of myocardial ischemia/injury. Abnormalities of the 2 indicators have been associated with supraventricular tachycardia (SVT) but their relevance for diagnosing acute coronary syndrome and the presence of coronary artery disease (CAD) in this setting have not been clarified. Therefore, we sought to evaluate the frequency of CAD based on increased troponin I and ST-segment depression during SVT. During a 5-year period, 104 patients were admitted with a diagnosis of SVT, 80 of whom had troponin I testing, and 70 of these patients could be assessed for ST-segment changes. Thirty-seven patients (48%) had increased troponin I (mean 1.54 +/- 2.7 ng/dl, normal <or=0.07 ng/dl) and 46 patients (57%) had ST-segment depression >or=1.0 mm. There were no significant differences in baseline characteristics and clinical presentation of patients with and without troponin I increase or ST-segment depression. There was no difference in the diagnosis of CAD by noninvasive or invasive testing in patients with and without increased troponin I. More patients with than without ST-segment depression had evidence of CAD (22% vs none, p = 0.01), but after adjusting for covariates, ST-segment depression was not a significant predictor of CAD. In conclusion, increased troponin I and ST-segment depression are not significant markers of acute coronary syndrome in patients with SVT.