Specificity and sensitivity of exercise-induced ST segment elevation for detection of residual viability: comparison with fluorodeoxyglucose and positron emission tomography.

OBJECTIVES

We evaluated the sensitivity and specificity of exercise-induced ST segment elevation for the detection of residual myocardial viability.

BACKGROUND

Assessment of residual viability after myocardial infarction is relevant for establishing indication for revascularization. We have previously shown that exercise-induced ST segment elevation is a marker of residual viability.

METHODS

We studied 34 patients with a previous Q wave myocardial infarction (anterior in 21, inferior in 13) of whom 18 (group A) had exercise-induced ST segment elevation in more than one lead (mean [+/- SD] 1.8 +/- 0.9 mm, range 1 to 4) and 16 (group B) did not. All patients underwent rest technetium-99m methoxyisobutyl isonitrile single-photon emission computed tomography (SPECT), fluorine-18 (F-18) fluorodeoxyglucose positron emission tomography and coronary angiography. The time elapsed between the infarction and the viability study was 72 +/- 108 days (range 15 to 400) in group A and 516 +/- 545 days (range 14 to 1,800) in group B.

RESULTS

The presence and site of previous infarction were confirmed by SPECT studies in all 34 patients. Uptake of F-18 fluorodeoxyglucose within the infarcted area was present in 18 of 18 patients in group A but in only 9 (56%) of 16 in group B (p < 0.01). In patients with an anterior infarction, the sensitivity, specificity and predictive accuracy of exercise-induced ST segment elevation for detection of residual viability were 82%, 100% and 86%, respectively (95% confidence intervals 46% to 83.5%, 59% to 100% and 55.6% to 87.1%, respectively).

CONCLUSIONS

Exercise-induced ST segment elevation in infarct-related leads has a high specificity and acceptable sensitivity for detection of residual viability within the infarcted area.