Exercise-induced ST-segment depression in patients without restenosis after coronary angioplasty. Relation to preprocedural impaired left ventricular function.

BACKGROUND ST-segment depression during exercise testing is frequently observed in the absence of restenosis after coronary angioplasty. METHODS AND RESULTS We studied the determinants of this phenomenon in 70 consecutive patients with unstable angina related to a single left anterior descending coronary artery lesion who had successful angioplasty without restenosis (< 50% stenosis by quantitative angiography). We compared preangioplasty clinical, angiographic, and hemodynamic variables in the group with positive (ExT Pos, n = 35; ST depression, 2.3 +/- 0.9 mm) and negative (ExT Neg, n = 35; ST depression, 0.3 +/- 0.5 mm) results on exercise testing at follow-up angiography. At this time, minimal lumen diameter (1.7 +/- 0.4 mm) and mean residual stenosis (34 +/- 11%) in the ExT Pos group were not significantly different from the values (1.9 +/- 0.5 mm, 38 +/- 10%) in the ExT Neg group. Before angioplasty, the ExT Pos group had a lower ejection fraction (63 +/- 8% versus 68 +/- 9%, P < .05), more marked anterior hypokinesis estimated by the extent of anterior wall contraction on quantitative ventriculography (P < .05), and a greater end-systolic volume (30 +/- 11 versus 25 +/- 9 mL/m2, P < .05) than the ExT Neg group. At follow-up angiography, regional anterior wall motion was normal in 68 patients (97%). Anterior hypokinesis before angioplasty was strongly associated (P < .01) with a positive exercise test at control (71% compared with 31% in patients with normal wall motion before angioplasty). CONCLUSIONS In the absence of significant epicardial stenosis after angioplasty, ST-segment depression is strongly associated with the presence of preprocedural regional ventricular dysfunction that has recovered at follow-up angiography.