DOBUTAMINE-ATROPINE STRESS ECHOCARDIOGRAPHY FOR REVERSIBLE DYSFUNCTION DURING THE FIRST WEEK AFTER ACUTE MYOCARDIAL-INFARCTION - LIMITATIONS AND DETERMINANTS OF ACCURACY

Objectives. We sought to compare the accuracy of biphasic and ischemic responses and sustained improvement for reversible dysfunction and to identify causes of false negative and false positive findings. Backgr ound. Previous studies have shown that low dose dobutamine echocardiog raphy was accurate for detecting reversible dysfunction after acute my ocardial infarction (MI) but did not determine whether accuracy was im proved by peak dose findings or influenced by the test interval or cli nical or angiographic factors. Methods. Dobutamine-atropine stress ech ocardiography (DASE) (baseline, low dose [5 and 10 pg/kg body weight p er min] and peak dose) and coronary angiography were performed in 115 patients 2 to 7 days after MI (test interval). Segmental wall thickeni ng was analyzed according to the 16-segment model. Sustained improveme nt and biphasic and ischemic responses included improved wall thickeni ng at low and peak doses, improved wall thickening at the low dose wit h worsening at peak dose and no change in wall thickening at the low d ose with worsening at peak dose, respectively. Follow-up echocardiogra phy was performed at 4 to 8 weeks, and reversible dysfunction was defi ned as improved wall thickening. Results. Wall thickening improved at follow-up in 305 (44%) of 688 dysfunctional segments. The test interva l was 2 days in 16 patients, 3 days in 24, 4 days in 24, 5 days in 12, 6 days in 16 and 7 days in 23. No change at low and peak doses accura tely predicted fixed dysfunction (318 [88%] of 360 segments), especial ly in akinetic and dyskinetic segments (276 [91%] of 303), irrespectiv e of the test interval or clinical and angiographic factors. Ischemic segmental responses also predicted fixed dysfunction (63% [12 of 19 pa tients]), especially in medically treated compared with revascularized patients (100% [8 of 8] vs. 36% [4 of 11], p = 0.013), Both biphasic responses and sustained improvement (77% [179 of 231 segments] vs. 87% [84 of 97], p = 0.082) were highly predictive of reversible dysfuncti on, especially in akinetic segments, irrespective of the test interval or clinical and angiographic factors. The only limitation was reduced accuracy (77% [177 of 222 segments], p < 0.001) due to false positive results (16%) in hypokinetic segments. Conclusions. No change and isc hemic responses during DASE were specific for fixed dysfunction. Impro ved wall thickening at the low dose, irrespective of changes at peak d ose, was highly predictive of reversible dysfunction. Accuracy was onl y limited by false positive results in hypokinetic segments and not by the test interval or clinical or angiographic factors. (C) 1997 by th e American College of Cardiology.