ST segment resolution predicts clinical outcome and response to dobutamine testing after primary percutaneous transluminal coronary angioplasty.
AIM: To assess clinical outcome and improvement in left ventricular (LV) contractility during a six-month follow-up after successful primary percutaneous transluminal coronary angioplasty (PTCA), according to rapid ST segment resolution. The usefulness of early dobutamine echocardiography (DE) in the prediction of LV functional recovery in patients treated with primary PTCA was tested. PATIENTS AND METHODS: One hundred ten consecutive patients with first acute myocardial infarction after successful primary PTCA (Thrombolysis in Myocardial Infarction (TIMI) 3 flow and stenosis of less than 30%) were divided into two groups according to whether ST segment resolution occurred 1 h after the procedure. The patients underwent clinical assessment and echocardiography (ejection fraction [EF] and wall motion index [WMI]) after primary PTCA, during DE on the fourth day of hospitalization, and again after three and six months. RESULTS: In patients with ST segment resolution (n=76 [69.1%]), LVEF increased significantly during the six-month follow-up (P=0.0001). Changes found in the group without ST segment resolution were insignificant (P=0.4). Early DE in patients with rapid ST segment resolution revealed significant improvements in LV contractility measured by EF and WMI. Patients without ST segment resolution had a higher incidence of death (three of 34 [8.8%] versus zero of 76 [0%], P=0.0086), reinfarction (five of 34 [14.7%] versus two of 76 [2.6%], P=0.28) and revascularization (four of 34 [11.8%] versus three of 76 [3.9%], P=0.12). The combined end point (death, reinfarction and revascularization) was significantly lower in patients with ST segment resolution (P=0.03). CONCLUSIONS: Rapid ST segment resolution is associated with LV contractility recovery, and a better clinical outcome and prognosis after successful primary PTCA. Early DE after primary PTCA predicts LV functional recovery. Patients with ST segment resolution are likely to respond to early dobutamine testing.