Significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and an open infarct-related artery Analysis with angiography, intracoronary myocardial contrast echocardiography and cardiac magnetic resonance.

ABSTRACT

AIMS: The significance of exercise-induced ST segment elevation in Q leads in patients with a recent myocardial infarction and without significant residual stenosis in the infarct-related artery has not been defined. We aimed to elucidate the role of myocardial perfusion and viability in this scenario. METHODS AND RESULTS: Sixty-six patients with a first myocardial infarction, single-vessel disease and an open artery were studied. Myocardial perfusion was assessed with angiographic blush, intracoronary myocardial contrast echocardiography and magnetic resonance. Myocardial viability was quantified by means of magnetic resonance (transmural extent of necrosis). Exercise-induced ST elevation in Q leads was observed only in 13 cases (20%); 53 patients (80%) did not show this finding. The group with ST elevation had fewer cases with normal perfusion Blush 3 (15% vs. 74%, p=0.001), myocardial contrast echocardiography score >0.75 (8% vs. 81%, p=0.001) and magnetic resonance score >0.75 (31% vs. 68%, p=0.03). Similarly, myocardial viability (necrosis <50%) was less frequent in patients with ST elevation (8% vs. 72%, p=0.001). CONCLUSION: In patients with a first myocardial infarction and without residual ischemia, exercise-induced ST segment elevation in Q leads is an uncommon finding and it is related to a more damaged coronary microcirculation and to less viable myocardium.