ST elevation after myocardial infarction: what does it mean?

摘要: Acute coronary syndromes are currently classified according to the presence or absence of ST elevation at hospital admission. usually reflects acute thrombotic occlusion. The most effective treatment consists in recanalisation occluded artery as soon possible, preferably by primary percutaneous intervention (PCI) thrombolytic treatment. However, myocardial salvage relies on rapid, and sustained tissue perfusion. Epicardial patency does not necessarily imply adequate perfusion myocyte level. Alteration endothelial integrity, oedema, platelet aggregation, neutrophil infiltration, distal embolisation thrombus can compromise restoration This low‐reflow no‐reflow phenomenon related microvascular damage be demonstrated several imaging modalities. It was first observed 15 years ago intracoronary contrast echocardiography.1 Myocardial echocardiography, positron emission tomography cardiac magnetic resonance distinguish between obstruction. distinction is clinically important. Indeed, impairment reperfusion leads more extensive necrosis frequent complications, such left ventricular (LV) dysfunction enlargement, in‐hospital decompensation mortality, rehospitalisation for heart failure increased risk death, including sudden death. Numerous studies have tested usefulness ST‐segment recovery an easily obtainable marker clinical outcome. Most concentrated early occurrence resolution versus persistent elevation, comparing 12‐lead ECGs baseline after start On whole, investigations that associated with reperfusion, salvage, smaller infarct area, LV function a lower incidence late complications mortality. These differ their criteria defining resolution: timing treatment, use snapshot ECG continuous monitoring deviation, inclusion reciprocal depression, complete, partial no resolution, method used calculating deviation cut‐off values resolution. Methods analysis accuracy predicting salvage. Patients greater area risk. Early medium‐term mortality accurately estimated simply measuring, 90 minutes thrombolysis, single lead, lead showing maximum deviation. prediction sum resolution.2 Absolute resolution—the score minus reperfusion—better predicts final size than relative resolution—absolute divided baseline.3 Although approach simple, many when depression considered, When population into two groups (presence resolution), value frequently ⩾50% <50% recovery.4 analysed, points applied: ⩾70% complete <70% 30% used, end may time achieve stability resolution.5 Absence indicates failed has been found high whereas small low mortality.6 Partial larger but long‐term risk.7 Early assessment logical used. Absence indicate either reflow epicardial occlusion, which warrant rescue angioplasty pharmacological approaches. After angiographically successful PCI, identifies patients who likely develop damage. information prognostic significance even important if adjunctive therapeutic options shown effective. The predischarge remains useful tool. Several characteristics observed: Q‐wave regression, normalisation persistence negative T waves, QT dispersion. measures analysed rest also assessed during exercise stress test. In this issue journal, Galiuto et al describe functional structural correlates consecutive underwent PCI syndrome (see article page 1376).8 discharge. ⩾0.4 mV. echocardiography performed discharge conventional 6 months. An association anterior infarction, damage, higher wall motion index aneurysm formation. volumes were significantly different groups, exception end‐diastolic volume only discharge, 6‐month follow‐up. Microvascular predictor remodelling Bolognese al,9 study, earliest measurement already made day 1 dilatation defined increase based repeated measurements individual patients. relation surprising. Manes residual infarction independent progressive enlargement.10 Bodi showed had end‐systolic 1 week 6 months.11 Persistent phase considered continuing ischaemia. Later, it pericarditis aneurysm. Aneurysm indeed seen al8 resolved elevation. contrasts other observations relates akinesis dyskinesis septal regions impaired predict aneurysm.12 All infarction.8 Anterior infarcts less collateral flow amount ischaemic stress; explain among compared those inferior infarcts.13 Persistent accompanied waves. Persistent waves—even coexisting elevation—a few months independently worse outcome.14 T‐wave inversions jeopardised myocardium submitted revascularisation. contrast, before stunned improvement function. Later seems viable, revascularised myocardium.15 developing dobutamine testing from rest. often biphasic response stress, sign viable jeopardy recovery.16,17 In summary, although modalities radionuclide techniques provide much precise, costly, information, should classifying syndrome. essential tool stratification identification require aggressive strategies careful follow‐up.