ST-elevation myocardial infarction: Difference between revisions
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An '''ST-elevation myocardial infarction''' (STEMI) is a clinical form of [[acute myocardial infarction]] and one form of [[acute coronary syndrome]]. It is defined as the presence of ischaemic symptoms, ST-elevations in a pattern consistent with the blood supply of one coronary artery and a rise and/or fall in [[troponin]] levels. Ischaemic symptoms are classically [[Chest pain|angina]], but may also be dyspnoea, nausea, sweating, anxiety, or non-anginal chest pain. For initial evaluation, see [[acute coronary syndrome]]. | |||
STEMI must be immediately transferred to a [[Percutaneous intervention|PCI]] centre for treatment. | STEMI must be immediately transferred to a [[Percutaneous intervention|PCI]] centre for treatment. | ||
== Diagnosis and evaluation == | == Diagnosis and evaluation == | ||
If a patient has typical chest pain and the ECG shows ST-elevations in a pattern consistent with the blood supply of one coronary artery, we do not waste time with a troponin test, as the probability that it is a STEMI is high. However, in many cases a blood test can be performed in the ambulance, thereby not delaying the time to <abbr>PCI</abbr>. | If a patient has typical chest pain and the ECG shows ST-elevations in a pattern consistent with the blood supply of one coronary artery, we do not waste time with a troponin test, as the probability that it is a STEMI is high. However, in many cases a blood test can be performed in the ambulance, thereby not delaying the time to <abbr>PCI</abbr>. | ||
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ST-elevation or depression in the inferior leads (II, III, aVF) suggests inferior wall infarct. In these cases, the right-sided leads V4R, V5R, and V6R should be obtained to assess for a possible right ventricular infarct. In this case, ST-elevation would be present in leads V4R – V6R. | ST-elevation or depression in the inferior leads (II, III, aVF) suggests inferior wall infarct. In these cases, the right-sided leads V4R, V5R, and V6R should be obtained to assess for a possible right ventricular infarct. In this case, ST-elevation would be present in leads V4R – V6R. | ||
ST-elevations can be present in other conditions which may present similarly, like [[pericarditis]], [[myocarditis]], [[left ventricular hypertrophy]], etc. Care must be used in ambiguous cases, but it’s often better to perform a PCI to be safe. | ST-elevations can be present in other conditions which may present similarly, like [[pericarditis]], [[myocarditis]], [[left ventricular hypertrophy]], etc. Care must be used in ambiguous cases, but it’s often better to perform a PCI to be safe. | ||
== Pathomechanism == | == Pathomechanism == | ||
See [[acute myocardial infarction]]. | See [[acute myocardial infarction]]. | ||
== Initial management == | == Initial management == | ||
If the expected time to a PCI lab is < 120 minutes, the patient is rushed straight there, with as low time from symptom onset to catheter insertion as possible. If the expected time is > 120 minutes, the patient should receive [[thrombolysis]] and then be rushed to a PCI lab. | If the expected time to a PCI lab is < 120 minutes, the patient is rushed straight there, with as low time from symptom onset to catheter insertion as possible. If the expected time is > 120 minutes, the patient should receive [[thrombolysis]] and then be rushed to a PCI lab. | ||
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[[Nitroglycerine]], either sublingual tablets or sprays, should only be given if the patient has pain. It may be administered to the patient up to three times but does not improve outcome and is therefore not given routinely to all. Nitroglycerine is contraindicated in right ventricular infarction and should therefore not be administered if right ventricular infarction is suspected. | [[Nitroglycerine]], either sublingual tablets or sprays, should only be given if the patient has pain. It may be administered to the patient up to three times but does not improve outcome and is therefore not given routinely to all. Nitroglycerine is contraindicated in right ventricular infarction and should therefore not be administered if right ventricular infarction is suspected. | ||
[[Aspirin]] (300 mg) should be administered to all patients to be chewed and swallowed in all cases of STEMI. In addition to this, a loading dose of a [[P2Y12 inhibitor]] like prasugrel or ticagrelor may be administered. | |||
[[Beta blocker|Beta blocker,]] most often metoprolol, should be administered in all cases where the patient does not have signs of heart failure and is haemodynamically stable. | [[Beta blocker|Beta blocker,]] most often metoprolol, should be administered in all cases where the patient does not have signs of heart failure and is haemodynamically stable. | ||
[[Atorvastatin]] (80 mg) should be administered to all patients as soon as possible. | |||
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If the anatomy is unsuitable for PCI and the infarcted myocardial area is large, or there is cardiogenic shock, emergency [[coronary artery bypass surgery]] (<abbr>CABG</abbr>) should be performed. | [[Unfractionated heparin]] (<abbr>UFH</abbr>) is administered to all patients unless they’re already anticoagulated. | ||
If the anatomy is unsuitable for PCI and the infarcted myocardial area is large, or there is cardiogenic shock, emergency [[coronary artery bypass surgery]] (<abbr>CABG</abbr>) should be performed. | |||
Summary: | Summary: | ||
* Aspirin (300 mg loading dose) – in all cases | * Aspirin (300 mg loading dose) – in all cases | ||
* P2Y12 inhibitor loading dose ( | * P2Y12 inhibitor loading dose (prasugrel or ticagrelor) – in all cases | ||
* Atorvastatin – in all cases | * Atorvastatin – in all cases | ||
* Unfractionated heparin – in all cases except with pre-existing anticoagulation | * Unfractionated heparin – in all cases except with pre-existing anticoagulation | ||