• Acute coronary syndrome (ACS) results from a local reduction or cessation of blood flow in a coronary artery. This is most often caused by a sudden thrombus formation associated with rupture or erosion of an atherosclerotic plaque in the coronary artery wall.
  • In the absence of an acute atherothrombotic coronary stenosis, imbalance between the myocardial oxygen need and the availability of oxygen, and consequently myocardial ischaemia, may also be caused by conditions such as tachycardia or bradycardia, coronary spasm, hypotension, anaemia, respiratory insufficiency or other severe disease, such as sepsis.
• Classification of ACS
  • Unstable angina (pectoris, UAP)
  • Non ST elevation myocardial infarction (NSTEMI)
  • ST elevation myocardial infarction (STEMI)

• When ACS is suspected, the working diagnoses are STEMI, NSTEMI, UAP, other symptom of cardiac origin or other chest pain.
• The diagnosis of ACS is based on the symptoms, troponin testing and ECG findings. The diagnosis is confirmed if the concentration of cardiac biomarkers is increased. For non-ischaemic causes of chest pain, see table T1.
• Acute myocardial ischaemia typically causes chest pain. The pain starts abruptly, is often severe, crushing, heavy or "band-like” in nature and not greatly influenced by breathing or changing position.
  • Pain suggestive of myocardial infarction is prolonged, persisting for over 20 minutes, and usually of constant intensity.
  • It is widespread in the retrosternal area, possibly radiating to the upper arms (usually to the left arm), back, neck or the jaw.
  • In some patients the painbegins in the upper abdomen accompanied by nausea.
  • For symptoms associated with the probability of acute coronary syndrome, see table T2.
• Especially in elderly patients (> 75 years of age) and patients with diabetes, chronic heart failure, renal failure or dementia, the leading symptoms of ACS may consist of a feeling of nausea, suddenly impaired general condition, confusion, heaviness as well as sweating.
• Particularly in inferior wall damage, severe vagotonia may induce bradycardia and hypotension which will manifest as dizziness or fainting.
• Other clinical manifestations of ACS include acute pulmonary oedema, loss of consciousness and sudden death.

ECG

• ECG must be recorded and examined immediately if ACS is suspected.
• 15–16 leads should be recorded routinely for every patient.
  • Additional leads: V4R (right ventricle), V7–V9 (posterior wall)
  • Contiguous leads: lateral leads I, aVL, V6; inferior leads II, III, aVF; anterior leads V4–V6; posterior leads V7–V9
• Serial ECG recordings (every 15–30 minutes) may be useful if the pain continues or recurs..
• In the initial phase, it is advisable to leave the chest leads in place or mark their position on the skin to ensure the comparability of the subsequent recordings.
• A Q wave in an ECG will increase the likelihood of coronary heart disease (CHD). See table T3 for the criteria for prior Q wave myocardial infarction (MI).
• Differential diagnosis of ECG changes, see table T4.

ECG diagnosis: UAP and non ST elevation myocardial infarction (NSTEMI)

• New ST depression of > 0.5 mm in two contiguous leads, even transient, is suggestive of myocardial ischaemia in a patient with chest pain.
• The deeper and more widespread the ST depressions are, the more extensive ischaemia and worse prognosis they suggest.
• T wave inversion (> 1 mm) in two contiguous leads with R/S ratio > 1.
• Deeply inverted T waves (> 2 mm)
• A normal ECG recording does not exclude acute myocardial ischaemia.

ECG diagnosis: ST elevation myocardial infarction

• A new ST elevation of ≥ 2.5 mm in men below 40 years of age, of ≥ 2 mm in men at least 40 years of age, and of ≥ 1.5 mm in women in at least two anatomically contiguous leads V2–V3, and/or ST elevation of ≥ 1 mm in at least two other anatomically contiguous leads, provided that there are no LBBB or LVH changes or other abnormalities of the ST segment in the ECG, or ventricular pacing
• ST elevation of > 0.5 mm in leads V7–V9 (posterior wall) and reciprocal ST depression of > 0.5 mm in leads V1, V2, V3, R/S ratio > 1 in leads V1–V2
• In inferior infarction, leads V3R–V4R are recorded in order to determine infarction changes in the right ventricle.
• A bundle branch block (LBBB) that is, or is suspected of being, new, with acute chest pain, does not necessarily indicate acute obstruction of the coronary artery. The decision on urgency of treatment must be based on the clinical picture.
• Comparison with an earlier ECG is important.

Special remarks

• If the patient is known to have LBBB, new ST elevation of > 1 mm parallel to the QRS complex or new ST depression of > 1 mm parallel to the QRS complex in leads V1, V2 or V3 may be suggestive of a new ischaemic event.
• ST elevation in leads aVR and V1 together with ST depression in leads V4–V6 is suggestive of obstruction of the left main coronary artery branch or of severe CHD (so-called global ischaemia).
• If the patient has a ventricular-paced rhythm, comparison with earlier ECG recordings may reveal a new ST elevation; see LBBB (Bundle branch blocks in an ECG).

Cardiac biomarkers

• Myocardial ischaemia causes tissue damage and myocardial cell death with the consequent release of measurable cardiac biomarkers into the circulation. Troponins (TnT and TnI) are the primary markers in use; creatine kinase isoenzyme MB mass (CK-MBm) is used in special cases.
• When the high-sensitivity troponin assay is in use, concentrations exceeding the upper reference range threshold can be measured in almost all patients with myocardial infarction 3 hours after the onset of symptoms already. The reference range applied in the local unit must be taken into account.
• The improved sensitivity of cardiac biomarkers has increased the number of NSTEMI diagnoses and, respectively, reduced the number of UAP diagnoses. The negative predictive value of sensitive troponin is excellent, and it excludes, in practice, the possibility of a myocardial infarction.
• Increased troponin concentrations may be present in other conditions that are associated with myocardial damage without myocardial infarction. These include myocarditis, heart failure, cardiomyopathy, sequela of a tachyarrhythmic episode, severe anaemia and shock. The concentration may also increase in pulmonary embolism, sepsis, renal failure, cerebral infarction and subarachnoid haemorrhage.
• An increase in an already elevated troponin concentration (renal failure, fresh myocardial infarction) may also be diagnostic in recurrent myocardial infarction (an increase of more than 20%). In such a case, CK-MBm measurement can also be used.
• The increased troponin concentration decreases gradually, and slightly increased concentrations may still be detected after a period of 2 weeks.

Other investigations

• A chest x-ray should be taken in the hospital to aid the haemodynamic assessment.
• Echocardiography should be performed as soon as possible, in order to evaluate the myocardial function.
  • Echography can also be used for differential diagnosis.

• The patient should be given bed rest. Aspirin 250 mg to chew and swallow or 150 mg intravenously, unless the patient is allergic to aspirin. The initial dose should be followed by continuous treatment with aspirin 100 mg/day, unless contraindicated.
• Fast-acting nitrate spray to relieve chest pain, may be repeated twice at intervals of 5 minutes if necessary, provided that systolic blood pressure is over 100–110 mmHg.
• Supplemental oxygen if hypoxia is detected (SpO₂ < 90%) in continuous oxygen saturation monitoring. Oxygen saturation target is > 94–98%, in severe COPD 88–90%.
  • Oxygen therapy is not recommended if blood oxygen saturation is ≥ 90%.
• Monitoring should be started (ECG, blood pressure, SpO₂) and an intravenous line placed.
• For persistent chest pain, an initial dose of morphine 4–8 mg followed by repeated intravenous bolus doses of 2–4 mg.
• If reassurance is not sufficient to calm the patient, intravenous diazepam 2.5–5 mg may be given.
• A nitrate infusion if chest pain continues (after 1–2 doses of nitrate spray), blood pressure is elevated or there are signs of heart failure. The patient must not be hypotensive (systolic BP should be > 100 mmHg) or hypovolaemic nor exhibit signs of right ventricular infarction.
• Ondansetron 4 mg or droperidol (DHBP) 1.25 mg i.v. for nausea
• If tachycardia, arrhythmias or hypertension occur, a beta blocker (metoprolol 2–5 mg i.v.; be careful if the patient has hypotension, hypovolaemia or heart failure).

• The risk of death and further cardiac events in patients with myocardial infarction is greatest during the first few days after the acute event, and the risk will remain increased, at least during the first month. The risk of short-term adverse outcomes must therefore be assessed (history, physical examination and ECG) without delay in all patients who are suspected to have cardiac chest pain. The more the high-risk criteria are met, the greater the likelihood of a cardiac event.
• The treatment should be started right after the diagnosis is confirmed, without waiting for the troponin results. The treatment is aimed at stabilizing the accelerated thrombotic process in the coronary artery and the hemodynamic status.
• The treatment should be carried out in a coronary care unit or another ward with facilities to continuously monitor the patient´s haemodynamic state and symptoms of ischaemia.

Antithrombotic therapy

• A decision on starting the administration of an ADP receptor inhibitor (ticagrelor, clopidogrel, prasugrel) should be made only after contrast-enhanced imaging. The drug should be chosen according to the local guidelines and to the clinical assessment of the patient.
  • Initial loading doses:
    • ticagrelor 180 mg (continued with 90 mg twice daily)
    • clopidogrel 600 mg (continued with 75 mg/day)
    • prasugrel 60 mg (continued with 10 mg once daily)
  • The effect of clopidogrel has a slower onset, and in some patients (about 20 %) its anti-platelet effect may remain inadequate.
  • If contrast-enhanced imaging cannot be arranged within 24 hours, starting an ADP receptor inhibitor already before such imaging should be considered.
• Low molecular weight heparin [Evidence Level: A]: enoxaparin 1 mg/kg twice daily s.c.; the dose should be reduced in patients over 75 years (–25%) and in renal failure (GFR < 30 ml/min, –50%).
• Thrombolysis is of no benefit.
• If the patient is being treated with an anticoagulant
  • Warfarin therapy with INR in the therapeutic range (2.0–3.0) should be continued without interruption instead of heparin treatment. If INR is below the therapeutic range, anticoagulation with warfarin can be continued at discretion together with a reduced dose of heparin until the target INR level has been reached, or with heparin only. If INR is too high, warfarin should be paused. The action of warfarin can be reversed by administering Vitamin K1 (phytomenadione, Konakion^®) 1–3 mg intravenously, even though there is only limited evidence of its benefit. Treatment with warfarin may then be continued. INR should be determined daily, if warfarin is continued.
  • If the patient is using a direct oral anticoagulant (dabigatran, rivaroxaban, apixaban, edoxaban), it need not normally be paused.. Local guidelines should be followed and a cardiologist performing invasive prodecures consulted.
  • Start aspirin and, after contrast-enhanced imaging, clopidogrel, as necessary, for patients on anticoagulants. Use of ticagrelor and prasugrel should be avoided.
• Always remember to assess the risk of thrombosis (CHA₂DS₂-VASc) and bleeding (HAS-BLED) (see tables in (Indications for and implementation of anticoagulant therapy in atrial fibrillation)). Factors increasing the risk of bleeding include anaemia, thrombocytopenia, age > 75 years, renal failure, liver failure, female gender, weight < 65 kg, systolic BP >160 mmHg, a previous history of a bleeding tendency and medications affecting the platelet function.

Anti-ischaemic and other treatment

• A nitrate infusion if the chest pain persists, blood pressure is elevated or there are signs of heart failure. The patient must not be hypotensive (systolic BP should be > 100–110 mmHg) or hypovolaemic nor exhibit signs of right ventricular infarction. Nitrate infusion is more effective than the drug administered orally.
  • The initial dose is 13–20 µg/min = 8–12 ml/hour when the concentration is 100 µg/ml. If necessary, the dose may be increased every few minutes up to 120 ml/h whilst closely monitoring blood pressure.
• A beta blocker (metoprolol) intravenously as 2.5–5 mg bolus doses if blood pressure is elevated or tachycardia or arrhythmias occur (be careful if the patient has hypotension < 120 mmHg or heart failure). A beta blocker already in use should be continued, provided that there is no hypotension or cardiac failure.
  • Starting an oral beta blocker should be considered within the first 24 hours, after haemodynamic stabilization, if the patient has heart failure or left ventricular dysfunction and if there are no contraindications for the drug.
• An ACE inhibitor should be started within the first 24 hours of treatment in patients with heart failure, systolic left ventricular dysfunction, anterior wall infarction or diabetes. Low blood pressure (systolic BP < 100 mmHg) should be avoided; exercise caution if the patient has renal failure.
• Early introduction of a statin, i.e. during the first day of treatment, at a high therapeutic dose is recommended.
• NSAIDs should be stopped and should not be used for pain relief.
• A PPI should be considered when an anticoagulant and/or aspirin and/or an ADP receptor inhibitor is in use. The risk of GI bleeding is also increased by a history of GI bleeding, continuous glucocorticoid or NSAID medication, age > 65 years, dyspepsia, reflux disease and excessive use of alcohol.

Invasive treatment, revascularization (PTCA and CABG)

• Urgent invasive assessment and treatment without delay
  • If the patient is in cardiogenic shock, if he/she has chest pains despite treatment, or if the haemodynamic state is regarded as unstable (arrhythmias, hypotension, heart failure).
• Early invasive assessment and treatment 24–72 h
  • Individual risk assessment and timing of the invasive investigation according to its results (e.g. < 24 hours or < 72 hours); see table T5
  • Signs of increased risk (recurrent ST–T fluctuations, high release of cardiac biomarkers, heart failure, earlier PCI/CABG, diabetes, renal failure) have an influence on the more specific timing of the investigation.
• In most cases only the occluded infarct-related artery is treated, and other possible stenoses are treated at a later date.

• STEMI may be, more often in men than in women, the first presentation of CHD without preceding angina pain. The patient may therefore not necessarily be able to interpret the symptoms as originating from the heart, which results in an unnecessary delay before the first medical contact is made.
• It is of the utmost importance that primary care providers are able to recognise the symptoms since STEMI is associated with a high risk of life-threatening arrhythmias, conduction defects, sudden death and heart failure. Integrated care pathways incorporating local guidelines implemented in all health care facilities providing on-call services facilitate the easy identification and management of STEMI patients.
• A diagnosis should be made and the patient treated as quickly as possible, and an ECG must be recorded as soon as the first medical contact is made. Serial ECGs should be recorded frequently if no changes are noted but the symptoms are suggestive of an MI.

Initial management

• See above .
• If the ST elevation is corrected with nitrate, the underlying condition may be a coronary artery spasm either with or without an acute myocardial infarction. A cardiologist should be consulted; in case of a suspected infarction coronary angiography should be performed within < 24 hours, and if ST elevation and chest pain recur, without delay.

Reperfusion: emergency percutaneous coronary intervention (PCI) / thrombolytic therapy

• Choosing the most suitable reperfusion treatment option according to the patient’s needs and local conditions requires consultation with a cardiologist on call or with an emergency physician at a hospital.
• The first-line choice for reperfusion treatment is a primary PCI (PPCI) if that can be performed within less than 120 minutes after making the diagnosis. Thrombolytic therapy is an alternative if PPCI is not available.
• A PPCI is the first-line choice particularly if > 3 hours have passed since the onset of infarct pain, if there are contraindications for thrombolytic therapy (table T7) or if there is no treatment response to thrombolytic therapy within 60 minutes, or if the patient is hemodynamically unstable or a high-risk patient. Also uncertainty of the STEMI diagnosis (ventricular pacing, LBBB, difficulty in interpreting the ECG) speak for a PPCI.
  • Immediate PCI is the primary choice for the treatment of, particularly, elderly patients and those with risk of haemorrhage.
• Coronary angiograpy and a PPCI is recommended for patients
  • whose symptoms have continued for > 12 hours
  • whose ECG shows signs of ischaemia
  • who have recurrent chest pain and dynamic ECG changes, or signs of cardiac failure, of arrhythmias that threaten haemodynamics or of a cardiogenic shock.
• The results achieved with thrombolytic therapy are best if it is started rapidly within 1–2 hours of symptom onset. If a PPCI is not available, it is recommended to consider thrombolytic therapy for patients whose symptoms have started less than 12 hours ago if there are no contraindications for thrombolytic therapy (table T6). The benefit of the treatment is markedly reduced when more than 6 hours have elapsed from symptom onset and no benefit is to be expected when more than 12 hours have elapsed from the symptom onset.
• Agents used in thrombolytic therapy and their doses are presented in table T7.

• Patients who arrive for treatment with delay (12–48 h from the onset of symptoms) with no pain and even in a haemodynamically stable condition, who have had a STEMI may benefit from invasive assessment and treatment. Haemodynamically stable patients with no pain who have had an infarction more than 48 hours ago do not benefit from a routine revascularization of the infarct vessel.

Other medication in association with reperfusion

• Consult first with the cardiologist on call at the cardiology unit regarding the feasibility of primary PCI and the antithrombotic medication.
• Aspirin 250 mg to chew and swallow or 150 mg intravenously before both thrombolytic therapy and PPCI (see initial management )
• For other antithrombotic medication alternatives for patients with STEMI, see Table T8. Check local guidelines for treatment.
• Patients on anticoagulation therapy
  • Warfarin treatment within therapeutic range (INR 2.0–3.0) is continued. INR should be monitored daily; heparin therapy should not be started.
  • Direct anticoagulant therapy should be paused. Local guidelines should be followed and a cardiologist on call consulted.
• Patients with STEMI who decline reperfusion therapy, or in whom it is not possible due to comorbidities, should be treated with aspirin and/or clopidogrel (doses as prior to thrombolytic therapy) and with enoxaparin, or as considered suitable in the given situation.

Complications of thrombolytic therapy

• Intracranial bleed is a rare (1–2%) but serious complication of thrombolytic therapy. The signs of intracranial haemorrhage include a reduced level of consciousness, confusion and neurological deficits.
  • If haemorrhage is suspected, a CT scan of the head must be carried out.
• Intestinal and other bleeds (haematemesis, melaena) are more frequent (5–10%) than intracranial haemorrhage.
• Bleeding complications associated with thrombolytic therapy usually appear within 24 hours.
• Age > 75 years, female gender, systolic BP > 160 mmHg, lower body weight and concurrent anticoagulant therapy are factors increasing the risk haemorrhage.

Assessment of revascularization

• The most useful sign of successful thrombolysis is ST segment resolution ≥ 50% in the lead with the highest elevation within 60–90 minutes of the start of thrombolytic therapy.
• Alleviation of chest pain and reperfusion arrhythmias are suggestive findings but when appearing alone are not sufficient to confirm revascularization.
• Thrombolysis fails in about one third of patients, and reocclusion develops during hospitalisation in about 20% of patients after initial successful thrombolysis. In a large share of patients a significant occlusion remains in the coronary artery after thrombolysis.
• Patients who have received thrombolytic therapy are transported to a hospital with the capacity to perform a PPCI, where a coronary angiograpy is carried out within 24 hours,

Causes

• The mechanisms of arrhythmias include myocardial ischaemia and damage, reperfusion changes, autonomic imbalances as well as electrolyte and acid-base disturbances.
• Rapid reperfusion therapy (PPCI) should be pursued if any of the following is detected: ventricular fibrillation (VF), ventricular tachycardia (VT), frequent ventricular ectopic beats or disturbances in the AV conduction.

Ventricular fibrillation (VF)

• Primary VF occurring within 24–48 hours does not increase long-term risk of an arrhythmia or mortality.
• VF is treated with immediate defibrillation. Recurrent VF should be treated with defibrillation and by starting a beta blocker and/or amiodarone. Ischaemia induces recurrent VF; therefore, it should be rapidly evaluated by coronary angiography and revascularisation should be pursued.
• The risk of recurrence can be reduced by drug therapy for myocardial ischaemia and heart failure (adequate beta blockade, ACE inhibitors, nitrates). Similarly, electrolyte disturbances must be corrected as well as factors associated with fluid balance and oxygenation.

Ventricular tachycardia (VT)

• Repeated and prolonged episodes of VT are suggestive of a worsening heart disease and ischaemia, and when recurring they are an indication for rapid coronary angiography/PPCI.
• If VT episodes recur frequently, either a beta blocker or amiodarone should be administered intravenously. When VT is sustained or causes haemodynamic instability, it should be treated with immediate cardioversion, which is repeated as required.

Other ventricular arrhythmias

• Ventricular ectopic beats are common in patients with MI during the first few days of treatment. If they are asymptomatic and hemodynamically well-tolerated, no specific treatment is required.
• Idioventricular rhythm is a consequence of reperfusion and requires no specific treatment. Similarly, episodes of non-sustained VT (< 30 seconds) without haemodynamic effects require no specific treatment. None of the above mentioned arrhythmias serve as reliable predictors of VF.

Atrial fibrillation (AF)

• AF is common in the acute phase of an MI (10–20%). It increases in-hospital mortality and the risk of stroke, also in long-term follow-up.
• It is more prevalent in older patients with MI and in patients with left ventricular dysfunction or heart failure.
• Anticoagulant therapy should be started unless the patient is already on anticoagulant treatment; long-term therapy according to CHA₂DS₂-VASc criteria (see table in(Indications for and implementation of anticoagulant therapy in atrial fibrillation)); need for antithrombotic medication should be considered.
• In the case of AF with rapid ventricular rate, an intravenous, later oral beta blocker should be used to reduce ventricular rate. If the patient has cardiac failure or beta blockers are not suitable or not effective enough, intravenous amiodarone or digoxin may be used.

Sinus bradycardia and AV conduction disturbances

• Sinus bradycardia is common in the first few hours of an MI, particularly in inferior infarction. Medication reducing heart rate should be paused. Opioids may predispose to sinus bradycardia. If sinus bradycardia causes haemodynamic compromise it should be treated with atropine 0.5 mg intravenously, followed by supplemental doses of 0.2–0.3 mg up to 2.0 mg.
• First-degree AV block is often associated with inferior wall damage and is usually transient requiring no treatment.
• More serious conduction disturbances, such as second- and third-degree AV block as well as LBBB, RBBB and left fascicular block indicate extensive myocardial damage and a rapid coronary angiography is required. In such cases, temporary, sometimes even permanent, pacing is required. In second-degree AV block, atropine may improve the conduction. Isoprenaline may provide temporary help. Transient AV block is most commonly associated with an inferior MI.

Antiarrhythmic medication

• Antiarrhythmic and antibradycardia medications are presented in table T9.

• Right ventricular infarction is caused by the occlusion of the proximal right coronary artery.

Symptoms and diagnosis

• Clinical symptoms are hypotension and high venous pressure. However, a chest x-ray will fail to demonstrate venous congestion or pulmonary oedema.
• ST elevation ≥ 1 mm in lead V4R is strongly suggestive of right ventricular infarction. Q-waves and/or ST elevation in V1–V3 are also suggestive of right ventricular damage.
• AF may lead to haemodynamic collapse when the synchrony between the atria and ventricles is lost. AF must be treated promptly aiming to restore sinus rhythm. AV conduction disturbances are treated with atropine or dual chamber pacing.

Treatment

• Early reperfusion; see the treatment of STEMI
• Hypotension should be treated with adequate intravenous fluid loading, initially 500–1,000 ml, in order to maintain adequate preload. Dobutamine may be indicated.
  • Excessive fluid administration should be avoided after the initial phase to avoid loading the right ventricle.
• It is desirable to avoid drugs that lower blood pressure, such as ACE inhibitors, angiotensin receptor blockers, nitrates, diuretics and opioids.

• An imbalance in the myocardium with regard to the need and availability of oxygen may be triggered by anaemia, a surgical procecure, a severe systemic disease, an infection or trauma.
• When the acute condition improves, the myocardial ischaemia often improves or disappears.
• The diagnosis and treatment of ischaemia should be accomplished by following the aforementioned principles, taking into account the clinical starting points of each patient. Selection of antithrombotic medication should be considered case-by-case.
• The severity of the coronary artery disease should be assessed by echocardiography, coronary angiography, CT scan or myocardial perfusion scan, as necessary.

Monitoring and care

• Continuous cardiac monitoring in a surveillance unit is indicated during the first few treatment days.
• In an uncomplicated MI, a patient without chest pain is allowed to sit up straightaway, eat unassisted and use the commode at the bedside.
• In a complicated MI (heart failure, arrhythmias) bed rest should continue longer (2–4 days), mobilisation when considered appropriate.
• An ACE inhibitor [Evidence Level: A] should be introduced during the first 24 hours of treatment. If an ACE inhibitor is not suitable, an angiotensin receptor blocker should be prescribed.
• A beta blocker should be started during the hospitalisation period when the patient is haemodynamically stable.
• Nicotine replacement therapy is introduced for smokers [Evidence Level: A].
• Patient education and motivation for treatment is important. The patient should be given information about the disease, the modification of risk factors and other medication.

Treatment chain

• Treatment of a patient with MI may justifiably be carried out within primary care if the treatment options are limited due to other diseases.

• The follow-up management of ACS consists of modification of risk factors with lifestyle changes and pharmacotherapy, as well as antithrombotic and anti-ischaemic drug therapy.
• Aspirin permanently 100 mg daily. Clopidogrel 75 mg daily for patients with aspirin allergy.
• An ADP receptor inhibitor (ticagrelor, clopidogrel or prasugrel) is used in the treatment of ACS; both during the acute hospital phase and in the continued treatment (12 months) after the MI; 6 months if bleeding risk is increased. In special situations, when the risk of ischaemia is high without increased risk of bleeding, continuing the medication with aspirin + an ADP receptor inhibitor (ticagrelor 60 mg twice daily) more than 12–36 months may be considered.
• If anticoagulation therapy (warfarin, dabigatran, rivaroxaban, apixaban, edoxaban) is necessary due to some other indication, after insertion of a coronary stent the patient is given triple therapy (aspirin + clopidogrel + anticoagulant) for 5 days to 1 month (individual assessment taking into account antithrombotic and anti-ischaemic drug effects as well as bleeding risk), then clopidogrel (or aspirin) + anticoagulant for a total of one year after the cardiac event. After one year, only anticoagulant is used.
• Anticoagulant therapy is indicated for patients with a left ventricular thrombus, for 3–6 months. In association with recently appeared AF, the long-term need of anticoagulant therapy is assessed with CHA₂DS₂VASc criteria (Indications for and implementation of anticoagulant therapy in atrial fibrillation). It is recommended to consider a direct oral anticoagulant, due to the smaller risk of an intracranial bleeding.
• An ACE inhibitor should be prescribed for MI patients with heart failure (in the acute phase), EF < 40%, anterior infarction, hypertension or diabetes. The recommended maintenance doses should be used, or the highest tolerated dose. If an ACE inhibitor is not suitable, an angiotensin receptor blocker can be prescribed.
• A statin should be prescribed for all patients with MI. Ezetimibe or PCSK9 inhibitors can be used when statins are not suitable or more intensive treatment is needed; see Treatment of dyslipidaemias (Treatment of dyslipidaemias).
• A beta blocker should be prescribed for those patients with MI who also have cardiac failure or EF ≤ 40%, unless contraindicated.
• Calcium-channel blockers are mainly appropriate for the treatment of hypertension and/or chest pain if beta blockers are not suitable. There is no clear evidence of the benefit of calcium-channel blockers in terms of improved prognosis in CHD. See Chronic coronary syndrome (Coronary heart disease).
• A prescription for short-acting glyceryl trinitrate (GTN) should always be given to the patient on discharge after an MI.
• Long-acting nitrates are reserved for patients with continuing chest pain.
• Influenza immunization [Evidence Level: C] is indicated for all patients who have had an MI.
• After the hospitalisation phase, the long-term management of patients who have sustained an MI will almost without exception be the responsibility of their own health centre. Primary care health providers are in a key position to motivate the patient to adopt permanent lifestyle changes and to ensure that effective drug therapies to manage risk factors and improve prognosis are adhered to and that regular primary care follow-up visits are arranged.
  • The first checkup should be arranged within 3 months from discharge from hospital.
  • To optimize the treatment of risk factors, checkup visits are usually needed at 3, 6 and 12 months and subsequently once a year.
• Emphasis should be put on patient guidance (lifestyle changes, diet, exercise) both during the hospital stay and after that in the primary care. The progress of the changes should be actively monitored during follow-up visits. These factors are important in rehabilitation of the patient back into normal life.
• Patients who have had an ACS will benefit from individually planned cardiac rehabilitation. See local guidelines and procedures.