Table 1. Circulatory Conditions and Their Treatment after Myocardial Infarction

Condition and TreatmentSymptoms and Signs

Treatment in Hospital

Follow-up and Treatment

• Pain: morphine, nitro, beta-blocker
• Blood pressure
• Skin, peripheral circulation
• Increased respiratory rate suggests cardiac insufficiency.
• Monitoring of arrhythmias
• ST segment changes
• Oxygen saturation; oxygen or continuous positive airway pressure (CPAP)
• A comfortable posture
• Informing and reassuring the patient
• Nicotine replacement therapy is started already in the hospital. Nicotine addiction may be evaluated by using the Fagerstrom test, and the planning of further treatment may be based on it.
• In an uncomplicated infarction, patients are allowed to sit as soon as they want, they can eat unassisted, and they can be helped to a portable toilet at the bedside. Intensive monitoring is usually needed for 1 to 2 days.
• The infarction is complicated and treatment lasts longer if the patient has had
  • Shock
  • Hypotension
  • Obvious cardiac insufficiency (usually requires thrombosis prophylaxis or anticoagulation, especially if in connection with atrial fibrillation)
  • Prolonged chest pain
  • Serious ventricular arrhythmias
  • Thromboembolic complications
  • Anatomical complications (papillary muscle dysfunction or rupture)
  • Pericarditis on days 2 to 4
• Treatment of the patient in primary health care (in a primary health care hospital) is justifiable if the patient's prognosis is otherwise poor: those who are permanent inpatients or otherwise severely disabled and for whom invasive treatment has not been planned.

Assessment of Risk Factors in a Patient with Myocardial Infarction

• The most important causes of mortality are
  • Reinfarction
  • Cardiac insufficiency
  • Arrhythmias
• During hospitalization, a poor prognosis is indicated by
  • Cardiac insufficiency and extensive infarction (ejection fraction [EF] <25%)
  • Chest pain and ischaemic ST changes (send to angiography)
  • In connection with non-Q-wave infarction, risk factors for coronary heart disease (CHD) and especially diabetes mellitus
• Evaluation of ischaemia and need for active treatment
  • Risk is highest during the first few weeks and months after infarction. Therefore, at the end of the hospital treatment, an early symptom-limited exercise test is performed on many patients to estimate the need for angioplasty and coronary surgery in particular. Refer to Table 2 in the original guideline document for more information on the assessment of risk of reinfarction and patient's prognosis.
• For indications of coronary angiography, see the NGC summary of the Finnish Medical Society Duodecim guideline Coronary Angiography and Indications for CABG or Angioplasty.

Care after Myocardial Infarction

Drug Treatment

• Aspirin, beta-blocker (Freemantle et al., 1999; DARE-999336, 2001; Sudlow et al., 2002) [A], ACE inhibitors, and statins have been shown to improve the prognosis. Glycaemic control is also important.
• Unnecessary drugs instituted during the initial phase should be discontinued already towards the end of hospital treatment or when the patient comes to the first check-up, not on the last day in hospital.
• Only those with cardiac insufficiency or poorly controlled blood pressure need a diuretic.
• Aspirin 50 to 100 (to 250) mg is given unless there are contraindications ("Collaborative overview of randomised trials of antiplatelet therapy," 1994; DARE-948032, 1999) [A].
• Patients with hypertension, angina pectoris, ventricular arrhythmias, ischaemia during an exercise test, previous infarction, an enlarged heart, low ejection fraction, or a cardiac insufficiency need a beta-blocker. In practice, these drugs are given to all patients who have no contraindications. Adequate beta-blockade is achieved when the heart rate at rest is about 60 bpm.
• Nitrate plus a beta-blocker are given to all patients with angina pectoris or ischaemia during an exercise test. Nitrate is a drug used for symptom relief that can often be discontinued.
• An ACE inhibitor is given to all patients with clear systolic dysfunction (ejection fraction <40%) (Sudlow et al., 2002) [A]. A milder systolic dysfunction is treated with an ACE inhibitor if the patient has cardiac insufficiency (symptomatic or asymptomatic), valvular regurgitation, hypertension, or diabetic nephropathy. The indications of ACE inhibitors have been constantly extended, and they are now given to almost every patient who has had an infarction. So-called "asymptomatic cardiac insufficiency" and even secondary prevention (according to the Heart Outcomes Prevention Evaluation [HOPE] study) in high-risk patients have become indications (Yusuf, 2000). ACE inhibitor therapy may be more difficult if the patient has a valvular obstruction, hypotension, or uraemia. Patients on diuretics have a risk of hypotension, especially when treatment with an ACE inhibitor is started. The ACE inhibitor dose should not remain at the level of the initial dose unless hypotension and creatinine elevation prevent the titration.
• A lipid-lowering drug (a statin) is given to all patients with serum low-density lipoprotein (LDL) cholesterol >3.0 mmol in spite of the diet (Rembold, 1996; DARE-961089, 1999) [A]. For calculation of the level, see the LDL cholesterol calculator program available on the EBM CD-ROM and the EBM Web site.
• An anticoagulant is given if the patient has atrial fibrillation, an embolic complication, or ventricular aneurysm verified by echocardiography, often also short-term in the treatment of an extensive anterior wall infarction.
• Elevated serum homocysteine concentration is associated with cardiovascular diseases, but it does not appear to predict arterial disease in healthy persons (Knekt et al., 2001; Institute for Clinical Systems Improvement [ICSI], 2003; HTA-20030537, 2004) [C]. See also the NGC summary of the Finnish Medical Society Duodecim guideline Coronary Heart Disease (CHD): Symptoms, Diagnosis, and Treatment.
• A quiet moment should be reserved for discussing life after MI and living with coronary artery disease (CAD) while the patient is still in the hospital.
  • Such a discussion helps to reduce psychological problems and disability.
  • Give instructions for dealing with possible exacerbation of the disease.
  • The motivation to quit smoking is highest after an infarction:
    • nicotine replacement therapy according to individual evaluation (Fagerstrom test)
  • A cholesterol and saturated fatty acid-restriction diet and/or drug treatment
  • Exercise counseling according to individual evaluation: the patient must be able to talk while exercising.
  • Rehabilitation course
  • Secondary prevention

Sick Leave

• Duration 2 to 3 months
• Reexamination after about one month, usually within specialist health care.
  • History of symptoms: if the patient has had angina pectoris symptoms, consider testing exercise capacity, if the test has not been performed yet.
  • Remind the patient of the principles of healthy life style.
  • Serum lipids should be measured if they were high on an earlier measurement.
  • Control the adequacy of beta-blockade: target heart rate 50 to 60 bpm.
  • Possible depression should be diagnosed.
• The ability to work is evaluated before the end of the sick leave. If necessary, an exercise test is carried out to assess working ability.

Related Evidence

• Glucose-insulin-potassium probably reduces mortality in acute MI. However, its role in combination with thrombolysis or acute revascularization should be determined by larger randomized trials (Fath-Ordoubadi & Beatt, 1997; DARE-971070, 1999) [B].
• There is little evidence from randomized trials of any significant further net clinical benefit from adding either subcutaneous or intravenous unfractionated heparin to the treatment of patients who are given aspirin (Collins et al., 1996; DARE-978036, 1999) [B].
• Low-dose amiodarone may have a beneficial effect on total mortality after MI, but the drug has many adverse effects (Zarembski et al., 1993; DARE-940032, 1999) [C].
• Class I antiarrhythmic agents increase the risk of death after MI (Sudlow et al., 2002) [A].
• Sotalol increases mortality in patients with MI who have left ventricle failure (Sudlow et al., 2002) [B].
• The evidence does not support the hypothesis that verapamil use is associated with harm in patients with MI (Pepine, Faich, & Makuch, 1998; DARE-981601, 2000) [B].
• Exertion-related MIs occur in habitually inactive people with multiple cardiac risk factors (Giri et al., 1999) [B].
• C-reactive protein may have independent value as a predictor of cardiovascular disease risk, but conclusive evidence on its role in risk assessment is lacking (Institute for Clinical Systems Improvement [ICSI], 2003; Health Technology Assessment Database: HTA-20030537, 2004; Blue Cross Blue Shield (BCBS), 2003; HTA-20030742, 2004;Health Technology Advisory Committee [HTAC], 2002; HTA-20030446, 2004) [C].

Definitions:

Levels of Evidence

1. Strong research-based evidence. Multiple relevant, high-quality scientific studies with homogeneous results.
2. Moderate research-based evidence. At least one relevant, high-quality study or multiple adequate studies.
3. Limited research-based evidence. At least one adequate scientific study.
4. No research-based evidence. Expert panel evaluation of other information.

CLINICAL ALGORITHM(S)