Myocardial infarction

Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a serious, sudden heart condition usually characterized by varying degrees of chest pain or discomfort, weakness, sweating, nausea, vomiting, and arrhythmias, sometimes causing loss of consciousness. It occurs when a part of the heart muscle is injured, and this part may die because of sudden total interruption of blood flow to the area. It is often a life-threatening medical emergency which demands both immediate attention and activation of the emergency medical services.

Treatment

A heart attack, especially because of cardiac arrhythmias, is often a life-threatening medical emergency which demands both immediate attention and activation of the emergency medical services. Immediate termination of arrhythmias and transport by ambulance to a hospital where advanced cardiac life support (ACLS) is available can greatly improve both chances for survivial and recovery. The more time that passes, even 1-2 minutes, before medical attention is available/sought, the more likely the occurrence of both (a) life threatening arrhythmias/death and (b) more severe and permanent the heart damage.

Related Topics:
Cardiac arrhythmias - Medical emergency - Emergency medical services - Ambulance - Hospital - Advanced cardiac life support

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First line

In the hospital, oxygen, aspirin, nitroglycerin and analgesia (usually morphine, hence the popular mnemonic MONA) are administered as soon as possible, if this has not already happened during transport.

Related Topics:
Oxygen - Aspirin - Nitroglycerin - Analgesia - Morphine - Mnemonic

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Reperfusion

The ultimate goal of the management in the acute phase of the disease is to salvage as much myocardium as possible and restore contractile function of heart chambers. This is achieved primarily with thrombolytic drugs, such as streptokinase, urokinase, alteplase (recombinant tissue plasminogen activator, rtPA) or reteplase. Heparin alone as an anticoagulant is substandard.

Related Topics:
Thrombolytic - Streptokinase - Urokinase - Alteplase - Heparin - Anticoagulant

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Although clinical trials suggest better outcomes, angioplasty as a first-line measure is probably still underused. This is largely dependent on the availability of an experienced interventional cardiologist on-site, or the availability of rapid transport to a referral centre.

Related Topics:
Angioplasty - Interventional cardiologist

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Emergency coronary surgery, in the form of coronary artery bypass surgery is another option, although this option is in decline since the development of primary angioplasty. The same limitations apply here: cardiothoracic surgery services are not available in many hospitals.

Related Topics:
Coronary artery bypass surgery - Cardiothoracic surgery

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NSTEMI (non-ST elevation MI) is initially indistinguishable from unstable angina in most cases, and is therefore managed similarly with aspirin, heparin and usually with clopidogrel.

Related Topics:
Unstable angina - Aspirin - Heparin - Clopidogrel

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Monitoring and follow-up

Additional objectives are to prevent life-threatening arrhythmias or conduction

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disturbances. This requires monitoring in a coronary care unit and protocolised administration of antiarrhythmic agents.

Related Topics:
Coronary care unit - Antiarrhythmic agent

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Long-term beta-blocker medication is routinely commenced. Patients are also initiated on aspirin and/or clopidogrel (Plavix® or Iscover®); other anticoagulant drugs have not shown additional benefit. ACE inhibitors are commenced in the course of follow-up to assist in ventricular remodeling. Recent studies have shown benefit of the initiation of a statin (e.g. simvastatin 40 mg daily), even in patients without known hypercholesterolemia.

Related Topics:
Beta-blocker - Aspirin - Clopidogrel - Anticoagulant - ACE inhibitor - Ventricular remodeling - Statin - Simvastatin - Hypercholesterolemia

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Patients are discouraged from working and sexual activity for about two months, while they undergo cardiac rehabilitation training. Local authorities may place limitations on driving motorised vehicles.

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During a follow-up outpatient visit, or increasingly before discharge from hospital, it will be determined if the patient suffers from angina pectoris. If this is the case, treadmill testing, thallium scintigraphy or coronary angiography are often performed to identify treatable causes, as this will decrease the risk of future myocardial infarction.

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