Links to other pages within Patient UK which are related to this topic:
Experience | Leaflets | Support | Patient+ | Guidelines | Weblinks | Poems | Videos | News | Products | Other
Print options:   Other options:   Bookmark and Share

This is a PatientPlus article. PatientPlus articles are written for doctors and so the language can be technical. However, some people find that they add depth to the articles found in the other sections of this website which are written for non-medical people.

Acute Myocardial Infarction

Post your experience
See others (19 there)

Myocardial infarction is now considered part of a spectrum referred to as acute coronary syndromes, which refers to a range of acute myocardial ischaemia, that also includes unstable angina and non-ST segment elevation myocardial infarction. The new criteria for diagnosing myocardial infarction are an increase in biochemical markers of myocardial necrosis, with at least one of the following:

  • Ischaemic symptoms
  • Development of pathological Q waves on the ECG
  • ECG changes indicative of ischaemia (ST segment elevation or depression)
  • Coronary artery intervention (e.g. angioplasty)
Epidemiology
  • Coronary heart disease is the most common cause of death in the UK. CHD is responsible for the deaths of approximately one in five men, and one in six women.1
  • The average incidence of myocardial infarction for those aged between 30 and 69 years is about 600 per 100,000 for men, and 200 per 100,000 for women.1
  • A male predominance in incidence exists up to approximately age 70 years, when the sexes converge to equal incidence.
  • Pre-menopausal women appear to be protected from atherosclerosis. Incidence increases with age and elderly people also tend to have higher rates of morbidity and mortality from their infarcts.

Risk Factors

  • Non-modifiable risk factors for atherosclerosis: increasing age, male, family history of premature coronary heart disease, premature menopause
  • Ethnic Group: In the UK, the highest recorded rates of coronary artery disease mortality are in people born in India, Pakistan and Bangladesh2
  • Modifiable risk factors for atherosclerosis: smoking, diabetes mellitus (and impaired glucose tolerance), hypertension, raised LDL cholesterol, reduced HDL cholesterol, obesity, inactivity
Presentation
  • Chest pain: three quarters of patients present with characteristic central or epigastric chest pain radiating to the arms, shoulders, neck, or jaw. The pain is described as sub-sternal pressure, squeezing, aching, burning, or even sharp pain. Radiation to the left arm or neck is common. Chest pain may be associated with sweating, nausea, vomiting, dyspnoea, fatigue, or palpitations.
  • Shortness of breath: may be the patient's anginal equivalent or a symptom of heart failure.
  • Atypical presentations are common (especially women, older men, people with diabetes, and people from ethnic minorities) e.g. abdominal discomfort or jaw pain; elderly patients may present with altered mental state.

Signs

Examination findings can vary enormously:

Differential diagnosis

Consider non-atherosclerotic causes in younger patients or if there is no evidence of atherosclerosis: coronary emboli from sources such as an infected cardiac valve, coronary occlusion secondary to vasculitis, coronary artery spasm, cocaine use, congenital coronary anomalies, coronary trauma, increased oxygen requirement (e.g. hyperthyroidism) or decreased oxygen delivery (e.g. severe anaemia)

Investigations
  • If diagnosis is suspected arrange urgent admission immediately (999 Ambulance).
  • ECG: may be helpful pre-hospital setting if the diagnosis is uncertain or in a remote area in the assessment for pre-hospital thrombolysis, but otherwise should not delay getting the patient to hospital.
    Features that increase the likelihood of infarction: new ST segment elevation; new Q waves; any ST segment elevation; new conduction defect. Other features of ischaemia are ST segment depression and T wave inversion.

In hospital

  • Full blood count to rule out anaemia; leucocytosis is common; monitor potassium levels (electrolyte disturbances may cause arrhythmias, especially potassium and magnesium); renal function (eGFR) should be measured prior to starting an ACE inhibitor. Lipid profile needs to be obtained at presentation because levels can change after 12-24 hours of an acute illness. Measure CRP and other markers of inflammation.
  • Cardiac enzymes: cardiac troponins T and I are highly sensitive and specific for cardiac damage. The risk of death from an acute coronary syndrome is directly related to troponin level and patients with no detectable troponins have a good short-term prognosis. Serum levels increase within 3-12 hours from the onset of chest pain, peak at 24-48 hours, and return to baseline over 5-14 days. Myocardial muscle creatine kinase (CK-MB) is found mainly in the heart. CK-MB levels increase within 3-12 hours of onset of chest pain, reach peak values within 24 hours, and return to baseline after 48-72 hours. Sensitivity and specificity are not as high as for troponin levels.
  • Serial ECGs and continuous ECG monitoring in CCU.
  • Chest x-ray: to assess patient's heart size and the presence or absence of heart failure and pulmonary oedema.
  • Cardiac catheterisation and angiography: cardiac angiography defines the patient's coronary anatomy and the extent of the disease. Whether all patients with acute myocardial infarction should ideally undergo cardiac catheterization is controversial and present consensus is for angiography only if indicated by recurrent chest pain or significant ischaemia shown by exercise ECG or perfusion imaging. Patients with cardiogenic shock, intractable angina despite medications or severe pulmonary congestion should undergo cardiac catheterization and revascularization immediately.
  • Echocardiography can define the extent of the infarction and assess overall ventricular function and can identify complications, such as acute mitral regurgitation, left ventricular rupture or pericardial effusion.
  • Myocardial perfusion scintigraphy using SPECT: NICE recommends that myocardial perfusion scintigraphy using SPECT should be the first test used for:3
    • People where stress ECG may not give accurate or clear results, e.g. women, people who have certain unusual patterns in the electrical activity of their heart, people with diabetes or people for whom exercise is difficult or impossible.
    • The diagnosis of people who are less likely to have coronary artery disease and who are at lower risk of having heart problems in the future. The likelihood of a person having coronary artery disease can be assessed by considering a number of factors, e.g. age, sex, ethnic background and family history as well as the results of physical examination and investigations.
    • As an investigation in people who still have symptoms following a myocardial infarction or despite having had treatment to improve coronary artery blood flow.
Prognosis
  • After a first myocardial infarction:1
    • 23% of people die before reaching hospital
    • 13% die during hospital admission
    • 10% die within the first year following hospital discharge
    • 5% die each year thereafter (this persists indefinitely)
  • Prognosis correlates with the degree of myocardial necrosis. Greater degrees of myocardial necrosis are associated with a worse prognosis. The degree of myocardial necrosis can be estimated by various factors, e.g.1
    • The rise in serum troponin T
    • Degree and extent of ECG changes
    • Degree of left ventricular dysfunction on echocardiography
  • Prognosis is worse in women, increasing age, increasing ventricular dysfunction, ventricular dysrhythmias and recurrent infarction. Other indicators of poorer prognosis are delay in reperfusion or unsuccessful reperfusion, anterior infarction, number of leads showing ST elevation, bundle branch block and systolic blood pressure less than 100 mm with tachycardia greater than 100 per minute.
  • Better prognosis is associated with early reperfusion, inferior wall infarct, preserved LV function, short-term and long-term treatment with beta-blockers, aspirin, statins and ACE inhibitors.
  • Elderly patients with acute MI are at increased risk of developing complications and should be treated aggressively.

Document references
  1. Myocardial infarction - secondary prevention, Clinical Knowledge Summary
  2. Bhopal R, Unwin N, White M, et al; Heterogeneity of coronary heart disease risk factors in Indian, Pakistani, Bangladeshi, and European origin populations: cross sectional study. BMJ. 1999 Jul 24;319(7204):215 [abstract]
  3. NICE Technology Appraisal; Coronary imaging: Myocardial perfusion scintigraphy for the diagnosis and management of angina and myocardial infarction (November 2003)
  4. Myocardial Infarction: secondary prevention, NICE Clinical Guideline (2007)

Internet and further reading Acknowledgements EMIS is grateful to Dr Colin Tidy for writing this article. The final copy has passed scrutiny by the independent Mentor GP reviewing team. ©EMIS 2008.
DocID: 1761
Document Version: 21
DocRef: bgp539
Last Updated: 9 Jan 2008
Review Date: 8 Jan 2010

The authors and editors of this article are employed to create accurate and up to date content reflecting reliable research evidence, guidance and best clinical practice. They are free from any commercial conflicts of interest. Find out more about updating.

Patient UK Hearing Impairment Survey

Patient UK are grateful to the 550 people who took part in this survey.
To see the results click here.
If you'd like to leave your feedback, please go to our interactive forum.

Links to other pages within Patient UK which are related to this topic:
Experience | Leaflets | Support | Patient+ | Guidelines | Weblinks | Poems | Videos | News | Products | Other
Print options:   Other options:   Bookmark and Share
Want to search some more? Use the Google Search box below to search our site.

Related pages in Patient UK

Your Experience (^ top of page)

 Please add your experience about this condition / medicine
 View Patient Experience for 'Acute Myocardial Infarction' (19 there)
 Myocardial Infarction - After the MI
 Myocardial Infarction - Medication
 Myocardial Infarction (Heart Attack)

Support Group British Heart Foundation
Support Group Chest Heart & Stroke Scotland
Support Group Chest, Heart & Stroke Northern Ireland

 Acute Coronary Syndromes (ACS)
 Acute Myocardial Infarction Management
 Cardiac Enzymes and Markers for Myocardial Infarction
 Cardiac Rehabilitation
 Cardiac Type Chest Pain Presenting in Primary Care
 Cardiovascular History and Examination
 Complications of Acute Myocardial Infarction
 Coronary Revascularisation
 ECG A Methodical Approach
 Epidemiology of IHD
 Flying with Medical Conditions
 Posterior Myocardial Infarct (PMI)

 Guidelines on Acute Coronary Syndromes
 Guidelines on Myocardial Infarction

 Angina
 Heart Attack (Myocardial Infarction)

 A Memorable Day

 Links to online videos on Myocardial Infarction

Recent related news items

 Is routine aspirin use not advised?
 Aspirin 'only for heart patients'
 Women have 'same heart symptoms'
 Swine Flu Vaccine: Watching For Side Effects
 Study: Flu viruses can spark heart attacks - The Associated Press

All news by related topic

 Myocardial Infarction news

Medical equipment


Visit the Patient UK Medical Equipment shop

Books

 Angina & Heart Attacks : British Medical Association's Family Doctor Series
 Angiology, the Next Medical Revolution: Prevent Your Heart Attack or Stroke
 Heart Attack (Stop That)
 Heart Attack or Stroke (Prevent Your): Angiology, the Next Medical Revolution

Visit the Patient UK shop

Other - Useful resources (^ top of page)

Pictures, diagrams, photos, images, etc.
Evidence based medicine
Online textbooks and journals
UK Guidelines
Online Videos
Medline
Other good health sites

Want to search some more? Use the Google Search box below to search our site.

Advertisements











Disclaimer: Patient UK has no control over the content of any external links above. Inclusion does not imply endorsement by Patient UK.

Want to advertise on this site? Find out how >>

Clicking here will take you to the foot of this page where you'll find a list of Information Leaflets which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Support Groups which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Medicines & Drugs which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of diagrams which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of PatientPlus (detailed reference) articles which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of UK Guidelines which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of other selected websites which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Poems and Stories which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Operations and Procedures which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Online Videos which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find links through to our interactive forum.
Here you can follow a link to view existing patient experiences on this subject, or to add your own
Clicking here will take you to the foot of this page where you'll find links to news stories on this subject in our Online Newspaper
Clicking here will take you to the foot of this page where you'll find links to related products
Clicking here will take you to the foot of this page where you'll find links to other useful sources of information
Click here to open a printer-friendly version of this document, in a new window, together with the print dialogue box
Click here to open this document in PDF format
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Click here to listen to the MP3 audio recording of this document
Click here to download the audio recording of this document as a podcast, for listening to at your leisure
Click here to open our Dictionaries and Glossaries page
Click here to see related products in our Online Pharmacy
Note: this will open in a new window
Click here to add this page to a social bookmarking site of your choice
Click here if you want to find out more about social bookmarking. This link will take you to the Wikipedia explanation
Note: this will open in a new window
Clicking here will take you to the foot of this page where you'll find a list of Information Leaflets which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Support Groups which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Medicines & Drugs which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of diagrams which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of PatientPlus (detailed reference) articles which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of UK Guidelines which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of other selected websites which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Poems and Stories which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Operations and Procedures which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find a list of Online Videos which are related to the topic you are currently viewing
Clicking here will take you to the foot of this page where you'll find links through to our interactive forum.
Here you can follow a link to view existing patient experiences on this subject, or to add your own
Clicking here will take you to the foot of this page where you'll find links to news stories on this subject in our Online Newspaper
Clicking here will take you to the foot of this page where you'll find links to related products
Clicking here will take you to the foot of this page where you'll find links to other useful sources of information
Click here to open a printer-friendly version of this document, in a new window, together with the print dialogue box
Click here to open this document in PDF format
This will offer you the usual PDF options i.e. document navigation, search, zoom and formatted print
Note: this is the best way to print the document
Click here to listen to the MP3 audio recording of this document
Click here to download the audio recording of this document as a podcast, for listening to at your leisure
Click here to open our Dictionaries and Glossaries page
Click here to see related products in our Online Pharmacy
Note: this will open in a new window
Click here to add this page to a social bookmarking site of your choice
Click here if you want to find out more about social bookmarking. This link will take you to the Wikipedia explanation
Note: this will open in a new window
Click here to return to the home page
Click here to read our 'About Us' page
Go to the Emis Access website, where you can book an appointment with your GP, order a repeat prescription or view you medical record online.
Note: this will open in a new window
View and/or join in discussion about health, lifestyle and disease in our interactive forum.
Note: this will open in a new window
Go to our pharmacy product price comparison pages.
Go to our online newspaper for current medical news and commentary.
Note: this will open in a new window
Adverts on this site do not influence the medical content. Click to read more.
Adverts on this site do not influence the medical content. Click to read more.