Myocardial Infarction

1
Myocardial Infarction

• Zohair Y. J. Al-Hariri
• King Khalid University Hospital
• King Saud University
• Riyadh, Saudi Arabia

2
What is MI?

• Myocardial infarction is the death of part of the
  heart muscle due to its sudden loss of blood
  supply.
• Death of the heart muscle often causes chest pain
  and electrical instability of the heart muscle
  tissue.
• Approximately one million Americans suffer a
  heart attack annually.
• Approximately 90 to 95 of heart attack victims
  who reach the hospital survive.

3
What causes MI?

• A MI is caused by the formation of a blood clot
  on a cholesterol plaque.
• Cholesterol plaque is the formation of a hard,
  thick substance within the artery walls which is
  caused by deposits of cholesterol in the artery
  walls
• During exercise or excitement, the narrowed
  coronary arteries cannot increase the blood
  supply to meet the increased oxygen demand of the
  heart muscle.
• Occasionally the surface of the cholesterol
  plaque in the artery may rupture, then completely
  occludes blood flow in the vessel and results in
  a heart attack.

4
What causes MI?(cont.)

• Irreversible risk factors
• Age
• Gender
• Family history
• Potentially reversible risk factors
• Hyperlipidaemia
• Smoking
• Hypertension
• Other factors

5
What are the symptoms of MI?

• Chest pain or pressure is a common symptom of MI.
• Cardiac chest pain is often vague.
• MI frequently occur from 400 A.M. to 1000 A.M.
• Interestingly, MI do not usually happen during
  exercise.
• Approximately one quarter of all heart attacks
  are silent, without chest pain.
• Heart attack victims may complain of

• chest pressure
• sweating
• jaw pain
• heartburn and/or indigestion
• SOB

• arm pain (more commonly the left arm, but may be
  either)
• upper back pain
• general malaise (vague feeling of illness)
• nausea

6
How is a MI diagnosed?

• The initial diagnosis of MI is made by a
  combination of clinical symptoms and
  characteristic ECG changes.
• Confirmation of MI can only be made hours later
  through detection of elevated cardiac enzymes.
• Other investigations.
• Rapid evaluation allows early treatment of
  potentially life-threatening arrhythmias, and
  permits early reperfusion.
• NB Achieving PROMPT MEDICAL ATTENTION is the THE
  MOST IMPORTANT FACTOR for an improved prognosis
  with a heart attack.

7
What are the treatment options for an MI?

• Recanalisation.
• Optimal benefit is obtained if reperfusion can be
  established in the first 4- 6 hours of the
  attack.
• Cardiac catheterization facility (PTCA).
• The angiogram allows evaluation of the status of
  the other coronary arteries.
• Stenting.
• Addition of newer super aspirins

8
What are the treatment options for an MI? (cont.)

• Thrombolytic agents.
• Anti-platelet agents.
• Heparin.
• Nitroglycerin.
• ACE inhibitors.
• Beta blocking agents.
• coronary artery bypass graft (CABG) surgery.

9
How does a patient recover from MI?

• MI patients are monitored in the hospital for 3
  or more days prior to discharge home.
• Arrythmias, shortness of breath due to heart
  failure, or recurrent pain are indications for
  further therapy.
• Patients gradually increase their activity under
  observation.
• After a small heart attack, patients can usually
  resume normal activities after two weeks.
• A moderate heart attack requires limited,
  gradually increasing activity for up to four
  weeks. A
• Large heart attack may result in a recovery
  period of six weeks or longer.

10
How to prevent MI recurrence?

• Aspirin and beta blockers.
• Stopping smoking, reducing weight and dietary
  fat, controlling blood pressure and diabetes,
  along with regular, carefully prescribed
  exercise.
• Reduction of LDL cholesterol to a value below 100
  mg/dl has been particularly demonstrated to have
  a beneficial effect on long-term prognosis.
• ACE inhibitors.
• Further cardiac stress testing.

11
What is in the future of MI patient?

• Greater public awareness and lifestyle changes.
• Hirudin and Hirulog, are being tested to
  complement current therapies.
• The role of the super aspirins (Reopro,
  Integrellin, and Aggrastat) is currently being
  investigated as well.
• Newer versions of t-PA are being developed.
• With the widespread application of modern
  in-hospital and out of hospital programs for
  heart attack patients, the long-term prognosis
  following a heart attack will only improve.