Ischemic Heart Disease

Question 1

Coronary Artery Disease

Answer 1

Plaque development in the larger arteries supplying blood to cardiac muscle.
Sudden change in coronary artery du to activation of an atherosclerotic plaque. No matter what patient does, the chest discomfort does not go away.
The trigger for plaque rupture is not completely understood.
Plaque rupture exposes injured tissue to the bloodstream, which attracts platelets to try and repair, but in the process become activated. They start covering the plaque and amount of blood flow in the lumen may be reduced.
Large numbers of platelets will then further trigger clotting cascade and RBC clotting factors in blood will cause thrombus on top of platelets.
This rapid rupture may result in total occlusion of artery, which then triggers myocardial infarction.

Question 2

Myocardial Infarction

Answer 2

From a severe sudden occlusion=30% death rate.
Acute ischemia destabilizes the patients hear rhythm, causing cardia arrest, which is why many patients die before reaching the hospital.
Heart rhythm goes into ventricular fibrillation-electrical defibrillation can shock person back into rhythm.
Blockages at the beginning of coronary arteries, which control large territory of heart muscle, cause large heart attacks, substantial cardiac damage, and may result in heart failure.
Complications:
Heart Failure
Rupture of wall in the heart
Rupture of a portion of the heart muscle called papillary muscle, which may results in sudden failure of mitral valve.
Aneurysm formation
Sudden death
Long-term Therapy:
Modify risk factors
Administer agents that inhibit platelet function (aspirin)
Beta blockers (reduce risk of sudden death and reduce risk of heart failure after MI)
Cholesterol-lowering agents (lower cholesterol and lipids)
Angiotensin-converting enzyme inhibitors (help prevent development of heart failure and cardiac enlargement over time)

Question 3

Causes of Angina

Answer 3

Demand goes up or supply goes down.

Question 4

The Ischemic Cascade: Detecting Coronary Artery Disease

Answer 4

1. Perfusion Abnormality (Nuclear Profusion Scan)
2. Abnormal Metabolism (Metabolism Scan)
3. Regional failure of mechanical function (Wall motion study: Echo or MRI)
4. Electrocardiogram changes (Electrocardiogram monitor)
5. Angina (Patient Symptoms)