Myocardial Ischemia, Injury & Infarction

Chapter 15

Robert J. Huszar, MD

Instructor

Patricia L. Thomas, MBA, RCIS

Outline

• Coronary Artery Circulation

• Coronary Artery Disease

• Acute Coronary Syndromes

• Acute Myocardial Syndrome

Coronary Artery Disease/Risk Factors

• Family History• Gender• Race• Age• Cigarette Smoking• Diabetes Mellitus• Hypertension• Elevated Cholesterol• Obesity• Lack of Exercise• Stress• Cocaine Use

Pathophysiology of CAD

• Phase 1: Appearance of an atheromatous Plaques

• Phase 2: Formation of thrombus on the surface of the plaque after erosion or rupture– Erosion: endothelial covering of the plaque is torn

away– Rupture: fibrous cap is weakened/surge of blood

pressure/vasospasm

• Phase 3: Resolution or Occlusion

Myocardial Ischemia, Injury & Infarction

Results from the failure of local CA to supply sufficient oxygenated blood to the myocardial tissue.– Occlusion or obstruction:atherosclerotic CA with

blood clots– CA Spasm caused by constriction of smooth muscle

in the wall of the CA.– Other reasons such as arrhythmia, PE, Hypotension

or shock– Increased Myocardial workload– Decreased level of oxygen in blood delivered to the

myocardium