Ischemic Heart Disease

1. Ischemic Heart Disease Dr. Fletcher. Week 3/ CVS module 9-11-2003

2. Ischemia heart disease • Restriction of blood supply, relative to demands of the heart. • Ischein = to restrict. Recall: • Heart has high : - Work load. - Metabolic Rate. - Aerobic metabolism. - Oxygen demands.

3. Features of Ischemia heart disease : • Coronary Obstruction. • Cardiac Pain. • Cardiac Ischemia lesions.

4. 1) Coronary Obstruction: • Obstruction of coronary arteries  decrease blood to heart.

5. 2) Cardiac Pain: Common Characteristics : • Sever pain  gripping, crushing, arresting. • Chest  “Retrosternal”, behind the sternum • Radiating to left arm, neck and jaw.

6. Coronary obstruction/Cardiac pain/Cardiac Ischemia lesion Obstruction: Impediment. Stenosis  Narrowing of blood vessle Pain : Angina Pectoris Cardiac lesions Ischemia fibrosis. Narrow lumen I) Obstruction II) Occlusion Cardiac lesions Infarct (necrosis). Pain : Infarct Pain Occlusion: Closed vessel Closure of the lumen

7. I) Stenosis: • It is narrowing without complete closure  this is a gradual process. • As a result of slow gradual changes  it will give chance for adaptation by forming anastomosis ( other area feed the Ischemic area) Partial Ischemia. • Lesions: Occasional cell atrophy. It is not a vacuum, because fibrous tissue replace the space ( Fibrosis intravenous).

8. Pain Angina Pectoris: • General chest pain. • Its specific characteristic are: 1) Induced by exertion. 2)Paroxysmal (~ 15 minutes) (to differentiate between it and other chest pain). 3) Relieved by rest. 4) Relieved by Nitroglycerin  vasodilatations.

9. II) Occlusion: • Sudden onset ( due to thrombosis, plaque rupture) • Complete Ischemia to the area of heart. • Give area of infarction sizable.

10. Pain of infarct type: (Important for distinguishing) 1) Very sever. 2) Prolonged pain - at least 30 min (not 15 min) - often 1 hours. - Some cases 6 hrs ( have to be controlled byopiates). 3) Not induced by exertion. 4) Not relieved by rest. 5) Not relieved by nitroglycerin.

11. 3) Cardiac Lesions: • Ventricle lesions ( 97%). • Right ventricle lesion  extensions in the left or septal.

12. 1. Functional disruption of the heart:  Arrhythmia due to Ischemia ( local) of conducting system.  it can be picked up by ECG  & might end up with sudden death.

13. 2. Diffuse ischemic fibrosis: • It is Patchy muscle fiber atrophy • There is a replacement fibrosis ( strengthens). • Post Mortem examination: We see – Grayish-white sheen. - ill defined  Vague

14. 3. Infarction: due to Occlusion • Post mortem Features : • Inapparent until >18 hrs survival. • They become Apparent after 24 hrs. • Infarct site are Yellow due to Autolysis at 37C (viable muscle). • When tissue necrosis occur • The tissue release many substances such as LDH, CPK and Troponin • Induce inflammatory reaction  migration of neutrophils to the site of necrosis and Increase phagocytosis. • Electrolyte imbalance (increase Na and decrease K)

15. Summary: Angina vs. MI

16. Sudden Death: Causes: 1) Arrhythmia  Ventricular fibrillation. 2) Ischemia : a) re-entrant circuit b) damaged conducting system, coronary lesions (hard to find). 3) Massive Acute infarct: infarct is not visible but coronary thrombosis easily found.