Ischemic Heart Disease

1. Ischemic Heart Disease • Group of diseases • Most common cause of death in developed countries • Terminology: • Angina pectoris • Myocardial infarction • Sudden cardiac death • Chronic ischemic heart disease • Coronary artery disease • Acute coronary disease

3. Ischemic Heart Disease • Common in older adults: • >60 in males • >70 in females • M>F • Fisk factors: hypertension, Diabetes, smoking, high cholesterol, genetic factors • Factors reducing the risk: regular exercise, alcohol.

4. Ischemic Heart Disease • Pathogenesis: • Atherosclerosis of coronary arteries • Stenosis (narrowing) of the lumen • Mild, moderate, sever “critical” >75% stenosis • Changes in atheromatous plaques: • Acute plaque change: • fissuring, hemorrhage, rupture with embolism • Usually occurs in moderate stenosis • How does it occur? • Metalloproteinase from macrophages, T-cell activation, hemodynamic trauma

5. Ischemic Heart Disease • Pathogenesis: • Changes in atheromatous plaques: 2. Coronary artery thrombosis • Complete occlusion resulting in infarction • Incomplete occlusion resulting in unstable angina • Embolization 3. Coronary artery vasospasm • Other pathology: • Emboli from aorta or valves • vasculitis • Severe hypotension • Left ventricular hypertrophy

6. Angina Pectoris • Intermittent chest pain caused by transient reversible myocardial ischemia • Typical “stable” angina • Episodic chest pain • Crushing sub-sternal • Radiate to left arm • Due to fixed atherosclerotic narrowing • Usually with critical stenosis >75% • Relieved by rest or nitroglycerin

7. Angina Pectoris • Intermittent chest pain caused by transient reversible myocardial ischemia 2. Prinzmetal (variant) angina: • Occurs at rest, awaken the patient from sleep • Due to coronary artery spasm 3. Unstable angina: • Increase in frequency of angina • With less and less exercise • Last longer • Due to acute changes in atheromatous plaque or thrombosis

8. Myocardial Infarction • Myocardial necrosis caused by local ischemia • In the US 1.5 million cases with 500,000 deaths per year • Age group 45-54 year, M:F 4:1

9. Myocardial Infarction • Pathogenesis: • Coronary artery thrombosis • Necrosis of cardiac muscle after 20-30 minutes of complete occlusion • Necrosis begins in the subendothelial zone • Depends on the vessel involved: • Left anterior descending (40-50%): anterior and apical area of the LV with anterior 2/3rd of septum • Right coronary artery (30-40%): posterior and basal area of the LV, posterior 1/3rd of the septum • Circumflex artery: lateral wall of the LV

10. Myocardial Infarction • Morphology: • 12 h: no change • 12-18 h: coagulative necrosis • 18-24 h: neutrophils • 3 days: peak of inflammation • If reperfusion occurs it results in hemorrhage • 4-7 days: well-defined pale region, with macrophages, and fibroblasts • 10 days: granulation tissue • 4 weeks: collagen depsition • 8 weeks: scar

12. Myocardial Infarction • Complications: • Left ventricular failure (60%) • Cardiogenic shock (10%) • Papillary muscle dysfunction/infarction/rupture • Rupture of LV (4-8%) • Mural thrombi (15%) • Ventricular aneurysm • Acute pericarditis

13. Myocardial Infarction • Clinical: • Sever, crushing sub-sternal chest pain • Radiate to neck, jaw, shoulder and left arm • Last for hours • Dyspnea due to pulmonary edema • If large(>40%) leads to cardiogenic shock • “silent” MI in diabetics and elderly • ECG changes • Elevated CK, troponin, LDH • 25% death due to arrhythmia

14. Chronic Ischemic Heart Disease • Development of progressive congestive heart failure as a consequence of long-term ischemia • Usually with Moderate-severe coronary artery stenosis • Pervious MI and scarring • Dilated heart

15. Sudden Cardiac Death • Excluding: homicide, suicide, trauma and toxins • Causes: heart disease, pulmonary embolism, rupture aortic aneurysm, CNS • Ischemic heart disease is the most common cause • Death due to ventricular arrhthmia