Coronary Artery System An MI in this left coronary artery system is likely to produce more extensive damage because the left system covers more territory than the right LAD RCA LCA CX
Clinical Correlations of Myocardial Infarction • In patients with extensive myocardial injury, coronary blood flow diminishes as cardiac output declines and heart rate accelerates • Because coronary artery disease is usually generalized or diffuse, ischemia that occurs at a distance from the infracted segment may result in a vicious cycle in which a stuttering and expanding myocardial infarction ultimately leads to profound Left Ventrivular failure, hypotension, and cardiogenic shock Medscape.com
Symptoms of Myocardial Infarction (1) • Fatigue • Malaise and pale • Chest discomfort – recurrent pain may be the earliest symptom, triggered by exertion and relieved by rest ▫ Intense and unremitting for 30-60 minutes ▫ Chest Pain: squeezing, aching, burning, or sharp ▫ Retrosternal and radiating up to the neck, shoulder, jaw and down the ulnar aspect of the left arm ▫ Atypical pain in elderly patients, women and diabetic patients Medscape.com
• May present as a feeling of indigestion, fullness or gas • Anxiety • Light-headedness with or without syncope • Cough and wheezing or SOB • Nausea with or without vomiting • Diaphoresis Medscape.com Symptoms of Myocardial Infarction (2)
- content/uploads/2013/11/ early-signs-of-a-heart- attack.jpg Radiation of Chest Pain in Myocardial Infarctions
Signs of Myocardial Infarction (1) • Increased Heart Rate causes Irregular Pulse • Blood Pressure is initially high because of peripheral arterial vasoconstriction resulting from an adrenergic response to pain and ventricular dysfunction ▫ HYPERTENSION may precipitate MI ▫ HYPOTENSION is seen with right ventricular MI or severe left ventricular dysfunctions • Jugular Venous (Neck Vein) Distention: sign of Right Ventricular failure Medscape.com
• Coughing, Wheezing (rales) and production of Frothy Sputum • Fever (>102 F) present within 24-48 hours ▫ Temperature curve is parallel to elevations of creatine kinase CK-MB isoenzyme (mainly found in cardiac muscle tissues) Increases 3-12 hours at the onset of chest pain, Peaks at 24 hours and Returns to the baseline after 48-72 hours • Peripheral Cyanosis • Edema Medscape.com Signs of Myocardial Infarction (2)
Risk Factors: Ischemic Heart Disease (1) • AGE- Men over 45 or women over 55 • DIET- Diets high in salt, fat and high (LDL) cholesterol • TOBACCO- Smoking and long-term exposure to second hand smoke allows cholesterol deposits to collect in arteries • HIGH BP- Damages the coronary arteries by accelerating atherosclerosis • HIGH CHOLESTEROL/TRIGLYCERIDE LEVELS- Major parts of deposits that lead to arterial stenosis (High LDL = BAD!; High HDL= GOOD!) • DIABETES- Especially uncontrolled diabetes • FAMILY HISTORY- You have an increased risk Medscape.com
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