Cardiovascular System Biomedicine Review

1. Cardiovascular System Biomedicine Review • Felix Hernandez, M.D.

2. Normal Heart

3. Chambers of the Heart

4. The Peripheral Vascular System

5. Blood Pressure • Blood pressure is regulated by cardiac output and peripheral vascular resistance • Systolic Blood Pressure • the blood pressure measured during the period of ventricular contraction • In a blood pressure reading, it is the higher of the two measurements. • Diastolic Blood Pressure • the minimum level of blood pressure measured between contractions of the heart. • Can vary with age, gender, weight and emotional state.

6. Hypertension • Primary Hypertension • elevated blood pressure without a known causative factor • this is the most common type • causes: • genetic predisposition and obesity • stress, increased alcohol intake • diabetes, sodium and water retention • Secondary Hypertension • elevated blood pressure with an identifiable cause • Causes: • renal artery stenosis, congenital heart defects, cushing’s syndrome, sleep apnea, pregnancy, stimulants

7. Risk Factors

8. Hypertension • Signs and Symptoms • no initial symptoms usually occur • chronic fatigue • headache • dizziness • dyspnea • chest pain and palpitations

9. Treatment • ABC • A: ACE Inhibitor • Enalapril (Vasotec), Lisinopril (Zestril) • block the conversion of angiotensin I to angiotensin II which would normaly act as a vasoconstrictor • this blocking causes vasodilation which will cause a decrease in resistance and a decrease in BP • B: Beta Blocker • Action: blocks the beta adrenergic receptors of the sympathetic nervous system which results in vasodilation and a decrease in the release of renin • Contraindications: Pregnancy and Lactation • Cautions: asthma, diabetes • Side Effects: Hypotension, bradycardia, wheezing, dyspnea • C: Calcium Chanel Blocker • Amlodipine (Norvasc), Diltiazem (Cardizem), Nifedipine (Procardia) • block calcium influx into the beta receptors which causes a decrease in the force of contraction and reduces the heart rate

10. Specific Side Effects of Beta Blockers • Propranolol (Inderal) • bradycardia, CHF, impotence • Atenolol (Tenormin) • dizziness, fatigue, cold extremities, depression, impotence • Timolol (Blocarden) • fatigue, bradycardia, extremity pain, impotence • Metoprolol (Lopressor) • fatigue, dizziness, depression, confusion, short term memory loss, headache, impotence

11. Treatment • Diuretics • Loop Diuretics • Furosemide (Lasix) • inhibit the reabsorption of sodium and chloride in the ascending loop of Henle • Thiazide Diuretics • Hydrochlorothiazide • inhibit sodium and chloride reabsorption in the the distal tubules • Used to treat hypertension and edema • Contraindications: hypersensitivity to sulfonamides, anuria, oliguria, fluid and electrolyte depletion • Side Effects: tiredness, weakness, dizziness, orthostatic hypotension, tinnitus

12. Treatment • Potassium Sparring Diuretic • Spironolactone (Aldactone) • MOA: Antagonist of Aldosterone • Side Effects: Hyperkalemia, glucose intolerance in DM patients

13. Unstable Angina • an anginal attack occurring at rest or increasing in frequency • caused by blockage of the coronary arteries • has a high risk of subsequent myocardial infarction • Labs: is evaluated with EKG. First you do a resting EKG, if that comes back normal then you perform an exercise stress test.

14. Treatment • Nitroglycerin • Uses: Relief of anginal pain and to suppress tachycardia • MOA: relaxes vasculature (both arteries and veins but mostly veins) causing a decreased in preload and afterload • Contraindications: hypersensitivity, severe anemia, head trauma or cerebral hemorrhage • Side Effects: orthostatic hypotension, dry mouth, blurred vision, tachycardia, headache

15. Myocardial Infarction • Is the leading cause of death • caused by an obstruction of a coronary artery • S/S: chest pain that lasts for more than 30 minutes and radiates to the left arm. The pain is not relieved by nitroglycerin • Labs: Increased Troponin and CK-MB • EKG Changes: T-wave inversion, ST elevation, Q-wave formation • Treatment: Oxygen, aspirin, morphine, beta-blocker, ARB

16. Ventricular Fibrillation • Dangerous electrical dysfunction • Commonly associated with MI, CHF and shock • EKG: rapid, chaotic, and distorted • S/S: cheat pain, SOB, sudden death • Tx: Direct Current Cardioversion

17. Ventricular Flutter • Heart rate of 150-350 BPM • Associated with hypoxia or ischemic insults • S/S: hypotension and sudden death • EKG: loss of normal QRS morphology • Tx: defibrillation

18. Atrial Fibrillation • Uncoordinated rapid contractions of the atria • S/S: dizziness, papitations, irregularly irregular pulse • associated with the development of thrombi that can embolize • Tx: Warfarin (Coumadin), anti-arrhythmics

19. Renal Artery Stenosis • Caused by fibromuscular dysplasia in young women and atherosclerosis in older men • S/S: HTN, audible abdominal bruit, high renin levels • Tx: ACE, angioplasty

20. Hypothermia • A decrease in body temperature • S/S: decreased peripheral perfusion, decreased respiratory rate, decreased bowel sounds, decreased DTR • Can also cause arrhythmia, bradycardia and hypotension

21. Deep Vein Thrombosis • Development of a blood clot in the deep veins of the lower extremity • Associated with cancer, estrogen therapy, and prolonged immobility • Virchow’s Triad: hypercoagulability, venostasis, endothelial injury • S/S: Homan’s Sign --> pain on foot dorsiflexion • Tx: Heparin (works faster so it is used initially) and Warfarin (Coumadin) • Prothrombin Time (PT) is used to measure the effects of Warfarin

22. Cholesterol • Total Cholesterol • desired levels is <200 • >240 is considered high risk • HDL • desired level is >60 • considered protective against heart disease • levels are increase by: vigorous exercise, insulin, estrogens • levels are decreased by starvation, obesity, hypothyroidism, smoking, DM and liver disease • LDL • desired level <100 • >190 gives you the highest increased risk of heart disease • Levels are increased by atherosclerosis, CHD • Levels are decreased by depression, anxiety

23. Cholesterol Lowering Drugs • Cholestyramine • MOA: forms insoluble complexes with bile salts allowing them to be excreted in feces. The body compensates by increasing the number of LDL receptors and oxidizing cholesterol to bile acids • Indications: LDL>190 or 160 with 2 risk factors • Lipid Profile Effects: • decreases TC, and LDL • Increases Triglycerides, VLDL and HDL

24. Cholesterol Lowering Drugs • MOA: inhibit HMG-CoA reductase in the liver which is the enzyme that catalyzes the rate limiting step in cholesterol synthesis. • Profile Changes: • Decreases TC, LDL, VLDL and Triglycerides • Increases HDL • Side Effects: Myalgia • Drugs: • Simvastatin (Zocor) • Atorvastatin (Lipitor) • Rosuvastatin (Crestor)

25. Chronic Congestive Heart Disease

26. Chronic Congestive Heart Disease

27. Digitalis • MOA: inhibits the Na-K ATPase which alters the mechanical and electrical actions of the heart and causes an increase in myocardial contractility • Uses: Heart Failure (improves CO) and atrial fibrillation • Contraindications: hypersensitivity, ventricular tachycardia • Side Effects: dizziness, muscle weakness, visual disturbances, hypokalemia, bradycardia, arrhythmia

28. Cardiomyopathy • Dilated—viral infection, alcohol, cardiotoxic drugs • Ventricles are dilated and the myocardium is flabby and thinned • Hypertrophic—genetic • Thickening of LV myocardium • Mutation in the genes that code for myocardium constrictive proteins • Restrictive—amyloidosis, endomyocardial fibrosis • Heart cant expand to receive inflowing blood • Heart transplant is the only treatment

29. Leukocytes • Granulocytes • Basophil: allergic and histamine reactions • Eosinophil: parasitic infection, fungal infection • Neutrophil: bacterial infection, inflammation, stress (Not Viral) • Agranulocytes • Lymphocyte: viral infection, chronic infection • Monocyte: chronic infection

30. White Blood Cell Count • Increased by: • acute infection, neoplasm, leukemia • Decreased by: • bone marrow malfunction, immune deficiency, iron deficiency, AIDS, chemotherapy

31. Immunoglobulins • IgG: most predominant, can cross the placenta and pass immunity to the fetus • IgM: is the first to appear • IgA: secretory antibody, is found in colostrum, secretions, saliva, tears • IgE: least predominant, promotes histamine allergic reactions • IgD: serves as a receptor on B-cells

32. Anemia • General Causes: • chemo, GI bleed, rheumatoid arthritis, Lupus, AIDS, Cancer • S/S: decreased hemoglobin, decreased hematocrit, changes in fingernail beds, pale skin, fatigue • Specific Types: • Aplastic anemia: caused by damage to the bone marrow from toxic chemicals or radiation • Hemolytic Anemia: destruction of red blood cells by toxic chemicals or antibodies • Iron Deficiency Anemia: caused by a dietary lack of iron which leads to deficient hemoglobin synthesis • Pernicious Anemia: caused by an inability to absorb B12 which leads to immature RBCs • Sickle Cell Disease: caused by a defective gene leading to sickle shaped RBCs • Thalassemia: caused by a defective gene which causes the formation of abnormal hemoglobin and a shortened lifespan of RBCs

33. Blood Labs • Red Blood Cell Count (RBC) • increased in: polycythemia, renal disease, pulmonary disease • decreased in: anemia, Hodgkin’s leukemia, sickle cell disease • Hemoglobin and Hematocrit • Increased by: dehydration, shock, COPD, CHF, polycythemia • Decreased by: anemia, leukemia, hyperthyroidism, cirrhosis, massive trauma • Iron • Increased by: acute hepatitis, nephrosis • Decreased by: anemia, lupus, RA, hypothyroidism, 3rd trimester of pregnancy

34. Aspirin • MOA: inhibits cyclooxygenase which is required for prostaglandin synthesis. • Decreases inflammation and pyrogen-induced fever • Decreases pain caused by injury or inflammation • Prevents platelet aggregation • Indications: symptomatic relief of minor main, inflammation, fever or RA. Reduction of stroke risk. • Side Effects: GI upset and bleeding, allergic reaction. • Increased risk of Reye’s Syndrome in children • Occurs when giving aspirin after an infection. Can cause brain, liver and kidney damage with possible death • Overdose is called salicylism and involves tinnitus, dizziness, HA, fever, mental status changes, hyperventilation, and respiratory alkalosis which can lead to a metabolic acidosis • Contraindications: bleeding disorders and peptic ulcer disease

35. Quiz Next Week • 25 questions • 20 Cardiovascular • 5 Musculoskeletal • 2 bone diagrams • 3 multiple choice on muscles (action, innervation, special notes)