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Cardiovascular

Cardiovascular. Circulatory System. The circulatory system is composed of: Vessels Fluid Pump Blood flows from systemic to pulmonary to systemic circulation. Heart – Conduction System. Conduction pathway SA node Pacemaker Sinus rhythm AV node Located in the floor of right atrium

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Cardiovascular

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  1. Cardiovascular

  2. Circulatory System The circulatory system is composed of: Vessels Fluid Pump Blood flows from systemic to pulmonary to systemic circulation.

  3. Heart – Conduction System • Conduction pathway • SA node • Pacemaker • Sinus rhythm • AV node • Located in the floor of right atrium • AV bundle (bundle of His) • Right and left branches • Purkinje fibers • Terminal fibers

  4. Heart – Conduction System (Cont’d) • Electrocardiogram (EKG) • P wave • Depolarization of atria • QRS wave • Depolarization of ventricles • T wave • Repolarization of ventricles

  5. Factors that Increase Heart Rate • Increased thyroid hormones or epinephrine • Elevated body temperature, infection • i.e., Fever • Increased environmental temperature • Especially in high humidity • Exertion or exercise • Smoking • Stress response • Pregnancy • Pain

  6. Coronary Circulation • Right and left coronary arteries • Branch of the aorta immediately distal to aortic valve • Part of the systemic circulation • Left coronary artery divides into

  7. Coronary Circulation (Cont’d) • Right coronary artery branches

  8. Cardiac Cycle • Diastole • Relaxation - filling chambers • Systole • Contraction provides pressure to eject blood

  9. Cardiac Cycle (Cont’d)

  10. Heart Sounds • “Lubb-dubb” • “Lubb” – closure of AV valves • “Dubb” – closure of semilunar valves • Murmurs • Caused by faulty valves • Pulse • Indicates heart rate

  11. Pulse Points

  12. Cardiac Function • Preload • Amount of blood delivered to heart by venous return • Afterload • Force required to eject blood from ventricles • Determined by peripheral resistance in arteries

  13. Stroke volume (SV) • Volume of blood pumped out of ventricle/contraction • Cardiac output (CO) • Blood ejected by a ventricle in one minute • CO = SV × HR (heart rate)

  14. Cardiac Output

  15. Blood Vessels • Arteries – arterioles • Transport blood away from heart • Veins – venules • Bring blood back to the heart • Capillaries • Microcirculation within tissues • Systemic circulation • Exchange of gases, nutrients, and wastes in tissues • Pulmonary circulation • Gas exchange in lungs

  16. Blood Pressure • Systolic pressure • Exerted when blood is ejected from ventricles (high) • Diastolic pressure • Sustained pressure when ventricles relax (lower) • Blood pressure (BP) is altered by cardiac output, blood volume, and peripheral resistance to blood flow.

  17. Blood Pressure (Cont’d) Changes in blood pressure Sympathetic branch of Autonomic Nervous System Increased output → vasoconstriction and increased BP Decreased output → vasodilation and decreased BP BP is directly proportional to blood volume. Hormones Antidiuretic hormone (↑ BP); aldosterone (↑ blood volume, ↑ BP); renin-angiotensin-aldosterone (vasoconstriction ↑ BP)

  18. Blood Pressure (Cont’d)

  19. Heart Disorders

  20. Diagnostic Tests for Cardiovascular Function • ECG • Useful in the initial diagnosis and monitoring of dysrhythmias, myocardial infarction, infection, pericarditis • Ausculation • Detection of valvular abnormalities or abnormal shunts of blood that cause murmors • Echocardiography • Used to record the heart valve movements, blood flow, and cardiac output • Exercise stress tests • To assess general cardiovascular function

  21. Diagnostic Tests for Cardiovascular Function • Chest x-ray films • Used to show shape and size of the heart • Nuclear imaging • Tomographic studies • Cardiac catheterization • Measure pressure and assess valve and heart function • Determination of central venous pressure and pulmonary capillary wedge pressure • Angiography • Visualization of blood flow in the coronary arteries

  22. Diagnostic Tests for Cardiovascular Function • Doppler studies • Assess blood flow in peripheral vessels • Records sounds of blood flow or obstruction • Blood tests • Assess serum triglycerides, cholesterol levels, levels of sodium, potassium, calcium, other electrolytes • Arterial blood gas determination • Check the current oxygen level and acid-base balance

  23. General Treatment Measures for Cardiac Disorders • Dietary modifications • Decrease total fat intake • General weight reduction • Reduce salt intake • Regular exercise program • Increases high-density lipoprotein • Lowers serum lipid levels • Reduces stress levels • Cessation of smoking • Decreases risk of coronary disease

  24. General Treatment Measures for Cardiac Disorders – Drug Therapy • Vasodilators • Reduction of peripheral resistance • Beta-blockers • Treatment of hypertension and dysrhythmias • Reduction of angina attacks • Calcium channel blockers • Decrease cardiac contractility • Antihypertensive and vasodilator • Prophylactic against angina

  25. General Treatment Measures for Cardiac Disorders – Drug Therapy (Cont’d) • Digoxin • Treatment for heart failure • Antidysrhythmic drug for atrial dysrhythmias • Antihypertensive drugs • Used to lower blood pressure • Adrenergic-blocking drugs • Act on SNS centrally or on the periphery • Angiotensin-converting enzyme (ACE) inhibitors • Block conversion on angiotensin I to angiotensin II

  26. General Treatment Measures for Cardiac Disorders – Drug Therapy (Cont’d) • Diuretics • Remove excess sodium and/or water • Treatment of high BP and congestive heart failure • Anticoagulants • Reduce risk of blood clot formation • Cholesterol-lowering drugs • Reduction of low-density lipoproteins and cholesterol content

  27. Selected Cardiovascular Drugs

  28. Coronary Artery Disease (CAD) or Ischemic Heart Disease (IHD) or Acute Coronary Syndrome

  29. Arteriosclerosis and Atherosclerosis • Arteriosclerosis • General term for all types of arterial changes • Lumen gradually narrows and may become obstructed • Cause of increased BP • Atherosclerosis • Presence of atheromas in large arteries • Plaques consisting of lipids, calcium, and possible clots • Related to diet, exercise, and stress

  30. Normal (top) vs. Atherosclerotic Aorta (bottom)

  31. Lipid Transport • Lipids are transported in combination with proteins. • Low-density lipoprotein (LDL) • Transport of cholesterol from liver to cells • Major factor contributing to atheroma formation • High-density lipoprotein (HDL) • Transport of cholesterol away from the peripheral cells to liver – “good” lipoprotein

  32. Development of an Atheroma

  33. Risk Factors for Atherosclerosis • Non-modifiable • Age • Gender • Genetic or familial factors • Modifiable • Obesity • Sedentary lifestyle • Cigarette smoking • Diabetes mellitus • Poorly controlled hypertension • Oral contraceptives and smoking

  34. Atherosclerosis • Diagnostic tests • Serum lipid levels • Treatment • Weight loss • Increase exercise • Lower total serum cholesterol and LDL levels by dietary modification • Reduce sodium intake • Control hypertension • Cessation of smoking • Anti-lipidemic drugs • Surgical intervention – i.e., coronary artery bypass graft

  35. Coronary Artery Bypass Graft

  36. Angina Pectoris • Occurs when there is a deficit of oxygen to meet myocardial needs • Chest pain may occur in different patterns. • Classic or exertional angina • Variant angina – at rest • Unstable angina • Prolonged pain at rest – may precede myocardial infarction

  37. Angina – Imbalance of Oxygen Supply and Demand

  38. Emergency Treatment for Angina • Rest, stop activity • Seat in an upright position • Nitroglycerin • Vital Signs • Oxygen • Patient known to have angina • Second dose of nitroglycerin • Then 911 • Patient without history of angina - 911

  39. Myocardial Infarction • Coronary artery is obstructed • Atherosclerosis • Thrombus from atheroma may obstruct artery. • Vasospasm is cause in a small percentage. • Size and location of the infarct (lack of oxygen) determine the damage.

  40. Warning Signs of Heart Attack • Feeling of pressure, heaviness, or burning in chest – increased activity • Sudden shortness of breath, weakness, fatigue • Nausea, indigestion • Anxiety and fear • Pain – if present • Substernal • Crushing • Radiating

  41. Myocardial Infarction (Cont’d) • Diagnostic tests • ECG changes • Serum cardiac enzymes and isoenzymes • myosin and cardiac troponin are elevated.

  42. Myocardial Infarction – Complications Sudden death Cardiogenic shock Congestive heart failure Rupture of necrotic heart Tamponade Thromboembolism causing CVA (with left ventricular MI)

  43. Myocardial Infarction – Treatment • Reduce cardiac demand • Oxygen therapy • Analgesics • Anticoagulants • Thrombolytic agents may be used. • Tissue plasminogen activator • Medication to treat • Dysrhythmias, hypertension, congestive heart failure • Cardiac rehabilitation begins immediately.

  44. Conduction System in the Heart

  45. Cardiac Arrest • Cessation of all heart activity • No conduction of impulses • Flat ECG • Many reasons • Excessive vagal nerve stimulation • Potassium imbalance • Cardiogenic shock • Drug toxicity • Insufficient oxygen • Respiratory arrest • Blow to heart

  46. Congestive Heart Failure • Heart is unable to pump out sufficient blood to meet metabolic demands of the body. • Usually a complication of another cardiopulmonary condition • May involve a combination of factors • Various compensation mechanisms maintain cardiac output. • Some of these often aggravate the condition.

  47. Congestive Heart Failure (Cont’d) • When heart cannot maintain pumping capability • Cardiac output or stroke volume decreases • Less blood reaches the various organs • Decreased cell function • Fatigue and lethargy • Mild acidosis develops • Backup and congestion develop as coronary demands for oxygen and glucose are not met. • Output from ventricle is less than the inflow of blood. • Congestion in venous circulation draining into the affected side of the heart

  48. Effects of Congestive Heart Failure Left-sided congestive heart failure

  49. Effects of Congestive Heart Failure (Cont’d) Right-sided congestive heart failure

  50. Signs and Symptoms of Congestive Heart Failure • Forward effects (similar with failure on either side) • Decreased blood supply to tissues, general hypoxia • Fatigue and weakness • Dyspnea and shortness of breath • Compensation mechanisms • Tachycardia • Cutaneous and visceral vasoconstriction • Daytime oliguria

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