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Chapter 35

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Chapter 35

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  1. Chapter 35 Cardiac Disorders

  2. Learning Objectives • Label the major parts of the heart. • Describe the flow of blood through the heart and coronary vessels. • Name the elements of the heart’s conduction system. • State the order in which normal impulses are conducted through the heart. • Explain the nursing considerations for patients having procedures to detect or evaluate cardiac disorders.

  3. Learning Objectives • Identify nursing implications for common therapeutic measures, including drug, diet, or oxygen therapy; pacemakers and cardioverters; cardiac surgery; and cardiopulmonary resuscitation. • Explain the pathophysiology, risk factors, signs and symptoms, complications, and treatment for selected cardiac disorders. • List the data to be obtained in assessing the patient with a cardiac disorder. • Assist in developing nursing care plans for patients with cardiac disorders.

  4. Anatomy and Physiology of the Heart

  5. Anatomy Chambers Two upper atria (right and left) Two lower ventricles (right and left) Muscle layers Endocardium, myocardium, and epicardium Valves Atrioventricular valves Mitral and tricuspid Semilunar valves Aortic and pulmonic

  6. Heart Sounds The first heart sound (S1), referred to as lub, occurs when the ventricles contract during systole and when the mitral and tricuspid valves close The second heart sound (S2), called dub, occurs during ventricular relaxation or diastole and is caused by the closing of the aortic and pulmonic valves

  7. Figure 35-1

  8. Coronary Blood Flow Left coronary artery and the right coronary artery Left coronary artery branches into the left anterior descending and circumflex arteries Right coronary artery branches to supply the sinoatrial (SA) and the atrioventricular (AV) nodes, the RA and RV, and the inferior part of the LV

  9. Coronary Blood Flow Venous system parallels the arterial system: the great cardiac vein follows the left anterior descending artery and the small cardiac vein follows right coronary artery Veins meet to form the coronary sinus (largest coronary vein), which returns deoxygenated blood from the myocardium to the right atrium

  10. Figure 35-2

  11. Figure 35-3

  12. Conduction SA node, called the pacemaker, initiates the impulse The impulse is carried throughout the atria to the AV node, located on the floor of the RA Impulse is delayed in the AV node, then transmitted to the ventricles through the bundle of His The bundle is made up of Purkinje cells and is located where the atrial and ventricular septa meet Bundle of His divides into left and right bundle branches Left branch divides into anterior and posterior branches: fascicles Terminal ends of right and left branches: the Purkinje fibers When impulse reaches Purkinje fibers, ventricles contract

  13. Figure 35-4

  14. Conduction Cardiac innervation Heart innervated by sympathetic and parasympathetic fibers of the autonomic nervous system Sympathetic fibers distributed throughout the heart Sympathetic stimulation results in increased heart rate, increased speed of conduction through the AV node, and more forceful contractions Parasympathetic fibers (part of the vagus nerve) found primarily in the SA and AV nodes and the atrial tissue Parasympathetic stimulation results in slowing of heart rate, slowing of conduction through the AV node, and decreased strength of contraction

  15. Cardiac Function Cardiac cycle Contraction and relaxation of the heart make up one heartbeat Cardiac output Amount of blood (in liters) ejected per minute Factors that affect stroke volume: preload, contractility, and afterload Myocardial oxygen consumption Myocardial tissue routinely needs 70% to 75% of the oxygen delivered to it by the coronary arteries

  16. Age-Related Changes Heart Increased density of connective tissue and decreased elasticity Number of pacemaker cells in the SA node decreases, as does the number of nerve fibers in the ventricles Blood vessels The number of pacemaker cells in the SA node decreases, as does the number of nerve fibers in the ventricles

  17. Nursing Assessment of Cardiac Function

  18. Chief Complaint and History of Present Illness Symptoms related to cardiac disorders include fatigue, edema, palpitations, dyspnea, and pain Note when symptoms occur, what aggravates them, and what relieves them

  19. Medical History Hypertension, kidney disease, pulmonary disease, stroke, rheumatic fever, streptococcal sore throat, and scarlet fever Document previous cardiac disorders and hospitalizations. List recent and current medications and note allergies in appropriate records

  20. Family History Assess whether immediate relatives have had hypertension, coronary artery disease (CAD), other cardiac disorders, or diabetes mellitus

  21. Review of Systems Systematically assess whether the patient has experienced the following: weight gain, fatigue, dyspnea (shortness of breath), cough, orthopnea (difficulty breathing in a supine position), paroxysmal nocturnal dyspnea (sudden dyspnea during sleep), palpitations, chest pain, syncope (fainting), concentrated urine, or leg edema

  22. Functional Assessment Determine how this illness has affected the patient’s ability to carry out usual activities Activity and rest patterns and usual diet Ask about sources of stress and coping strategies

  23. Physical Examination Vital signs Blood pressure, pulses, and respirations Skin Heart sounds Heart murmurs Extremities

  24. Figure 35-5

  25. Diagnostic Tests and Procedures Electrocardiogram (ECG) Ambulatory ECG (Holter monitor) Implantable loop monitor/recorder (ILR) Echocardiogram (heart sonogram) Transesophageal echocardiogram (TEE) Magnetic resonance imaging (MRI) Multiple-gated acquisition scan

  26. Diagnostic Tests and Procedures Stress test (exercise tolerance test) Perfusion imaging Thallium imaging Ultrafast computed tomography Cardiac catheterization Electrophysiology study (EPS)

  27. Figure 35-6

  28. Laboratory Tests Arterial blood gases Pulse oximetry Cardiac enzymes Creatine phosphokinase Cardiac protein markers Complete blood count Lipid profile B-type natriuretic peptide (BNP) C-reactive protein (CRP)

  29. Figure 35-7

  30. Drug Therapy Cardiac glycosides Antianginals Antidysrhythmics Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) Diuretics Anticoagulants

  31. Drug Therapy Heparin Low-molecular-weight heparin (LMWH) Warfarin Antiplatelet agents Fibrinolytic agents (also called thrombolytics) Lipid-lowering agents Analgesics

  32. Diet Therapy Low-fat, high-fiber diet Well-balanced diet Emphasis on fruits, vegetables, grains, and proteins low in fat (fish, legumes, poultry, lean meats) Cholesterol intake should be limited to 200 mg/day; foods with trans fatty acids, limited to 8 Exercise program may help achieve optimal weight

  33. Diet Therapy Sodium A diet containing sodium 2 g/day most often prescribed Potassium Patients taking potassium-wasting diuretics need adequate potassium in the diet

  34. Other Therapeutic Measures Oxygen therapy Pacemakers Temporary Permanent Cardioversion

  35. Cardiac Surgery Common surgical procedures Pacemaker insertion Repair or replace valves or septa or remove tumors Coronary artery bypass surgery

  36. Cardiac Surgery Preoperative nursing care Interventions Fear and Anxiety

  37. Cardiac Surgery Postoperative nursing care Interventions Ineffective Breathing Pattern Pain Ineffective Thermoregulation Decreased Cardiac Output Risk for Infection Anxiety

  38. Cardiac Disorders

  39. Coronary Artery Disease (CAD) Arteriosclerosis Abnormal thickening, hardening, loss of elasticity of arterial walls Atherosclerosis Form of arteriosclerosis; inflammatory disease that begins with endothelial injury and progresses to the complicated lesion seen in advanced stages of the disease process Progression of lesions Fatty streak Fibrous plaque Complicated lesions Collateral circulation Branches grow from existing arteries; provide increased blood flow

  40. Coronary Artery Disease (CAD) Risk factors Nonmodifiable Age, gender, heredity, and race Modifiable Increased serum lipids, high blood pressure, cigarette smoking (nicotine), diabetes mellitus with elevated blood glucose, obesity, sedentary lifestyle Other factors Stress, sex hormones, birth control pills, excessive alcohol intake, high homocysteine levels

  41. Angina Pectoris The most common symptom of CAD Demand for oxygen by myocardial cells exceeds supply Stable angina Occurs with exercise or activity and usually subsides with rest Unstable angina Pain more severe, occurs at rest or with minimal exertion, is often not relieved by NTG or requires more frequent NTG administration, and is not predictable Variant angina Caused by coronary artery spasm; may not be associated with CAD Unpredictable and often occurs at rest

  42. Angina Pectoris Medical treatment Initial therapy for patients with angina A Aspirin and antianginal therapy B Beta-blocker and blood pressure C Cigarette smoking and cholesterol D Diet and diabetes E Education and exercise

  43. Acute Myocardial Infarction Risk factors for AMI Obesity, smoking, a high-fat diet, hypertension, family history, male gender, diabetes mellitus, sedentary lifestyle, and excessive stress

  44. Acute Myocardial Infarction Pathophysiology Begins with occlusion of a coronary artery Over 4-6 hours, ischemia, injury, infarction develop Ischemia results from a lack of blood and oxygen to a portion of the heart muscle If ischemia is not reversed, injury occurs Deprived of blood and oxygen, the affected tissue becomes soft and loses its normal color Continued ischemia: infarction of myocardial tissue Ischemia lasting 20 minutes or more is sufficient to produce irreversible tissue damage

  45. Acute Myocardial Infarction Complications Heart failure, cardiogenic shock, thromboembolism, and ventricular aneurysm/rupture Signs and symptoms Pain Heavy or constrictive pain located below or behind sternum May radiate to the arms, back, neck, or jaw Patient becomes diaphoretic and lightheaded and may experience nausea, vomiting, and dyspnea The skin is frequently cold and clammy Patient experiences great anxiety; feeling of impending doom

  46. Acute Myocardial Infarction Medical diagnosis History and the physical signs and symptoms Laboratory evidence and ECG changes Cardiac markers Troponin, myoglobin, and cardiac enzymes Electrocardiogram Ischemia: ST segment depressed; T wave is inverted If there has been total occlusion of a coronary artery, the ECG will show ST elevation (STEMI) Following infarction, another change often seen on the ECG waveforms is a significant Q wave

  47. Figure 35-8

  48. Acute Myocardial Infarction Medical treatment Drug therapy Sublingual or intravenous nitroglycerin Morphine or Demerol Oxygen Fibrinolytic therapy Aspirin and beta-adrenergic blockers Percutaneous coronary intervention (PCI) Intracoronary stents Coronary atherectomy Laser angioplasty Radiation therapy Coronary artery bypass graft surgery

  49. Figure 35-9

  50. Figure 35-10