Chapter 35 Cardiac Disorders 1.

Chapter 35 Cardiac Disorders 1

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.

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.

Anatomy and Physiology of the Heart
4

Anatomy Chambers Muscle layers Valves 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 What separates the four chambers? Valves separate the atria from the ventricles. 5

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 6

Figure 35-1 7

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 What are collateral arteries? 8

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 9

Figure 35-2 10

Figure 35-3 11

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 For the heart to pump blood through the chambers, nerves must stimulate muscle contractions in an orderly fashion. What is depolarization and repolarization? The SA node normally generates these impulses at a rate between 60 and 100 beats per minute (bpm). The AV node is also capable of generating an impulse if the SA node fails. 12

Figure 35-4 13

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 14

Cardiac Function Cardiac cycle Cardiac output
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 When the ventricles are at rest (relaxation phase), they are filling up with blood coming from the atria; this is called diastole. At the end of diastole, the atria contract to eject blood into the ventricles. Once the ventricles have filled with blood and the electrical impulse has reached the terminal fibers of the conduction system, the ventricles contract and eject blood into the pulmonary artery from the RV and into the aorta from the LV; this is called systole. How many cardiac cycles would there be in a person with a heart beat of 60 bpm? 15

Age-Related Changes Heart Blood vessels
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 Cardiac dysrhythmias are more common in older people but should still be evaluated because they can be dangerous. What commonly happens to the valves in the older adult? 16

Nursing Assessment of Cardiac Function
17

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 18

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 19

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

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 21

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 22

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

Figure 35-5 24

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 25

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

Figure 35-6 27

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) 28

Figure 35-7 29

Drug Therapy Cardiac glycosides Antianginals Antidysrhythmics
Angiotensin-converting enzyme (ACE) inhibitors (ACEIs) Diuretics Anticoagulants The cardiac glycosides slow the heart rate (negative chronotropic effect) and increase the force of myocardial contraction (positive inotropic effect), causing increased stroke volume and cardiac output. Drugs used to treat angina (chest pain related to myocardial ischemia) include nitrates, beta-adrenergic blockers, and calcium channel blockers. Antidysrhythmics work by slowing the rate of impulse conduction, depressing automaticity, or increasing resistance to premature stimulation. ACE inhibitors work against the renin-angiotensin-aldosterone system to dilate arteries and decrease the resistance to blood flow in the arteries. Many patients with heart problems have fluid retention that is treated with diuretics. Anticoagulants are used to prevent clot formation. 30

Drug Therapy Heparin Low-molecular-weight heparin (LMWH) Warfarin
Antiplatelet agents Fibrinolytic agents (also called thrombolytics) Lipid-lowering agents Analgesics Heparin interferes with factor III in the clotting process. The advantages of using LMWH are that the anticoagulant effect is more predictable. Antiplatelet therapy is often used after an AMI to prevent additional myocardial infarction and strokes. Fibrinolytic agents act to destroy clots that have already formed. What are examples of fibrinolytics? Lipid-lowering medications are frequently part of the overall treatment plan, along with diet and exercise, for many patients with heart disease. Morphine relieves pain, reduces anxiety, and reduces the workload of the heart by trapping some of the venous blood in the periphery of the body. 31

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 How does the reduction of body weight help the heart? 32

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

Other Therapeutic Measures
Oxygen therapy Pacemakers Temporary Permanent Cardioversion Any patient complaining of chest pain unrelieved by nitroglycerin should have supplemental oxygen administered. What is the purpose of a pacemaker? Cardioversion is the delivery of a synchronized shock to terminate atrial or ventricular tachydysrhythmias (rapid abnormal heart rhythms). 34

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

Cardiac Surgery Preoperative nursing care Interventions
Fear and Anxiety Encourage the patient to identify feelings and then explore the basis of those feelings. Do not assume you know how the patient feels. What important nursing intervention is important to relieve anxiety? 36

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

Cardiac Disorders 38

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 How does arteriosclerosis occur? If plaque formation occurs slowly, collateral circulation may develop. 39

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 What is the focus of patient education in reducing the risk factors for CAD? Healthy People 2010 has set several goals related to serum lipid levels; One of these is to reduce the mean total blood cholesterol in adults from 206 mg/dL to 199 mg/dL. 40

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 What factors may precipitate angina? 41

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 42

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 43

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 What are the two types of AMI? Within 24 hours after an infarction, the healing process begins. By the third day, necrotic tissue has been broken down by enzymes and removed by macrophages. Collateral circulation develops to supply the injured area, and scar tissue begins to form. 44

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 The pain may begin with or without exertion. How may the symptoms in women, older adults, and diabetic patients differ from those in other patients? 45

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 Sublingual or intravenous nitroglycerin is administered to dilate coronary arteries and increase blood flow to the damaged area. Oxygen is administered at 4-6 L/min to assist in oxygenating myocardial tissue to support pumping activity and for repairing damaged tissue. Fibrinolytic therapy is recommended for patients with total occlusion. Beta-adrenergic blockers improve survival rates by decreasing the heart rate, reducing the work of the heart, and lessening the oxygen demand of the myocardium. Why is PCI preferred over bypass surgery? 46

Figure 35-8 47

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 48

Figure 35-9 49

Figure 35-10 50

Figure 35-11 51

Assessment Ask patient to describe the pain, including type, location, duration, and severity Interventions Pain Decreased cardiac output Anxiety Cardiac rehabilitation 52

Heart Failure Etiology and risk factors Two types
Disorders that increase the workload of the heart Disorders that interfere with heart’s pumping ability Patients at risk for HF: those with CAD, AMI, cardiomyopathy, hypertension, COPD, pulmonary hypertension, anemia, disease of the heart valves, and fluid volume overload Approximately 4.9 million Americans have heart failure and more than half a million new cases of heart failure are diagnosed every year. How frequently does heart failure occur after age 65? 53

Heart Failure Pathophysiology Compensation
The LV, RV, or both fail as pumps Usually left side of heart fails first; right side fails as a result of the left-sided failure Compensation Sympathetic compensation Renal compensation Natriuretic peptides Ventricular hypertrophy Heart failure can be classified as systolic HF resulting from ineffective pumping of the ventricles or as diastolic HF resulting from impaired filling of the ventricles. What three mechanisms does compensation occur through? 54

Heart Failure: Signs and Symptoms
Left-sided heart failure Anxious, pale, and tachycardic Consecutive blood pressure readings may show a downward trend Auscultation of the lung fields reveals crackles, wheezes, dyspnea, and cough S3 and S4 heart sounds heard 55

Heart Failure: Signs and Symptoms
Right-sided heart failure Increased central venous pressure, jugular venous distention, abdominal engorgement, and dependent edema Anorexia, nausea, and vomiting from the abdominal engorgement Fatigue, weight gain, decreased urinary output 56

Heart Failure Medical diagnosis
History, physical examination, radiographs, and laboratory test results A chest radiograph may reveal hazy lung fields, distended vasculature, and cardiomegaly. Laboratory tests indicative of HF are decreased serum sodium and Hct from hemodilution and decreased saturated arterial oxygenation from poor pulmonary perfusion. When renal function decreases, what occurs with the BUN and creatinine levels? 57

Heart Failure Medical treatment Drug therapy
ACE inhibitors, diuretics, beta-adrenergic blockers, inotropic agents, cardiac glycosides, and nitrates. In addition, certain patients will benefit from B-type natriuretic peptide Intra-aortic balloon pump (IABP) Ventricular assist devices (VADs) Biventricular pacing Surgery Coronary artery bypass grafting, valve repair or replacement, partial left ventriculectomy, and cardiac transplantation The intra-aortic balloon pump is a temporary device used in the intensive care unit to increase cardiac output and coronary artery perfusion. Biventricular pacing is useful in approximately 30% of HF patients who have conduction delays in the right or left bundle branch. What complications may occur with heart failure? 58

Heart Failure Assessment Heart sounds, rate, and rhythm
Jugular vein distention Baseline respiratory assessment of rate, rhythm, and breath sounds is vital Measure weight and blood pressure accurately Inspect skin and palpate for turgor and edema Intake and output records and daily weights 59

Heart Failure Interventions Decreased Cardiac Output
Impaired Gas Exchange Fluid Volume Excess Activity Intolerance Anxiety 60

Infective Endocarditis
Etiology and risk factors Primarily affect the valves Incidence has decreased with the use of antibiotics, but there has been a resurgence of the problem in intravenous drug abusers Patients with valvular disease also at risk Organisms present in the blood easily colonize valves damaged by rheumatic heart disease or congenital defects, or a mitral valve that is prolapsed. What may increase the risk of a patient having infective endocarditis? 61

Pathophysiology Pathogens, usually bacteria, enter the bloodstream by any of the previously mentioned means The pathogen accumulates on the heart valves and/or the endocardium and forms vegetations 62

Complications Heart failure and embolization Signs and symptoms Fever, chills, malaise, fatigue, and weight loss Chest or abdominal pain; may indicate embolization Petechiae inside the mouth and on the ankles, feet, and antecubital areas Osler’s nodes on the patient’s fingertips or toes 63

Medical diagnosis History, physical examination, results of lab studies Echocardiography Serial blood cultures; elevated WBC Medical treatment Antimicrobials, rest, limitation of activities Prophylactic anticoagulants Surgery to replace an infected prosthetic valve A history of recent dental or surgical procedures may precede IE. What may be revealed with auscultation of heart sounds? Antimicrobials are given intravenously for 2 to 6 weeks, depending on the organism. 64

Assessment Review patient’s history for risk factors, recent invasive procedures, pathologic cardiac conditions, and onset of symptoms Assess for temperature elevation, heart murmur, evidence of HF (cough, peripheral edema), and embolization 65

Interventions Administer prescribed antibiotics Assess cardiac output and monitor for complications Teach patient about the medications prescribed and any restrictions imposed Encourage adequate rest 66

Pericarditis Etiology and risk factors Inflammation of the pericardium
May be primary disease or associated with another inflammatory process The disease may be acute or chronic Acute pericarditis caused by viruses, bacteria, fungi, chemotherapy, or AMI (Dressler’s syndrome) Chronic pericarditis caused by tuberculosis, radiation, or metastases 67

Pericarditis Pathophysiology
In acute pericarditis, inflammatory process increases amount of pericardial fluid and inflammation of the pericardial membranes In chronic pericarditis, scarring of the pericardium fuses the visceral and parietal pericardia together Loss of elasticity results from the scarring Constrictive process prevents adequate ventricular filling 68

Pericarditis Complications Signs and symptoms
Pericardial effusion or accumulation of fluid in the pericardial space May lead to cardiac tamponade Signs and symptoms Chest pain Most severe on inspiration Sharp and stabbing but may be described as dull or burning Relieved by sitting up and leaning forward Dyspnea, chills, and fever 69

Pericarditis Medical diagnosis Medical treatment Serial ECGs
Echocardiogram CPK-MB Blood cultures Medical treatment Analgesics, antipyretics, anti-inflammatory agents, and antibiotics Surgical creation of a pericardial window for chronic pericarditis with effusion How can you differentiate the pain of pericarditis with that of angina? 70

Pericarditis Assessment Interventions
Assessment of heart sounds especially important Interventions Rest and reduction of activity Administer and teach patient about medications Emotional support Vital signs; auscultate for pericardial friction rub Note pain characteristics and response to analgesics and anti-inflammatory agents Monitor the ECG for dysrhythmias 71

Cardiomyopathy Disease of the heart muscle
Cause often unknown; may be secondary to another disease process Usually leads to heart failure Three types: dilated, hypertrophic, and restrictive Risk factors with dilated CMP are excessive use of alcohol, pregnancy, and infections Hypertrophic CMP: common in younger individuals Amyloidosis, sarcoidosis, and other immunosuppressive disorders may predispose individuals to restrictive cardiomyopathy 72

Figure 35-12 73

Cardiomyopathy Pathophysiology
Dilated cardiomyopathy: dilation of the ventricle and severely impaired systolic function Hypertrophic cardiomyopathy: LV hypertrophies and there is thickening of the ventricular septum Restrictive cardiomyopathy: the myocardium becomes rigid and noncompliant What chamber of the heart is most affected by cardiomyopathy? 74

Cardiomyopathy Signs and symptoms
Dilated cardiomyopathy: dyspnea, fatigue, left-sided heart failure, and moderate-to-severe cardiomegaly Hypertrophic cardiomyopathy: dyspnea, orthopnea, angina, fatigue, syncope, palpitations, ankle edema, and S4 sounds Restrictive cardiomyopathy: dyspnea, fatigue, right-sided HF, S3 and S4 sounds, and mitral valve regurgitation 75

Cardiomyopathy Medical diagnosis Echocardiography Chest radiography
An echocardiogram may show thickened ventricular walls and small ventricular cavities. What findings may be revealed with auscultation of heart sounds and with an ECG? 76

Cardiomyopathy Medical treatment
Dilated cardiomyopathy: positive inotropic drugs, diuretics, ACE inhibitors and vasodilators; heart transplant Hypertrophic cardiomyopathy: antidysrhythmics, antibiotics, anticoagulants, calcium channel blockers, beta-blockers; surgical interventions; implantable cardioverter-defibrillator Restrictive cardiomyopathy: similar to that of HF therapy. Heart transplantation may be considered 77

Cardiomyopathy Assessment Interventions Primarily for heart failure
Be alert for dyspnea, cough, edema, dysrhythmias, and decreased cardiac output Interventions Similar to that of patients with HF A hopeful atmosphere and careful explanation of care requirements Encourage the family to support the patient Guide the patient to make lifestyle changes Encourage patient to make decisions and choices 78

Figure 35-13 79

Sudden Cardiac Death When heart activity and respirations cease abruptly Most common reason is coronary heart disease Often preceded by ventricular tachycardia or ventricular fibrillation and occasionally by severe bradydysrhythmias Sudden cardiac death may be the first indication of CAD Other causes: left ventricular dysfunction, cardiomyopathy, hypokalemia, antidysrhythmics, liquid protein diets, and high alcohol consumption Those who survive sudden cardiac death need extensive testing to determine its nature and cause When does the sudden cardiac death event usually occur? 80

Sudden Cardiac Death Implantable cardioverter/defibrillator
For patients with life-threatening recurrent ventricular fibrillation who are unresponsive to medications or pacemakers The device senses heart rate, diagnoses rhythm changes, and treats ventricular dysrhythmias Where is the ICD generator implanted? Patients report that the shocks feel like a blow to the chest. Complications associated with the ICD are inappropriate shocks, broken or displaced leads, and failure to deliver shocks as a result of battery failure or failure to recognize a dysrhythmia. 81

Nursing Care Promote psychosocial adaptation
Body image change and a fear of shocks Patients and families need teaching and support Family instructed in CPR ID bracelet and a card with instructions about the ICD setting carried at all times Advise to avoid strong magnetic fields 82

Valvular Disease Mitral stenosis: narrowing of the opening in the mitral valve that impedes blood flow from the LA into the LV Mitral regurgitation: allows blood to flow back into the LA during diastole Mitral valve prolapse: one or both leaflets enlarges and protrudes into the LA during systole Aortic stenosis: valve cusps become fibrotic and calcify Aortic regurgitation: fibrosis and thickening of the aortic cusps progress until the valve no longer maintains unidirectional blood flow 83

Cardiac Transplantation
The first heart transplantation was performed in 1967 in South Africa by Dr. Christiaan Barnard Today in the United States, approximately 2500 are done annually for end-stage heart disease Donor must meet the criteria for brain death, have no malignancies outside the central nervous system, be free of infection, and not have experienced severe chest trauma 84

Donor and recipient organs carefully matched Recipient must be free of infection at the time of transplantation Patient prepped as any open-heart procedure Cardiopulmonary bypass initiated; recipient’s heart is removed except for the posterior portions of the atria Donor heart trimmed and anastomosed to the remaining native heart Patient removed from bypass, heart restarted, and chest is closed 85

Aftercare similar to that of coronary artery bypass surgery Hemodynamic monitoring, ventilation, cardiac assessment, care of chest tubes, and accurate intake and output measurements are vital Modified protective isolation used Patients and families taught sign/symptoms of infection, to avoid crowds and others with infections Lifelong immunosuppression Rejection monitored by endomyocardial biopsies 86

Electrocardiogram Monitoring
12-lead electrocardiogram Looks at heart from 12 directions or perspectives Permits more precise evaluation of the heart’s electrical activity Continuous ECG monitoring Most units that perform continuous monitoring use the five-lead system with four limb electrodes and a chest electrode What cardiac events occur during the P wave, QRS complex, and the T wave? 87

Figure 35-15 88

Interpretation of electrocardiograms Heart’s electrical activity represented by deflections, positive and negative, from the baseline P wave, QRS complex, and T wave Criteria for interpreting electrocardiograms Rate calculation Rhythm P waves PR interval QRS complex T waves QT interval Dysrhythmias originating in the atria are called atrial dysrhythmias. Dysrhythmias originating in the AV node are called junctional or escape rhythms. Dysrhythmias originating below the AV node are called ventricular. What are impulse blocks? 89

Interpretation of electrocardiograms Normal sinus rhythm The most common cardiac rhythm is sinus in origin because the impulse originates in the SA node; is conducted normally Common dysrhythmias (rhythm disturbance from problem in the conduction system) Atrial dysrhythmias Junctional or escape rhythms Ventricular dysrhythmias 90

Figure 35-17 91

Figure 35-18 92

Figure 35-19 93

Figure 35-20 94

Figure 35-21 95

Figure 35-22 96

Figure 35-23 97

Figure 35-24 98

Figure 35-25 99

Figure 35-26 100

Figure 35-27 101

Figure 35-28 102

Figure 35-29 103

Figure 35-30 104

Hemodynamic Monitoring
Central venous catheter Placed through the skin, into a venous access (brachial, femoral, subclavian, or jugular sites), and threaded into the RA Catheter may have 1 to 3 lumens Mixed venous oxygen saturation The pressure in the RA (called right atrial pressure [RAP] or central venous pressure [CVP]) can be measured. This measurement is used as an indication of fluid volume. What do measurements below normal indicate? Above normal? 105

Pulmonary artery catheter Swan-Ganz catheter Longer than the central venous catheter Inserted like the central venous catheter and is threaded through the RA, tricuspid valve, RV, pulmonic valve, and into pulmonary artery Cardiac output Measured continuously or by thermodilution The purpose of a pulmonary artery catheter is to measure right-sided heart pressures and pulmonary artery pressures and to assess left-sided heart function. What is the normal pulmonary capillary wedge pressure? 106

Arterial line Provides a direct measurement of systolic and diastolic blood pressures Once the line is inserted, it is connected to a pressurized solution to keep the catheter patent and to a transducer to assess pressure. What does the mean arterial pressure indicate? 107

Chapter 35 Cardiac Disorders 1.

Similar presentations

Presentation on theme: "Chapter 35 Cardiac Disorders 1."— Presentation transcript:

Similar presentations

About project

Feedback

Log in

Auth with social network:

Chapter 35 Cardiac Disorders 1.

Similar presentations

Presentation on theme: "Chapter 35 Cardiac Disorders 1."— Presentation transcript:

Similar presentations

About project

Feedback