introducion to cardiovascular system disorder and nursing management .pptx

cardiovascular disorder, medical and nursing management

1. Nursing Managements of Patients With Disorders of the Cardio-Vascular System By Mr. Gedion Zerihun (BSc, MSc in Adult health nursing) Post basic BSc midwifery September, 2024 Mizan-Aman , Ethiopia 10/2/2024 1

2. Content Objective Anatomy and physiology overview Assessment Diagnostic evaluations Cardiovascular disorders

3. Objectives By the end of this chapter students will be able to Differentiate causative/risk/contributing factors of cardiovascular disorders Describe the clinical manifestations of patients with cardiovascular disorders Explain pathophysiologic process of cardiovascular disorders Discuss diagnostic procedures/evaluations used in the diagnosis of cardiovascular disorders Explain the medical and/ surgical managements of patients with cardiovascular disorders Apply nursing process in managing nursing care of patients with cardiovascular disorders.

4. Disorders of the Cardio-Vascular System The function of the cardiovascular system is to supply body cells and tissues with oxygen-rich blood and eliminate carbon dioxide (CO2) and cellular wastes. The cardiovascular system consists of the heart, the major blood vessels that empty into or exit directly from the heart, and a vast network of smaller peripheral blood vessels . The heart itself is about the size of a person’s fist. It lies below and slightly to the left of the midline of the sternum in the mediastinum, a portion of the thoracic cavity that also contains the trachea and major blood vessels. The upper portion of the heart is the base, and the tip is the apex

5. Disorders of the Cardio-Vascular System cont ’.. Heart Chambers The heart is a four-chambered muscular pump. The upper chambers, the right and left atria (singular, atrium), are receiving chambers for blood . The lower chambers, the right and left ventricles , are the heart’s major pumping chambers . A thick septum , or wall, separates the right side of the heart from the left side. The right atrium receives deoxygenated blood from the venous system , and the right ventricle pumps that blood to the lungs to be oxygenated. The left atrium receives oxygenated blood from the lungs , and the left ventricle pumps that blood to all the cells and tissues of the body . Therefore, the heart is a double pump —the right side facilitates pulmonary circulation , and the left side is responsible for systemic circulation .

6. Cardiac Tissue Layers Three distinct layers of tissue make up the heart wall. The outer layer is the epicardium , which is composed of fibrous and loose connective tissue . The middle layer , the myocardium , consists of muscle tissue and is the force behind the heart’s pumping action. The inner layer , the endocardium , is composed of a thin, smooth layer of endothelial cells . Folds of endocardium form the heart valves. The endocardium is in direct contact with the blood that passes through the heart. The pericardium is a saclike structure that surrounds and supports the heart.

7. Heart Valves The valves of the heart are membranous structures that ensure that blood passes through the heart in a one-way , forward direction . In a normal heart, the valves do not allow blood to backflow , or regurgitate , into the chamber from which it has come. The two atrioventricular (AV) valves separate the atria from the ventricles . They prevent blood from returning to the atria when the ventricles contract. These valves are cusped, or leaflike . The valve between the right atrium and right ventricle is the tricuspid valve . The word tricuspid signifies that the valve has three cusps. The valve between the left atrium and left ventricle is the bicuspid (two-cusped) valve, also known as the mitral valve

8. Heart Valves cont ’…. The other two valves, called the semilunar valves because they resemble portions of the moon , prevent blood from flowing back into the ventricles after the heart contracts. The valves are named for the blood vessel into which the blood is deposited. The valve between the right ventricle and pulmonary artery is the pulmonic (or pulmonary) valve . The valve between the left ventricle and aorta is the aortic valve . Contraction of the ventricles forces blood into the pulmonary artery and aorta. Relaxation follows, and the fall in pressure in the ventricles causes the pulmonic and aortic valves to close, preventing backflow into the ventricles.

9. Arteries and Veins Arteries carry oxygenated blood from the heart, and veins return deoxygenated blood to the heart. The smallest arteries are called arterioles , and the smallest veins are called venules . Arteries and arterioles are elastic and dilate or constrict to accommodate changes in blood flow. Veins have thinner walls than arteries because venous pressure is lower than arterial pressure. Arterioles branch into capillaries, which are microscopic vessels that form a connecting network between arterioles and venules . Capillaries are one cell layer thick and in direct contact with the cells of all tissues. This complex circulatory network delivers oxygen and metabolic substances to the cells.

10. Cont ’… Heart contraction moves blood from the heart into arteries and arterioles; skeletal muscle contraction compresses veins and propels blood back to the heart. Closure of successive sets of valves in veins keeps the blood from pooling under the influence of gravity Cardiopulmonary Circulation The largest veins , the inferior vena cava and superior vena cava , bring venous ( deoxygenated ) blood from all areas of the body into the right atrium . The right atrium fills with blood, and the tricuspid valve opens. Blood then travels into the right ventricle and is pumped into the pulmonary artery (the only artery in an adult that carries deoxygenated blood). The pulmonary artery branches to deliver venous blood to the right and left lungs. The lungs exchange the oxygen in inspired air for the CO2 in the venous blood.

11. Cont ’.. The CO2 is transferred into the alveoli and exhaled. The pulmonary veins then bring the oxygenated blood into the left atrium. The oxygenated blood flows out of the left atrium through the bicuspid, or mitral, valve and into the left ventricle. The left ventricle then pumps the blood through the aorta to all the body’s cells and tissues. Blood Supply to the Heart The left and right coronary arteries supply oxygenated blood to cardiac muscle.

12. Cardiac Cycle The term cardiac cycle refers to the contraction (systole) and relaxation (diastole) of both atria and both ventricles. The atria fill and then contract simultaneously; as they relax, the ventricles contract and relax.

13. Conduction System The conduction system sustains the electrical activity of the heart . It consists of the sinoatrial (SA) node, atrioventricular (AV) node, bundle of His, bundle branches, and Purkinje fibers . The SA node is an area of nerve tissue located in the posterior wall of the right atrium. The SA node is called the pacemaker of the heart because it initiates the electrical impulses that cause the atria and ventricles to contract . Normally , it produces between 60 and 100 impulses per minute; the average is approximately 72 impulses per minute.

14. Cardiac Output Cardiac output is the amount of blood pumped out of the left ventricle each minute. In a healthy adult, cardiac output ranges from 4 to 8 L/min (the average is approximately 5 L/min). Volume varies according to body size. Cardiac output can be increased in two ways: by increasing the heart rate and by increasing the stroke volume. Stroke volume is the amount of blood pumped per contraction of the heart. The stroke volume averages about 65 to 70 mL. The following formula is used to calculate cardiac output: Cardiac output = heart rate × stroke volume

15. Factors that alter heart rate Increase Heart Rate Exercise Fever Hyperthyroidism Hypoxia Dehydration Shock and hemorrhage Anxiety Caffeine Drugs: Central nervous system stimulants (cocaine, methamphetamine), adrenergic drugs (epinephrine, anticholinergic drugs (atropine) Alcohol withdrawal Decrease Heart Rate Rest Hypothermia Hypothyroidism Athletic conditioning Drugs: Cardiac glycosides (digoxin), central nervous system depressants (morphine), calcium channel blockers (verapamil, nifedipine ), beta adrenergic blockers (atenolol, metoprolol , propranolol)

16. Assessment o f The Cardiovascular System History The initial assessment includes the client’s (or family member’s) description of the symptoms the client experienced before and during admission. The history also includes the client’s past medical history and family medical history. The family medical history is important because many cardiac disorders have a familial or genetic predisposition

17. Physical Examination General Appearance An appraisal of the client’s general appearance may suggest problems that require further exploration. The client’s nonverbal behavior and body position may indicate that he or she is anxious, depressed, in pain, or uncomfortable. Pain Poor circulation, a common problem in clients with cardiovascular disorders, causes ischemia (reduced blood supply) to body organs. A classic sign of ischemia is pain, which results from a lack of oxygen in the tissue. Chest pain is a manifestation of ischemia to the heart muscle. Leg pain, especially with activity, can indicate inadequate oxygenation to leg muscles.

18. Physical ex.. Vital Signs Temperature Fever is characteristic in some types of heart disease. It can accompany the inflammatory response when myocardial cells are damaged after an acute myocardial infarction (MI; heart attack) or infections such as rheumatic fever and bacterial endocarditis. Pulse When taking a client’s pulse, the nurse notes its rate, rhythm, and quality . Pulse rhythm is the pattern of the pulsations and the pauses between them. A normal pulse is felt regularly with a similar length of pause. The pulse quality refers to its palpated volume. Pulse volume is described as feeling full, weak, or thready , meaning barely palpable.

19. cont.’… Respiratory Rate The nurse counts the respiratory rate for 60 seconds. He or she observes the character of the respirations, noting whether the client’s breathing is effortless or labored ( dyspneic ), deep or shallow, noisy or quiet. Blood Pressure Cardiac disorders often are associated with changes in BP. If the client is not acutely ill, the nurse takes the BP with the client in the lying, sitting, and standing positions (orthostatic vital signs )

20. Heart Sounds Normal Heart Sounds Auscultation of the heart requires familiarization with normal and abnormal heart sounds. The first heart sound (‘‘ lub ’’), referred to as S1 , is the closing of the mitral and tricuspid valves . S1 is heard loudest over the apex of the heart and occurs nearly simultaneously with the palpated pulse. The second heart sound (‘‘dub’’), referred to as S2 , is the closing of the aortic and pulmonic valves . S2 is heard loudest with the stethoscope in the aortic area , which is at the second intercostal space to the right of the sternum

21. Abnormal Heart Sounds All other heart sounds are abnormal and take considerable practice to recognize. A sound that follows S1 and S2 is called an S3 heart sound or a ventricular gallop. When the three sounds are heard together, some say the cadence sounds like ‘‘ lub -dub- dee .’’ An S3, although normal in children, often is an indication of heart failure in an adult. An extra sound just before S1 is an S4 heart sound , or atrial gallop . Some say this sound resembles the word ‘‘ lub - lub -dub.’’ An S4 sound often is associated with hypertensive heart disease .

22. Cont ’…. Peripheral Pulses The nurse palpates the radial arteries and the major arteries of the leg bilaterally during the physical assessment. He or she records the presence or absence of these pulses and their strength . Skin Many clients with cardiac disorders exhibit changes in skin color (e.g., cyanosis, pallor). A good light is necessary when assessing skin color . Cyanosis can be detected by carefully noting color changes in the oral mucous membranes as well as on the lips, earlobes, skin, and nail beds.

23. Cont ’… Peripheral Edema Edema occurs when blood is not pumped efficiently or plasma protein levels are inadequate to maintain osmotic pressure. When blood has nowhere else to go, the extra fluid enters the tissues. Particular areas for examination are the dependent parts of the body, such as the feet and ankles. Other areas prone to edema are the fingers, hands, and over the sacrum . To assess for edema , the examiner gently presses his or her fingers into the skin and then quickly releases. If the marks of the fingers remain, the effect is termed pitting edema . Edema is evaluated on a scale of + 1 to +4 , depending on the depth of the pit and the amount of time it takes the pit to disappear. The higher the number, the more pronounced is the edema .

24. Cont ’… Weight Weight gain can indicate edema . A rapid gain in weight often means that edema is increasing. Weight loss often reflects the loss of excess fluid from the tissues and is used to evaluate the effectiveness of drug therapy, especially diuretics. Jugular Veins If the right side of the heart fails to pump efficiently, blood becomes congested in the neck veins. With the client sitting at a 45° angle, the client turns his or her head to the left or right so the nurse can inspect the external jugular vein. Distention of this vein usually indicates increased fluid volume and pressure in the right side of the heart.

25. Cont ’… Lung Sounds If the left side of the heart fails to pump efficiently, blood backs up into the pulmonary veins and lung tissue. The nurse auscultates the lungs for abnormal and normal breath sounds. With left-sided congestive heart failure, auscultation reveals a crackling sound and possibly wheezes and gurgles . Wet lung sounds are accompanied by dyspnea and an effort to sit up to breathe. If uncorrected, left-sided heart failure is followed by right-sided heart failure because the circulatory system is a continuous loop.

26. Cont … Sputum Clients with cardiac disease may have a productive or nonproductive cough. The nurse notes the type and frequency of the cough and the amount and appearance of the sputum. These findings can be important in diagnosing heart failure or other pulmonary complications . Mental Status Some clients with cardiac disorders may be alert and oriented ; others may be confused and disoriented. Confusion or disorientation can result from a decrease in the oxygen supply to the brain (cerebral ischemia) as a result of poor circulation. Chest pain and impaired breathing can create anxiety.

27. Diagnostic Tests Laboratory Tests Various general laboratory tests are used in the diagnosis of heart disease and in monitoring the client’s progress. Blood chemistries , such as fasting blood glucose and serum electrolyte, cholesterol, and triglyceride levels, may be used as parts of the diagnostic process. Analysis of serum enzymes and isoenzymes may also be used. Radiography and Radionuclide Studies Chest radiography and fluoroscopy determine the size and position of the heart and condition of the lungs. These studies also are used to guide the insertion and confirm the placement of cardiac catheters and pacemaker wires. CT scanning and magnetic resonance imaging are used to determine heart size and detect lung involvement.

28. Cont … Magnetic Resonance Imaging (MRI) Magnetic resonance imaging (MRI) is a diagnostic tool used to identify disorders that affect many different structures in the body without performing surgery Cardiovascular MRI scanning can provide data about cardiac anatomy, function, blood flow, metabolism, and circulatory perfusion with a single examination. The image of blood within the heart appears white; dense tissues such as cardiac muscle and the valves are dark gray .

29. Cont …. Echocardiography Echocardiography uses ultrasound waves to determine the functioning of the left ventricle and to detect cardiac tumors , congenital defects, and changes in the tissue layers of the heart. Electrocardiography Electrocardiography (ECG) is the graphic recording of the electrical currents generated by the heart muscle. During electrocardiography, color-coded electrodes matched to corresponding lead wires connect the client to the recording machine. The electrodes are coated with conductive gel and applied to the skin surface of the wrists, ankles, and chest.

30. Cont … Ambulatory Electrocardiography Ambulatory ECG, or Holter monitoring, is the recording of an ambulatory client’s cardiac rate and rhythm over 24 to 48 hours as the client performs daily activities .

31. Infectious And Inflammatory Disorders of The Heart Rheumatic Fever And Rheumatic Carditis Rheumatic fever is a systemic inflammatory disease that sometimes follows a group A streptococcal infection of the throat . Rheumatic carditis refers to the inflammatory cardiac manifestations of rheumatic fever in either the acute or later stage. Cardiac structures that usually are affected include the heart valves (particularly the mitral valve), endocardium , myocardium, and pericardium.

32. Pathophysiology and Etiology The inflammatory symptoms of rheumatic carditis are believed to be induced by antibodies originally formed to destroy the group A beta- hemolytic streptococcal microorganisms . The antibodies, however, ‘‘mistakenly’’ cross-react against the proteins in the connective tissue of the heart, joints, skin, and nervous system. This cross-reaction causes valvular damage and pancarditis , inflammation of all layers of the heart (endocardium, myocardium, and pericardium). As the antibody response ensues, white blood cells (WBCs) migrate to the endocardium, causing inflammatory debris to accumulate as vegetations around the valve leaflets. When the inflammatory process is relieved, fibrinous tissue replaces the damaged areas. This fibrinous tissue fuses or thickens valve leaflets and shortens the chordae tendineae ; thus, the valves may lose their ability to open fully or close tightly.

33. Patho ….. The fibrinous replacements also cause surface irregularities around the valves, making them prone to future colonization by blood-borne bacteria . The antibodies also attack cardiac myosin, the muscle protein in myocardial tissue. Because myosin is instrumental in cardiac muscle contraction, rheumatic carditis may cause weakened heart contractions and heart failure. If the pericardium is involved, it becomes tough and leathery from accumulated fibrinous fluid that interferes with the heart’s ability to stretch and fill with blood. Tachydysrhythmias , fast abnormal heart rhythms, develop to compensate for the decreased cardiac output (the volume of blood ejected from the left ventricle per minute). After the acute episode, most clients recover, but valvular changes remain.

34. Assessment Findings Signs and Symptoms Acute rheumatic fever is most common in children 2 to 3 weeks after a streptococcal infection. The sequelae , abnormal conditions that follow a disease, include carditis ( inflammation of the layers of the heart), polyarthritis ( inflammation of more than one joint), rash, subcutaneous nodules, and chorea characterized by involuntary grimacing and an inability to use skeletal muscles in a coordinated manner. Adults do not exhibit the same degree and range of symptoms as young children. A mild fever, if untreated, continues for several weeks. The heart rate is rapid and the rhythm may be abnormal.

35. Cont …. A red, spotty rash referred to as erythema marginatum appears on the trunk but disappears rapidly, leaving irregular circles on the skin. Several joints, most commonly the knees, ankles, hips, and shoulders, become swollen, warm, red, and painful. The involvement migrates across joints. Sometimes marble-sized nodules appear around the joints. Central nervous system manifestations result in chorea. Cardiac complications may develop: A heart murmur suggests valve damage; A pericardial friction rub indicates pericarditis; and Congestive heart failure (CHF) develops if the myocardium fails to compensate for functional demands.

36. Diagnostic Findings No laboratory test is specific for the diagnosis of rheumatic fever. The results of laboratory tests such as an Antistreptolysin O titer , Erythrocyte sedimentation rate (ESR), and C-reactive protein are elevated, indicating an inflammatory process involving the streptococcal organism. Specific cardiac tests, such as electrocardiography (ECG) and echocardiography , may show structural changes in the valves, size of the heart, and the heart’s ability to contract.

37. Medical and Surgical Management Intravenous (IV) antibiotics are given. Penicillin is the drug of choice for group A streptococci, unless contraindicated because of an allergy. For clients who are allergic to the penicillin family of antibiotics, another antibiotic such as azithromycin, clindamycin, or vancomycin may be prescribed. Cephalosporins such as cephalexin or cefadroxil may be prescribed if the client has not had a previous severe allergic reaction to penicillin. Bed rest may be indicated, depending on the client’s condition. Aspirin is used to control the formation of blood clots around heart valves. Steroids are used to suppress the inflammatory response.

38. Nursing Management The nurse administers prescribed drug therapy and monitors for therapeutic and adverse effects. He or she plans diversional activities that require minimal activity, such as reading and putting puzzles together, to reduce the work of the myocardium and counteract the boredom of bed rest. Focused cardiac assessments help to track the progression or improvement of heart involvement.

39. Nutrition for The Client with Rheumatic Carditis A full liquid diet is used in the initial treatment of rheumatic heart disease and is progressed as tolerated. Sodium is restricted if the client has edema or is treated with steroids. Anorexia and weight loss are common side effects of infections ; calories and protein should be increased as needed to replenish losses. Fever increases fluid requirements. Encourage small, frequent feedings to maximize intake.

40. Infective Endocarditis Infective endocarditis (formerly called bacterial endocarditis ) is inflammation of the inner layer of heart tissue as a result of an infectious microorganism. Although clients with rheumatic carditis do develop endocarditis, it is initially considered an autoimmune response—not an infection—because no microorganism can be isolated from blood or other cultured specimens. Subsequent to the initial rheumatic carditis , however, the valvular changes increase the client’s susceptibility to endocardial colonization by pathogens Pathophysiology and Etiology The microorganisms that cause infective endocarditis include bacteria and fungi. Streptococcus viridans and Staphylococcus aureus are the bacteria most frequently responsible for this disorder. They are found abundantly on the skin and mucous membranes of the mouth, nose, throat, and other cavities.

41. Pathophysiology and Etiology Streptococci Account for 55% of cases of endocarditis Group A beta-haemolytic Attack normal or damaged heart valves and may cause rapid destruction S . bovis Related to GI malignancy S . viridans Tend to affect previously damaged heart valves Staphylococci Cause 30% of cases of endocarditis S . aureus Virulent strain with high mortality rate S. epidermidis Associated with dental procedures and valve replacements S . faecalis Fungi Candida Increased incidence in IV drug users

42. Diagnostic Findings Anemia and slight leukocytosis are common findings. A series of three blood cultures collected over 1 to 24 hours usually identifies the microorganism circulating in the blood. Some cultured specimens require incubation for 3 weeks or more to identify accurately the infecting species . Transesophageal echocardiography is more likely than transthoracic echocardiography to reveal the vegetations , altered valvular function , and impaired pumping quality of the ventricles . ECG may reveal abnormalities in heart rhythm if the vegetations involve a valve close to conduction tissue.

43. Medical and Surgical Management High doses of an IV antibiotic to which the organism is susceptible are prescribed initially. Antibiotic therapy extends at least 2 to 6 weeks. It is resumed if the infection recurs after discontinuation of the drug. Bed rest is ordered initially . If a heart valve has been severely damaged and drug therapy does not adequately support the heart in failure, valve replacement may be necessary

44. Nursing Management Many clients cannot appreciate the danger of the disease without seeing external signs of the damage. The nurse gently but firmly reminds the client to limit activity. He or she continually assesses for changes in weight and pulse rate and rhythm and notes and reports new symptoms. The nurse administers prescribed antibiotics provides appropriate health information for clients

45. Inflammatory Disorders of The Peripheral Blood Vessels Thrombophlebitis Thrombophlebitis is an inflammation of a vein accompanied by clot or thrombus formation . Although clots can form in any blood vessel, the veins deep in the lower extremities are most commonly affected. In such cases, the condition is referred to as deep vein thrombosis (DVT). Thrombi that form in or above the popliteal vein of the leg are at high risk for migration toward the pulmonary circulation; these cases are referred to as a pulmonary embolus (PE).

46. Pathophysiology and Etiology When the inner lining of a vein is irritated or injured , platelets clump together , forming a clot . The clot interferes with blood flow, causing congestion of venous blood distal to the blood clot. Sometimes collateral vessels recirculate the blood blocked by the clot. Accumulated waste products in the blocked vessel irritate the vein wall, initiating an inflammatory response. The increased permeability of cells and the convergence of leukocytes and lymphocytes cause the area to swell, redden, and feel warm and tender . The development of a PE may complicate thrombophlebitis if the clot in the extremity becomes mobile and moves in the venous circulation to the lungs

47. Assessment Findings Signs and Symptoms Clients with thrombophlebitis often complain of discomfort in the affected extremity. Calf pain that increases on dorsiflexion of the foot is referred to as a positive Homans ’ sign . Heat, redness, and swelling develop along the length of the affected vein. Capillary refill takes less than 2 seconds because of venous congestion. The client often has a fever, malaise , fatigue, and anorexia.

48. Diagnostic Tests Most cases of thrombophlebitis are diagnosed according to clinical findings alone. Doppler ultrasound is a noninvasive diagnostic technique for imaging blood flow through cardiovascular structures that may detect an area of venous obstruction.

49. Medical and Surgical Management Complete rest of the arm or leg is essential to prevent the thrombus from breaking free and floating in the circulation (embolus ). Anticoagulant therapy with heparin , are prescribed to decrease the incidence of future clot formation. With the advent of low-molecular-weight heparins such as enoxaparin ( Lovenox ), some clients with thrombophlebitis in which the thrombi are small are not hospitalized but treated at home. People with repeated episodes may be placed on oral anticoagulant therapy for 3 to 6 months . Continuous warm, wet packs are ordered to improve circulation, ease pain, and decrease inflammation. Surgical intervention may be necessary when a clot occludes a large vein or the danger of a PE arises. Thrombectomy , the surgical removal of a clot, is performed if the clot interferes with venous drainage from a large vein such as the femoral vein.

50. Occlusive disorders of peripheral blood vessels Occlusive disorders of peripheral blood vessels also contribute to morbidity and mortality. The most common causes of occlusive vascular diseases are arteriosclerosis, atherosclerosis , clot formation, and vascular spasm. Venous insufficiency and valvular incompetence also foster peripheral vascular disorders.

51. Arteriosclerosis Arteriosclerosis refers to the loss of elasticity or hardening of the arteries that accompanies the aging process. As cells in arterial tissue layers degenerate with age, calcium is deposited in the cytoplasm. The calcium causes the arteries to lose elasticity . As the left ventricle contracts, sending oxygenated blood from the heart , the rigid arterial vessels fail to stretch. The potential result is a reduced volume of oxygenated blood delivered to organs such as the myocardium , brain, kidneys, and extremities.

52. Atherosclerosis Atherosclerosis is a condition in which the lumen of arteries fill with fatty deposits called plaque . The plaque is chiefly composed of cholesterol, a fatty (lipid) substance . Atherosclerosis is a more modifiable contributor than arteriosclerosis to vascular disease. Therefore , it is the focus of attention and research into the mechanisms that contribute to plaque formation and its reduction to decrease vascular disease .

53. Pathophysiology and Etiology Areas of atherosclerotic research include determining the mechanisms by which lipids are formed and metabolized, and the roles that body fat, obesity, infectious and inflammatory processes may play in contributing to higher risk factors for vascular diseases . Hyperlipidemia , or high levels of blood fat, triggers atherosclerotic changes. Factors such as gender, heredity, diet, diseases such as metabolic syndrome, and inactivity individually or collectively contribute to hyperlipidemia Infection; a current hypothesis is that atherosclerosis is linked to prior infections with Chlamydia pneumoniae , a bacterium that commonly causes respiratory infections Inflammation; indicates a relationship between body fat and the production of inflammatory and thrombotic (clot-facilitating) proteins.

54. Cont ’… A client with elevated lipid levels who also has other risk factors (cigarette smoking, stressful lifestyle , obesity, diabetes mellitus, hypertension, or a previous infection with C. pneumoniae or other microorganisms) is predisposed to the accelerated accumulation of fatty plaque beneath the intimal layer of the arteries .

55. Dysrhythmias Dysrhythmias are disorders of the formation or conduction (or both) of the electrical impulse within the heart. These disorders can cause disturbances of the heart rate, the heart rhythm , or both. Dysrhythmias may initially be evidenced by the hemodynamic effect they cause ( eg , a change in conduction may change the pumping action of the heart and cause decreased blood pressure). Dysrhythmias are diagnosed by analyzing the electrocardiographic (ECG) wave form . Their treatment is based on frequency and severity of symptoms produced. Dysrhythmias are named according to the site of origin of the impulse and the mechanism of formation or conduction involved. For example, an impulse that originates in the sinoatrial (SA) node and at a slow rate is called sinus bradycardia .

56. Normal Sinus Rhythm Normal sinus rhythm occurs when the electrical impulse starts at a regular rate and rhythm in the sinus node and travels through the normal conduction pathway. Normal sinus rhythm has the following characteristics. Ventricular and atrial rate: 60 to 100 in the adult Ventricular and atrial rhythm: Regular QRS shape and duration: Usually normal, but may be regularly abnormal P wave: Normal and consistent shape; always in front of the QRS PR interval: Consistent interval between 0.12 and 0.20 seconds P:QRS ratio: 1:1

57. Normal Sinus Rhythm

58. Types of Dysrhythmias Dysrhythmias include sinus, atrial, junctional , and ventricular dysrhythmias and their various subcategories Sinus Node Dysrhythmias Sinus Bradycardia. Sinus bradycardia occurs when the sinus node creates an impulse at a slower-than-normal rate . Causes include lower metabolic needs ( eg , sleep, athletic training , hypothyroidism), vagal stimulation ( eg , from vomiting , suctioning, severe pain, extreme emotions ), medications ( eg , calcium channel blockers, amiodarone , beta-blockers ), idiopathic sinus node dysfunction, increased intracranial pressure (ICP), and myocardial infarction (MI), especially of the inferior wall.

59. Sinus bradycardia Sinus bradycardia has the following characteristics: Ventricular and atrial rate: Less than 60 in the adult Ventricular and atrial rhythm: Regular QRS shape and duration: Usually normal, but may be regularly abnormal P wave: Normal and consistent shape; always in front of the QRS PR interval: Consistent interval between 0.12 and 0.20 seconds P:QRS ratio: 1:1 Medical management Atropine, 0.5 mg given rapidly as an intravenous (IV) bolus every 3 to 5 minutes to a maximum total dose of 3 mg, is the medication of choice in treating symptomatic sinus bradycardia.

60. Sinus Tachycardia. Sinus tachycardia occurs when the sinus node creates an impulse at a faster-than-normal rate . Causes may include the following: Physiologic or psychological stress ( eg , acute blood loss , anemia , shock, hypervolemia, hypovolemia, heart failure, pain, hypermetabolic states, fever, exercise , anxiety) Medications that stimulate the sympathetic response ( eg , catecholamines , aminophylline, atropine), stimulants ( eg , caffeine, alcohol, nicotine), and illicit drugs ( eg , amphetamines, cocaine, Ecstasy) Enhanced automaticity of the SA node and/or excessive sympathetic tone with reduced parasympathetic tone , a condition called inappropriate sinus tachycardia

61. Sinus tachycardia Sinus tachycardia has the following characteristics: Ventricular and atrial rate: Greater than 100 in the adult, but usually less than 120 Ventricular and atrial rhythm: Regular QRS shape and duration: Usually normal, but may be regularly abnormal P wave: Normal and consistent shape; always in front of the QRS, but may be buried in the preceding T wave PR interval: Consistent interval between 0.12 and 0.20seconds P:QRS ratio: 1:1

62. Cardiac arrest Cardiac arrest occurs when the heart ceases to produce an effective pulse and circulate blood. It may be caused by a cardiac electrical event ( ie , dysrhythmia) such as ventricular fibrillation , progressive profound bradycardia, or when there is no heart rhythm at all ( asystole ). Cardiac arrest may follow respiratory arrest; it may also occur when electrical activity is but there is ineffective cardiac contraction or circulating volume, which is called pulseless electrical activity (PEA). PEA can be caused by hypovolemia ( eg , with excessive bleeding), hypoxia, hypothermia, hyperkalemia , massive pulmonary embolism, myocardial infarction, and medication overdose ( eg , beta-blockers, calcium channel blockers).

63. Clinical Manifestations In cardiac arrest, consciousness, pulse, and blood pressure are lost immediately. Ineffective respiratory gasping may occur . The pupils of the eyes begin dilating within 45 seconds. Seizures may or may not occur. The risk of irreversible brain damage and death increases with every minute from the time that circulation ceases. The interval varies with the age and underlying condition of the patient. During this period, the diagnosis of cardiac arrest must be made and measures must be taken immediately to restore circulation.

64. Emergency Management: Cardiopulmonary Resuscitation Cardiopulmonary resuscitation (CPR) provides blood flow to vital organs until effective circulation can be reestablished . Following recognition of unresponsiveness, lack of pulse and respiration, the protocol for basic life support is initiated . Assessment and intervention for the patient with cardiac arrest includes utilization of the ABCD protocol. The ABCDs of basic CPR include airway, breathing, circulation, and defibrillation