Inflammatory & Structural Heart Disorders: IE and CMP Study Notes

Infective Endocarditis (IE): Overview

  • Inflammatory and infectious involvement of the endocardium and heart valves leading to impaired cardiac output (CO) and decreased tissue perfusion. Patients may experience pain, hyperthermia, and reduced functional/cognitive abilities. Education is key for management and prevention.

IE: Epidemiology, Etiology, and Classification

  • IE is a disease of the endocardium and valves with poor prognosis and decreasing life expectancy; incidence has risen, largely due to increased IV drug use (IVDA).
  • Classification by cause or site: e.g., IVDA IE, fungal IE, prosthetic valve endocarditis (PVE).
  • Temporal forms: subacute vs acute
    • Subacute: affects those with preexisting valve disease over months
    • Acute: affects those with healthy valves, rapidly progressive

Etiology and Pathophysiology

  • IE occurs when blood flow brings organisms to contact and infect previously damaged valves or endothelial surfaces.
  • Common organisms:
    • Staphylococcus aureus (≈ 50% of cases)
    • Streptococcus viridans
    • Coagulase-negative staphylococci
    • HACEK group (Haemophilus, Actinobacillus, Cardiobacterium, Eikenella, Kingella)
  • Organisms form biofilms, protecting them from immune defenses and reducing antimicrobial efficacy.
  • At-risk populations include those with various cardiac and noncardiac conditions (Table 40.1).
  • Key risk factors (main):
    • History of IE
    • IV drug use
    • Prosthetic valve
    • Healthcare-associated infection from intravascular devices (e.g., MRSA)
    • Renal dialysis

IE Stages and Pathology

  • Typical development in 3 stages:
    1) Bacteremia
    2) Adhesion
    3) Vegetation formation on valve surface or endocardium
  • Vegetations: fibrin, leukocytes, platelets, microbes
  • Embolization: up to 10.5\% of IE cases develop emboli
    • Left-sided vegetations → brain, kidneys, spleen, limbs (arterial emboli)
    • Right-sided vegetations → lungs (pulmonary emboli)
  • Infection may spread locally causing valve dysfunction, dysrhythmias, and heart failure (HF); invasion of myocardium can cause HF, sepsis, heart block.

Clinical Manifestations of IE

  • Most common sign: fever (can be absent in older adults or immunocompromised)
  • Other systemic symptoms: chills, weakness, malaise, fatigue, anorexia
  • Vascular phenomena:
    • Splinter hemorrhages in nail beds
    • Petechiae on conjunctivae, lips, buccal mucosa, palate, ankles, feet, antecubital and popliteal areas
  • Other classic findings:
    • Osler’s nodes: painful, tender, red/purple pea-sized lesions on fingertips/toes
    • Janeway lesions: flat, painless red spots on fingertips, palms, soles
    • Roth’s spots: hemorrhagic retinal lesions on eye exam
  • Cardiac findings: new or worsening systolic murmur (murmurs often present; murmur may be absent with tricuspid IE due to audible limitations)
  • HF is common: occurs in up to 80\% with aortic valve IE and 50\% with mitral valve IE

Diagnostic Studies and Duke Criteria

  • Thorough health history: recent dental/urologic/surgical/gynecologic procedures (past 3–6 months); IVDA history; prior heart disease or infections; prior catheterizations, intravascular device placements, or dialysis.
  • Blood cultures: typically 3 cultures drawn over 1 hour from 3 different venipuncture sites; positive in most IE cases
    • Culture-negative IE can occur with recent antibiotic use (≤ 2 weeks) or fastidious/undetected pathogens
  • Laboratory findings: mild leukocytosis (acute IE); elevated ESR and CRP
  • Imaging: echocardiography detects vegetations
  • Duke Criteria for IE diagnosis:
    • Major criteria: positive blood cultures for IE-associated organisms; evidence of endocardial involvement; new valvular vegetation
    • Minor criteria: predisposition (heart condition/IVDA), vascular phenomena, immunologic phenomena, microbiologic evidence not meeting major criteria, or echocardiographic findings consistent with IE but not meeting major criteria
    • Diagnostic thresholds: 2 major criteria and 1 minor, or 1 major and 3 minor, or 5 minor criteria
  • Additional notes: Guidelines for diagnosis rely on the Duke Criteria

Interprofessional Care: Prophylaxis and Therapy

  • Prophylaxis: Certain situations require antibiotic prophylaxis (Table 40.2) to prevent IE
  • Antibiotic therapy:
    • Tailored to causative organism from blood cultures
    • Long-term therapy needed to eradicate dormant bacteria within valvular vegetations; complete clearance often takes weeks; relapses are common
    • Monitor effectiveness with follow-up blood cultures; if cultures remain positive, reassess for inappropriate antibiotics, abscess, or alternative diagnosis
    • Practical approach: obtain 2 blood culture sets every 24–48 hours until infection cleared
  • Follow-up after antibiotics: echocardiography and inflammatory markers at 1, 3, 6, and 12 months
  • Fungal IE and PVE: poor response to antibiotics alone; require early valve replacement followed by prolonged antibiotics (≥ 6 weeks)
  • Valve replacement surgery: performed in 50\%$-$60\% of IE cases; indications include valve dysfunction causing HF, prevention of embolization, or uncontrolled infection
  • Fever management post-treatment: aspirin, acetaminophen, fluids, and rest; complete bed rest not usually needed unless fever persists or HF signs
  • IE with HF: poor drug response; can be life-threatening

Nursing Management: Assessment and Planning

  • Assessment focuses on IE-specific signs and potential complications (Table 40.3): vital signs, heart sounds for new or changed murmurs, extra sounds (e.g., S3); assess arthralgia/myalgias and ROM; inspect for petechiae, splinter hemorrhages, Osler’s nodes; assess for hemodynamic or embolic complications
  • Clinical problems: impaired cardiac output, infection, fatigue, substance use
  • Goals: normal or baseline cardiac function, ADLs without fatigue, understanding/t adherence to treatment plan to prevent recurrence

Nursing Interventions and Health Promotion

  • Health promotion for high-risk patients (Table 40.1, 40.2): avoid people with infections, report cold/flu symptoms promptly, rest adequately, maintain good oral hygiene, regular dental visits, inform healthcare providers before invasive procedures, potential antibiotic prophylaxis
  • Address IVDA: refer for drug rehabilitation

Ambulatory Care and Home Management

  • IE typically requires 4–6 weeks of antibiotics; home IV antibiotics may be feasible if hemodynamically stable and adherent
  • Home assessment: ensure adequate support; plan for vigilant monitoring
  • Patient/caregiver education:
    • Monitor body temperature; persistent fever may indicate ineffective antibiotics
    • Recognize complications: stroke, pulmonary edema, HF (e.g., changes in mental status, dyspnea, chest pain, unexplained weight gain)
    • Ensure rest and gradual activity; avoid bed rest unless fever or HF signs persist
    • Mobility precautions: elastic stockings, ROM exercises, deep breathing, coughing every 2 hours
    • Manage anxiety and fear; coping strategies
    • Monitor labs (including blood cultures) to gauge antibiotic effectiveness; IV lines patency and complications (phlebitis)
    • Adherence to prescribed antibiotics; reinfection prevention through nutrition, dental care, prompt treatment of infections
    • Prophylactic antibiotics before certain invasive procedures (Table 40.2)
  • Evaluation: outcomes include maintained tissue/organ perfusion, normal body temperature, improved physical and emotional comfort

Cardiomyopathy (CMP): Overview and Classification

  • CMP is a group of diseases that directly affect myocardial structure or function; classified as primary (idiopathic heart-muscle disease) or secondary (another disease process causes myocardial disease).
  • Three major CMP types: dilated, hypertrophic, restrictive
  • Takotsubo cardiomyopathy: transient syndrome with apical akinesis mimicking acute coronary syndrome; chest pain, ST elevation, elevated cardiac biomarkers, but no significant CAD on angiography; often stress-related and more common in postmenopausal women; management largely supportive; ~5% require anticoagulation
  • CMP leading to cardiomegaly and HF is a primary reason for heart transplantation
  • Treatments may include LVAD as a bridge to recovery or transplant, as well as device therapies (cardiac resynchronization therapy, ICD)
  • About 50% of heart transplants are performed for CMP; donor hearts are scarce; CMP patients are severely ill with poor prognosis without advanced therapy

Dilated Cardiomyopathy (DCM)

  • Etiology and epidemiology:
    • Most common CMP type; ~5–8 per 100,000 people; HF in 20\%–45\% of cases
    • Primary myocardial disorder with genetic or acquired origins; alcohol-related DCM is a distinct subset
    • Diffuse inflammation with rapid degeneration leads to ventricular dilation, impaired systolic function, atrial enlargement, and left-ventricular blood stasis
    • SCD due to dysrhythmias is a leading cause of death in idiopathic DCM
  • Pathophysiology: ventricular dilation causes cardiomegaly and contractile dysfunction; walls do not hypertrophy
  • Clinical manifestations: may be acute post-infection or insidious; fatigue, dyspnea on exertion, orthopnea, paroxysmal nocturnal dyspnea, dry cough, palpitations; abdominal bloating, nausea, anorexia; signs include S3/S4, dysrhythmias, murmurs, crackles, edema, weak pulses, pallor, hepatomegaly, JVD; risk of thrombus formation and systemic embolization due to stasis
  • Diagnostic Studies:
    • History and exclusion of other HF causes; echocardiography is cornerstone
    • EF < 0.20 (20%) has a 50\% mortality at 1 year
    • Chest X-ray: cardiomegaly with pulmonary venous hypertension and possible pleural effusions
    • ECG: tachycardia, bradycardia, dysrhythmias
    • Lab: elevated BNP when HF is present
    • Coronary angiography to evaluate CAD; endomyocardial biopsy during right heart cath to identify infectious or other etiologies
  • Interprofessional and Nursing Care:
    • Focus on HF management: improve contractility, reduce preload and afterload
    • Therapy guided by disease stage (Table 38.3); Class IV (stage D) HF is more palliative
    • Pharmacologic options:
    • Nitrates (e.g., nitroglycerin) and diuretics reduce preload
    • ACE inhibitors reduce afterload
    • β-blockers (e.g., metoprolol) and aldosterone antagonists (e.g., spironolactone) mitigate neurohormonal activation
    • Antidysrhythmic drugs as needed; anticoagulation to reduce embolic risk
    • Non-pharmacologic and device therapies:
    • Cardiac rehabilitation; CRT; ICDs
    • VAD support for severe HF or bridging to transplant
    • Statins may be beneficial in some cases
    • Secondary DCM (e.g., alcohol-related): address underlying cause (e.g., abstinence from alcohol)
    • Hospitalization for inotropes (e.g., dobutamine, milrinone) with diuresis as needed; some care may occur in outpatient or home under supervision
    • Prognosis: often poor; management focuses on maximizing function and quality of life

Hypertrophic Cardiomyopathy (HCM) and Obstructive Forms

  • Etiology and pathophysiology: genetic disorder with asymmetric LV hypertrophy without dilation; can include hypertrophic obstructive cardiomyopathy (HOCMP/ASH) where the septum encroaches on outflow tract
  • Epidemiology: less common than DCM; more common in men; often diagnosed in young, active individuals; major cause of sudden cardiac death (SCD) in otherwise healthy young people; 1st-degree relatives should be screened
  • Key features (the four main characteristics):
    1) Massive ventricular hypertrophy
    2) Rapid, forceful LV contraction
    3) Impaired relaxation (diastole)
    4) Outflow obstruction (not present in all patients)
  • Cardiovascular impact: thickened septum and wall restrict filling, leading to reduced CO especially with exertion
  • Clinical manifestations: may be asymptomatic or present with exertional dyspnea, fatigue, angina, syncope (especially with activity due to outflow obstruction); palpitations
  • Diagnostic Studies:
    • Exam: enlarged/apical impulse, S4, systolic murmur between apex and left sternal border (4th intercostal space)
    • ECG: LV hypertrophy, ST-T changes, pathological Q waves; dysrhythmias
    • Echocardiography: main diagnostic tool; shows wall thickness and diastolic dysfunction
    • Additional: heart catheterization and nuclear stress testing may aid in diagnosis and management
  • Interprofessional and Nursing Care:
    • Goals: improve ventricular filling and reduce LV outflow obstruction
    • Pharmacologic management: β-blockers (e.g., metoprolol) or non-dihydropyridine calcium channel blockers (e.g., verapamil) to reduce outflow obstruction and decrease contractility
    • Antiarrhythmics: amiodarone or sotalol; not all prevent SCD
    • ICD for SCD risk; AV pacing can reduce obstruction by altering depolarization
    • Surgical options: ventriculomyotomy and myectomy to remove obstructing septal muscle; improves symptoms and exercise tolerance
    • Nonsurgical alternative: percutaneous transluminal septal myocardial ablation (PTSMA) via septal artery alcohol injection to create septal infarction and reduce obstruction; potential complications include conduction blocks and MI
    • Patient education: avoid strenuous activity and dehydration (which can worsen obstruction); rest and leg elevation recommended to improve venous return; nitrates may worsen symptoms by decreasing venous return and increasing obstruction

Restrictive Cardiomyopathy (RCM)

  • Etiology and pathophysiology: least common CMP; impaired diastolic filling with preserved systolic function; stiff ventricles reduce filling; primary disease with secondary causes including amyloidosis, endocardial fibrosis, sarcoidosis, thoracic radiation
  • Hemodynamics: high diastolic filling pressures needed to maintain CO
  • Clinical manifestations: fatigue, exercise intolerance, dyspnea; possible angina, orthopnea, syncope, palpitations; signs of HF with dyspnea, edema, weight gain, ascites, hepatomegaly, JVD
  • Diagnostic Studies: chest X-ray may be normal or show cardiomegaly with atrial enlargement; echocardiography shows normal LV size with thickened wall, mildly dilated right ventricle, dilated atria; endomyocardial biopsy, CT, nuclear imaging can aid diagnosis
  • Interprofessional and Nursing Care:
    • No specific cure; management focuses on HF relief and treating underlying disease
    • HF therapies and dysrhythmia management as per standard HF guidelines
    • Consider heart transplantation in selected cases
    • Similar nursing care to HF: monitor filling pressures and rhythm; educate on activity limits and IE prophylaxis before invasive procedures

Takotsubo Cardiomyopathy (Stress-Induced) and Related Concepts

  • Takotsubo cardiomyopathy: transient LV dysfunction with apical akinesis mimicking ACS; ST elevation and elevated cardiac markers but no culprit CAD on angiography
  • More common in postmenopausal women; acute, stress-related etiology; treatment is supportive; most patients recover
  • In CMP context, consider VAD or transplant for end-stage CMP and palliative/transitional approaches as indicated

General Interventions and Nursing Considerations Across CMP

  • HF management is central: improve CO, reduce preload/afterload, and manage dysrhythmias
  • Pharmacologic strategies commonly include:
    • Nitrates and diuretics for preload reduction
    • ACE inhibitors for afterload reduction
    • β-Blockers and aldosterone antagonists for neurohormonal modulation
    • Antiarrhythmics as needed; anticoagulation to prevent emboli in certain contexts
  • Device therapies: ICDs, CRT, VADs as indicated; transplant consideration for terminal disease
  • Patient education: activity planning to avoid triggers that increase systemic vascular resistance; dehydration avoidance; alcohol moderation/cessation as relevant (especially in alcoholic CMP)
  • IE prophylaxis remains relevant for CMP patients due to bacteremia risk from procedures; refer to Table 40.2 and Table 40.17 guidance for patient education
  • Multidisciplinary care: involve physicians, nurses, pharmacists, rehabilitation, and family/caregivers; provide emotional and palliative support when appropriate

Key Numerical References and Formulas to Remember

  • IE embolization risk: up to 10.5\%
  • HF prevalence in IE by valve involved: 80\% (aortic valve) and 50\% (mitral valve)
  • Blood culture strategy: 3 cultures drawn over 1 hour from 3 different sites; cultures positive in most IE cases
  • Duke Criteria thresholds: 2 major criteria and 1 minor, or 1 major and 3 minor, or 5 minor
  • Antibiotic therapy duration for IE: typically 4$-$6\text{ weeks}
  • Valve replacement in IE: performed in 50\% to 60\% of cases
  • DCM EF threshold and prognosis: EF < 20\% with ~50\% mortality at 1 year
  • SCD risk in HCM: accounts for 3\% of deaths in young athletes

Prophylaxis and Follow-Up References (Conceptual)

  • Table references in the text (40.1, 40.2, 40.3, 40.17) indicate specific prophylaxis indications, patient education guides, and nursing care checklists
  • Emphasize the importance of oral hygiene, dental care, and prompt treatment of infections to reduce IE risk in CMP patients and other at-risk populations

Summary Takeaways

  • IE is a multi-system infectious process affecting the endocardium/valves with serious complications; early diagnosis using Duke Criteria and aggressive, culture-guided antibiotics, with surgical options for select patients, is critical
  • CMP includes dilated, hypertrophic, and restrictive phenotypes, each with unique etiologies, pathophysiology, and management strategies; HF management and device therapies are central to improving outcomes
  • Takotsubo represents a reversible, stress-related cardiomyopathy that can mimic MI but requires supportive care
  • Across all CMP and IE scenarios, patient education, adherence to therapy, infection prevention, and caregiver involvement are essential to optimize function and quality of life