Week 6: Inflammatory and Structural Heart Disorders

Infective Endocarditis

• An infection of the endocardium, which lines the heart and forms the heart valves.

  • Commonly caused by bacteria (e.g., staphylococci, enterococci) but can also be due to fungal infections.

• Endocardium (inner lining covering trabeculae; they form the valves)

Causes of Infective Endocarditis

• Use of shared needles

• Direct contamination

• Surgical or dental procedures

• Development from a systemic infection.

Pathophysiology of Infective Endocarditis

• Colonization of microbes occurs at sites of abnormalities or injuries (e.g., prolapsing valves, injured valves, or artificial valves).

• The inflammatory response leads to endothelial damage, promoting clustering of platelets, fibrin, white blood cells (WBCs), and bacteria (a vegetation). This forms around the valves. Can be a viral or fungal infection.

• Vegetations form on the endocardium:

  • Fragile and easily crumbled, can break off, causing emboli.

  • Can damage valve leaflets and mechanical valves, leading to abscess formation.

Risk Factors for Infective Endocarditis

• Pre-existing heart disease.

• Intravenous (IV) drug use.

• Cardiac valvular diseases.

  • Rheumatic heart disease.

  • Presence of prosthetic valves.

  • Congenital and structural abnormalities (e.g., mitral valve prolapse).

    • Common valve replacements: aortic valve (blood from the left ventricles to the rest of the body) and mitral (between the left atrium and left ventricle).

      • Mechanical replacements, the client needs to be on anticoagulation therapy, and you’ll hear a click upon auscultation.

      • Biological ones, which come from animals, deteriorate more quickly.

• Long-term intravenous catheters.

• Recent body piercings or similar procedures.

Manifestations of Infective Endocarditis

• Symptoms:

  • Rapid onset with fever and chills.

  • Subacute presentations with gradual onset, low-grade fever, and constitutional symptoms.

  • Notable signs include heart murmurs, worsening with vegetation damage.

  • General symptoms may include myalgias and joint pain. Fever is not mandatory.

• Specific Signs:

  • Splinter Hemorrhages and Petechiae (occurring in ~40% of cases due to hemorrhage from distal capillaries).

    • Petechiae: common in those with low platelets/thrombocytopenia.

  • Osler Nodes: Painful, red nodules in fingers/toes due to microemboli.

  • Janeway Lesions: Painless red or purple macules on palms or soles.

Risks for Infective Endocarditis

• Left-sided heart embolizations can impact major organs (e.g., brain, kidneys, liver, spleen).

• Right-sided heart embolizations primarily affect the lungs.

Management for Infective Endocarditis

• Antibiotics for treating infections.

  • Obtain a blood culture to diagnose and determine how to treat the infection.

• Monitoring for local valve damage and potential complications: sepsis, heart failure, and heart block.

Acute Pericarditis

• Inflammation of the pericardium, the protective sac around the heart.

  • Holds the heart in place.

  • Baroreceptors control heart rate and BP.

• Pericardium structure:

  • Composed of:

    • Fibrous Pericardium (outer layer)

    • Serous Pericardium:

      • Parietal layer (outer)

      • Visceral layer (inner; epicardium)

    • Contains 15-50 ml of pericardial fluid to reduce friction.

Causes of Acute Pericarditis

• Can be caused by infections (bacterial, viral, fungal) or secondary to inflammation from:

  • Myocardial infarction (MI)

  • Cardiac surgery

  • Malignancy

  • Lupus

• 80% of cases are idiopathic, often thought to be viral.

• Risk of pericardial effusion leading to cardiac tamponade (pressure on the heart). Constrictive pericarditis can occur, restricting heart movement and filling, leading to decreased cardiac output.

  • It smoothers the heart with too much fluid.

  • Tamponade: a medical emergency characterized by the accumulation of fluid in the pericardial space, which can significantly impair the heart's ability to pump effectively and requires immediate intervention.

Manifestations of Acute Pericarditis

• Symptoms range from mild to severe.

• Common symptom: Chest pain (similar to MI) characterized as:

  • Sharp

  • Aggravated by deep breaths, coughing, and lying down (indicative sign!).

  • Persistent nature, with relief upon sitting or leaning forward.

  • Retrosternal pain that can radiate.

• Signs include:

  • Friction Rub: A distinctive heart sound arising from the rubbing of inflamed pericardial layers.

  • Commonly heard at the left lower sternal border (4th intercostal space) using the diaphragm of the stethoscope, loudest when the patient sits forward.

• Other symptoms:

  • Fever

  • Increased white blood cell (WBC) count

  • Elevated sedimentation rate/C-reactive protein

  • Exertion-independent dyspnea

  • Widespread ST-segment elevation on 12-lead EKG

  • Possible pericardial effusion on echocardiogram.

Management for Acute Pericarditis

• Aim to relieve pain and manage symptoms.

• Assess for cardiac tamponade signs.

• First-line treatments include NSAIDs (e.g., Ibuprofen, ASA, Indomethacin).

  • Given anti-inflammatories.

• Corticosteroids are used for patients intolerant to NSAIDs, and colchicine for recurrent cases.

• Positioning is key for comfort, providing reassurance that the symptoms are not indicative of a heart attack.

  • Relieved with sitting and leaning forward to reduce pressure from the parietal pericardium.

Stenosis

• Narrowing of valve openings, reducing blood flow through the valve.

  • It doesn’t fully open or close all the way.

Regurgitation

• Incomplete closure of valves, allowing backward blood flow.

Mitral Valve Disorders

• Mitral Valve Stenosis: Constriction of the mitral valve.

• Mitral Valve Regurgitation: Backflow of blood into the left atrium due to improper valve closure.

• Mitral Valve Prolapse: The mitral leaflets bulge backward into the left atrium, causing regurgitation.

  • Limited to the mitral valve.

  • Common in women.

  • The mitral valve can be replaced if this issue cannot be fixed.

  • The leaflet folds downward/dips (hooding) into the left atrium during systole, which can lead to mitral regurgitation if the valve does not close properly.

Aortic Valve Disorders

• Aortic Stenosis and Regurgitation: Aortic stenosis involves narrowed openings; regurgitation features leakage back into the left ventricle when the valve fails to close completely.

  • Regurgitation usually follows stenosis or prolapse, as it is present in relation to issues of the valve.

Diagnositcs for Vavular Heart Diseases

• Electrocardiogram (EKG)

• Chest X-ray

• Echocardiogram (including Transesophageal Echocardiogram/TEE)

  • 3D Doppler echocardiography

• Cardiac catheterization

• Exercise stress test.

Management for Valvular Heart Disease

• Conservative Treatments:

  • Medications and rest.

  • Percutaneous trans-luminal balloon valvuloplasty (replacement/repair of the valve): a minimally invasive procedure (percutaneously or surgically) used to open narrowed heart valves by inserting a balloon through a catheter and inflating it to widen the valve opening.

    • Annuloplasty: repair of the outer ring around the valve.

• Surgical Treatments:

  • Valve repair and replacement.

  • Cardiac transplant in severe cases.

• Prosthetic Valve Types:

  • Mechanical (e.g., bi-leaflet, caged-ball)

  • Tissue valves (e.g., homograft, pericardial, xenograft).

Post-Op Care for Valve Repair/Replacement

• Monitoring for signs/symptoms of emboli and heart failure.

• Care aligns with postoperative protocols for patients recovering from coronary artery bypass surgery.

• High risk of post-op complications (thromboembolism, infection, arrhythmias, hemolysis).

Cardiomyopathy

• A group of disorders involving the myocardium, leading to mechanical and/or electrical dysfunction.

  • Dilated Cardiomyopathy (DCM)

  • Hypertrophic Cardiomyopathy (HCM)

    • Can be seen in children.

  • Restrictive Cardiomyopathy (RCM): Rigid heart muscle restricting filling.

  • Arrhythmogenic Right Ventricular Cardiomyopathy (ARVC): Replacement of heart muscle cells with fat and scar tissue.

    • Temporary, broken heart as the muscles are weakened for a while.

  • Stress-Induced Cardiomyopathy: Typically resolves in weeks.

• Results in impaired cardiac output.

Dilated Cardiomyopathy

• Weakened and enlarged left ventricle.

• Results in thinning of the left ventricular wall and increased chamber size and volume.

  • An over-stretched rubber band that doesn’t fling back the way it normally does.

Hypertrophic Cardiomyopathy

• A genetic condition resulting in a thickened left ventricular wall.

  • Can be seen in children.

• Characterized by left ventricular hypertrophy, thickening, impacting heart's ability to pump efficiently.

  • The muscle is overworked, causing this growth/hypertrophy.