Disorders of the Heart Wall Notes

Disorders of the Heart Wall

• Cardiovascular disease is the leading cause of death and disability.
• Clinicians need to identify and rapidly respond to clients with cardiovascular alterations.
• Understanding cardiopulmonary circulation is essential.

Heart Wall Layers

• Module organizes content related to cardiac structure and function.
• Layers:
  • Pericardium
  • Myocardium
  • Endocardium
• Content flow: heart wall disorders including valves, inflammatory/infectious conditions, and dysrhythmias.
• Cardiac output is a concern common to alterations of cardiac function.

Acute Pericarditis

• Pericardial inflammation of < 2 weeks of primary or systemic origin.
• Clinical Manifestations
  • EKG Changes – injury pattern
  • Chest pain – worse when supine, deep breathing, coughing; eased when leaning forward
  • Pericardial friction rub – systole and diastole
  • Lab Changes - Elevated WBC, ESR, sometimes CRP

Pericardial Effusion & Cardiac Tamponade

• Fluid in pericardial sac surrounding the heart.
• Fluid compresses heart contraction.
• Limits venous return to the heart.
• 50-100 ml can significantly decrease cardiac output.
• Clinical manifestations
  • Dull distant heart sounds
  • Weakly palpable apical pulse
  • Chest pain worse when supine
  • Exertional dyspnea

Infective Endocarditis

• Incidence greatly increased due to intravenous drug use.
• Other risk factors
  • Prosthetic heart valve
  • Pacemaker
  • Previous history of IE
  • Long-term IV catheterization
  • Staphylococcus aureus from skin is most common organism.
• Heart Valve Damage

Cardiomyopathy

• Common etiologies include:
  • Diabetes mellitus
  • Thyrotoxicosis
  • Chemotherapy
  • Pregnancy
  • Sleep apnea
  • Toxins – alcohol, abused stimulant drugs

Cardiomyopathy - Dilated

• Ventricle hypertrophy is common feature of heart failure, with cardiomyopathy dilation of chambers produces thinning rather than thickening of the heart walls.
• Rapid deterioration of myocardium
• Severely impaired systolic function
• Ischemic heart disease
• Valvular heart disease
• Effects:
  • Decreased myocardial contractility
  • Decreased systolic emptying

Cardiac Valve Disorders - Types

• May be congenital or acquired with acquired types more common in adults.
• Worldwide, most common acquired causes are degeneration and infection of the endocardium due to rheumatic heart disease.
• In US, age-related valve degeneration is most common etiology.
• Regurgitation - also called incompetence or insufficiency
  • Inability of valve leaflets to close properly
  • Blood leaks backward into emptying chamber
  • Increased volume in chamber increases workload and leads to hypertrophy
• Stenosis
  • Narrowed opening
  • Heart is unable to eject blood from chambers
  • Blood can’t flow forward as normal
  • Increased volume in chamber increases workload and increases hypertrophy

Cardiac Valve Disorders - Pathophysiology

• Turbulent blood flow across cardiac valves is source of auscultated murmur.
• Instead of the usual antegrade (forward) movement, blood flow also includes retrograde movement and/or becomes obstructed.
• Decreased ventricular filling leads to decreased stroke volume.
• Reduced stroke volume leads to decreased cardiac output.

Mitral Valve Prolapse Syndrome

• Most common valve disorder in the US.
• Degenerative weakening of valve connective tissue.
• Valve leaflets bulge (prolapse) upward, into the left atrium
• Most common cause of mitral regurgitation when blood leaks into the left atrium.
• Many individuals are asymptomatic.
• Murmur prompts echocardiogram.
• When symptoms, they can be vague and confusing:
  • Palpitations, dizziness, fatigue, atypical chest pain
  • Depression, anxiety, panic attacks
  • May be associated with hyperthyroidism

Mitral Valve Regurgitation

• Causes include:
  • Mitral valve prolapse
  • Endocarditis
  • Myocardial infarction
  • Chordae tendonae damage
  • Rheumatic heart disease
  • Connective tissue disease
• Backflow of blood from left ventricle into left atrium during systole.
• Heart failure is eventual outcome.
• Atrial fibrillation can occur due to altered cardiac conduction through left atrium.

Aortic Stenosis

• Most often diagnosed cardiac valve disease.
• Causes include bicuspid valve, age-related degeneration, and rheumatic heart disease.
• Valve opening is narrowed.
• Left ventricle works harder to push blood across the valve into the aorta.
• Leads to left ventricular hypertrophy then heart failure with decreased cardiac output and pulmonary congestion.

Acute Rheumatic Fever

• Diffuse inflammatory disease due to delayed immune response to infection by the group A β-hemolytic streptococci.
• Abnormal humoral and cell-mediated response to a protein on the bacterial that causes cross-reaction with normal tissue such as heart cells and valves.
• Only occurs with pharyngeal infection.
• Individual has a genetic predisposition.
• Febrile illness - Inflammation of the joints, skin, nervous system, and heart.
• If left untreated, rheumatic fever causes rheumatic heart disease.

Rheumatic Heart Disease

• Untreated rheumatic fever
• Scarring and deformity of cardiac structures
• Valve leaflet destruction
• Clinical Manifestations
  • Carditis
  • Polyarthritis
  • Chorea
  • Erythema marginatum – transient non-itchy pink rash on trunk that spreads outward