Heart Failure

Basics

Description

  • CHF, now referred to simply as “heart failure” (HF), is a heterogeneous clinical syndrome resulting from either impaired filling or ejection of blood from the ventricle
  • HF often results in progressive debility, episodes of acute decompensation
  • High (>50%) 5-yr mortality
  • Affects ∼5.1 million Americans
  • Estimated 2013 cost of CHF is >$30 billion
  • Leading Medicare diagnosis for hospitalized patients ≥65 yr old
  • Acute decompensated heart failure (ADHF): Acute onset of new or worsening symptoms of HF (hr–days)
    • Common reason for presentation to the ED:
      • 70% are recurrent exacerbations of chronic HF
      • 15% are new diagnosis of HF
      • 5% end-stage/terminal event
    • ADHF may result from worsening cardiac pump function, or from changes in preload or afterload:
      • Precipitating events include rapid increase in sympathetic tone, concomitant illness, arrhythmia, myocardial ischemia, progressive valve disease, intravascular volume increase
    • 4 common phenotypical presentations based on adequacy of perfusion (warm versus cold) and presence of congestion (wet vs. dry)
  • Chronic HF is a progressive failure state (mo–yr) characterized by structural and functional changes, with two main subclasses:
    • Heart failure with reduced ejection fraction (HFrEF):
      • Impaired contractility or pump function causing decreased ejection fraction (EF <40%)
      • Estimated prevalence 50%
      • Many have concomittent diastolic dysfunction
    • Heart failure with preserved ejection fraction (HFpEF) EF >50%
      • Impaired ventricular relaxation and compliance resulting in decreased cardiac filling
      • More common in older patients, women, patients with HTN
  • ACCF/AHA stages: Progressive stages denote nonreversible cardiac dysfunction. A–D, where A = risk but no disease, and D = refractory HF
  • NYHA classification: Functional classes I–IV, where I has no limit on physical ability and IV has symptoms of HF at rest. Patients may improve class with therapy

Etiology

Underlying causes and acute precipitants:
  • HF may result from disorders of the heart valves, endocardium, myocardium, pericardium, and metabolic derangements
  • Decreased myocardial contractility:
    • Ischemic cardiomyopathy
    • Nonischemic cardiomyopathies:
      • Familial, obesity, diabetic
      • Endocrine: Hypothyroid, acromegaly,
      • Pregnancy-related dilated CMP
      • Toxin-related (alcohol, cocaine, chemotherapy)
      • Inflammatory: Infectious and noninfectious myocarditis (viral, Chagas, SLE, HIV)
      • Tachycardia-induced
      • Amyloidosis
      • Cardiac sarcoidosis
  • Increased pressure states:
    • HTN
    • Valvular abnormalities
    • Congenital heart disease
    • RH failure due to pulmonary hypertension: Primary PAH, OSA, COPD, CTEPH, IPF, and others
    • Pulmonary embolism
  • Volume overload:
    • Dietary indiscretion (sodium overload)
    • Drugs leading to sodium retention (glucocorticoids, NSAIDs)
    • Overload due to transfusion or IV fluid
  • High demand states:
    • Hyperthyroidism, thyrotoxicosis
    • Pregnancy
    • A-V fistula
    • Beriberi (thiamine deficiency)
    • Paget disease
    • Severe anemia
    • Aortic insufficiency
  • Pediatric etiologies: Volume/pressure overload lesions vs. acquired HD:
    • First 6 mo: VSD and PDA
    • Older children: Subvalvular aortic stenosis, coarctation
    • Acquired dysfunction: Nonspecific age of onset, including myocarditis, valvular disease, and cardiomyopathies; cocaine/stimulant abuse in adolescents

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