Heart Failure, Chronic

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Basics

Description

  • Heart failure (HF) is the condition resulting from inability of the heart to fill and/or pump blood sufficiently to meet tissue metabolic needs. Alternatively, HF may occur when adequate cardiac output can be achieved only at the expense of elevated filling pressures. It is the principal complication of heart disease.
  • HF is the preferred term over congestive HF because patients are not always congested (fluid overloaded).
  • HF may involve the left heart, the right heart, or be biventricular. The New York Heart Association (NYHA) classification is a subjective grading scale used for classifying patients with HF: NYHA I: asymptomatic; NYHA II: symptomatic with moderate exertion; NYHA III: symptomatic with mild exertion and may limit activities of daily living; NYHA IV: symptomatic at rest. For acute HF, see “Heart Failure, Acutely Decompensated.”

Epidemiology

The annual direct and indirect cost of HF in the United States is ~$34.4 billion.

Incidence
In the United States, 550,000 new cases diagnosed annually with >250,000 deaths per year

Prevalence
  • ~6.5 million people in the United States have HF; <1% in those age <50 years, increasing to 10% of those age >80 years
  • Primarily a disease of the elderly; 75% of hospital admissions for HF are for persons >65 years of age.

Etiology and Pathophysiology

Two physiologic components explain most of the clinical findings of HF and result in classifications of patients in four general categories:

  • HF with reduced ejection fraction (HFrEF) or systolic HF: an inotropic abnormality, often due to myocardial infarction (MI) or dilated cardiomyopathy (CM), resulting in diminished systolic emptying (ejection fraction [EF] ≤40%)
  • HF with preserved ejection fraction (HFpEF) or diastolic HF: a compliance abnormality, often due to hypertensive CM, in which the ventricular relaxation is impaired (EF ≥50%)
  • Borderline HFpEF (EF 41–49%): mild systolic dysfunction but clinically behaves like HFpEF
  • Improved HFpEF (EF >40%): previously HFrEF but with improvement in systolic function
  • Patients with systolic dysfunction may also have diastolic dysfunction.
  • Most common etiologies: coronary artery disease (CAD)/MI and hypertension (HTN)
  • Myocarditis and CM: alcoholic, viral, long-standing HTN, drugs (e.g., chemotherapeutic agents), muscular dystrophy, infiltrative (e.g., amyloidosis, sarcoidosis), postpartum state, infectious (e.g., Chagas disease, HIV), hypertrophic CM (HCM), inherited familial dilated CM, left ventricular (LV) noncompaction
  • Valvular and vascular abnormalities: any valvular stenosis or regurgitation, rheumatic heart; renal artery stenosis, usually bilateral, may cause recurrent “flash” pulmonary edema, especially in setting of severe chronic HTN.
  • Chronic lung disease and pulmonary HTN (cor pulmonale)
  • Iatrogenic volume overload (requires extreme overload in patients with normal hearts and kidneys)
  • Arrhythmias (atrial fibrillation and other tachyarrhythmias, high-grade heart block)
  • Miscellaneous: high-output states: hyperthyroidism, anemia; cardiac depressants (β-blocker overdose), stress induced
  • Idiopathic: 20–50% of idiopathic dilated cardiomyopathies are familial.
  • HF is progressive—manifested by the remodeling (altered heart geometry) process.

Genetics
Multiple genetic abnormalities responsible for a variety of phenotypes have been identified (HCM, arrhythmogenic right ventricular [RV] dysplasia, LV noncompaction, dilated CM). Consider genetic screening for first-degree relatives of HCM and arrhythmogenic RV dysplasia.

Risk Factors

For development of HF: CAD/MI, HTN (80% of cases of HF in the United States caused by either CAD or HTN), valvular heart disease, diabetes mellitus, cardiotoxic medications (e.g., anthracyclines, tyrosine-kinase inhibitors, TNF-α inhibitors), obesity, older age

General Prevention

Control HTN and other risk factors. Thiazide diuretics and angiotensin-converting enzyme inhibitors (ACE-I) are superior to other agents in preventing development of HF.

Commonly Associated Conditions

Sudden cardiac death and progressive pump failure are the leading causes of death. Most patients have >5 comorbid medical conditions and take >5 medications.

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