Congestive Heart Failure

Snapshot

  • A 70-year-old woman presents to the emergency room for shortness of breath. She has a past medical history of hypertension, type 2 diabetes mellitus, coronary artery disease, and alcohol use disorder. On physical exam, she has jugular venous distention, pulmonary rales, cardiac S3 sound, and pitting edema. Her electrocardiogram shows sinus tachycardia and chest radiograph shows pleural effusions and cardiomegaly. She is immediately given a loop diuretic and oxygen.  

Introduction

  • Clinical definition
    • inability of the heart to pump blood throughout the body, leading to congestion and decreased perfusion
      • systolic dysfunction
        • loss of contractile strength and results in low ejection fraction (< 45%)
      • diastolic dysfunction  
        • impairment in filling of the heart and often has a normal ejection fraction
      • high-output heart failure
        • occurs in a minority of patients
        • cardiac output exceeds metabolic demand
      • decompensated heart failure
        • occurs when symptoms are worsened or exacerbated
        • precipitating factors include 
          • infections 
          • arrhythmias
          • excessive salt in the diet (post-holiday heart)
          • uncontrolled hypertension
          • thyrotoxicosis
          • myocardial infarction
  • Epidemiology
    • risk factors 
      • coronary artery disease
      • viral infection
      • alcohol abuse
      • hypertension
      • arrhythmias
      • metabolic syndrome
      • drugs (e.g., doxorubicin)
      • smoking
  • Etiology
    • systolic dysfunction 
      • ischemic heart disease (most common)
      • chronic hypertension
      • dilated cardiomyopathy
      • valvular disease 
      • congenital heart disease
    • diastolic dysfunction 
      • hypertension with left ventricular hypertrophy
      • hypertrophic cardiomyopathy
      • amyloidosis
      • sarcoidosis
      • hemochromatosis 
      • scleroderma
      • post-operative/radiation fibrosis
    • high output heart failure
      • obesity
      • myeloproliferative disorder
      • arterial-venous fistula 
      • thyrotoxicosis
  • Pathogenesis
    • systolic dysfunction  
      • ↓ contractility leading to ↓ ejection fraction and ↑ end diastolic volume
      • ↑ systemic vascular resistance
      • most commonly due to dilated cardiomyopathy and ischemic heart disease
      • induces a state of hypoperfusion leading to compensatory activation of the sympathetic nervous system and renin release from the juxtaglomerular apparatus 
        • increased levels of renin, angiotensin, and aldosterone
        • vasoconstrictive effect of angiotensin II causes increased peripheral resistance
        • mineralocorticoid effects of aldosterone causes fluid retention and metabolic alkalosis
    • diastolic dysfunction
      • ↓ compliance leading to problems with relaxation and filling of the heart
      • normal ejection fraction and normal end diastolic volume
      • most commonly due to myocardial hypertrophy
    • right heart failure most commonly results from left heart failure
    • high output heart failure
      • high cardiac output and ↓ systemic vascular resistance
      • often occurs in the setting of existing systolic or diastolic dysfunction
  • Associated conditions
    • obstructive sleep apnea
  • major depression disorder

Presentation

  • Symptoms  
    • dyspnea on exertion
    • orthopnea
    • paroxysmal nocturnal dyspnea
    • fatigue
    • pulmonary edema
    • dysphagia
      • due to enlargement of the left atrium 
  • Physical exam 
    • cardiovascular exam
      • pitting lower extremity edema
      • jugular venous distention
      • S3 sound 
    • pulmonary exam
      • Cheyne-Stokes respiration  
      • shortness of breath
      • rales  
        • liquid accumulates in alveoli due to left heart pressure overload
        • alveoli pop open during inhalation, causing rales on exam
    • abdominal exam 
      • ascites
  • hepatojugular reflex

Imaging

  • Chest radiograph
    • findings 
      • pulmonary vascular congestion
      • pleural effusion
      • cardiomegaly
      • Kerley-B lines
      • interstitial edema
  • Echocardiogram
    • indications
      • confirms the diagnosis of heart failure
      • classifies whether heart failure is due to systolic or diastolic dysfunction
    • findings
      • assess for low ejection fraction
      • systolic of diastolic dysfunction
      • systolic heart failure is characterized by
        • decreased cardiac index
        • increased systemic vascular resistance
  • increased left ventricular end diastolic pressure

Studies

  • Atrial and B-type (brain) natriuretic peptide (ANP and BNP)   
    • released by the ventricles and the atria in response to increased stretch
    • elevated levels are often seen in decompensated CHF
    • normal BNP excludes a diagnosis of CHF
  • Electrocardiogram (ECG)
    • findings
      • sinus tachycardia
      • may also have arrhythmias
      • may show ventricular hypertrophy
  • Making the diagnosis
  • based on clinical presentation and echocardiogram

Differential

  • Acute respiratory distress syndrome
    • distinguishing factors
      • diffuse crackles in the lungs, no S3 heart sound, and increased work of breathing on exam
  • chest radiograph with bilateral alveolar infiltrates

Treatment

  • Management approach
    • mortality is decreased with angiotensin-converting enzyme inhibitors (ACE-inhibitors) or angiotensin II receptor blockers (ARBs), β-blockers, and spironolactone or eplerenone 
  • Conservative
    • avoid excessive salt in the diet
      • indication
        • all patients
  • Medical
    • ACE-inhibitors or ARBs
      • indications
        • lowers mortality
        • systolic or diastolic dysfunction
    • hydralazine and nitrates
      • indications
        • systolic dysfunction
        • when ACE-inhibitors or ARBs are contraindicated, such as in those with renal failure
    • β-blockers 
      • indications
        • lowers mortality
        • systolic or diastolic dysfunction
      • drugs
        • metoprolol
        • carvedilol
        • bisoprolol
    • spironolactone or eplerenone  
      • indication
        • lowers mortality
        • systolic or diastolic dysfunction
      • side effects
        • spironolactone has anti-androgen effects such as erectile dysfunction and gynecomastia in men
        • hyperkalemia
    • diuretics   
      • indications
        • pulmonary edema
        • CHF exacerbations
        • lower extremity edema
        • systolic or diastolic dysfunction
      • drugs  
        • loop diuretics
        • thiazide diuretics
    • digoxin
      • indications
        • severe systolic dysfunction
        • as an inotrope, it does not improve mortality, but it does reduce hospitalizations
    • milrinone  
      • indications
        • acute cardiogenic shock
        • decompensated heart failure
      • side effects
        • hypokalemia
        • bronchospams
  • tremors

Complications

  • CHF exacerbation
  • Cardiac arrhythmias
  • Respiratory failure