Rosen & Barkin's 5-Minute Emergency Medicine Consult (134 page)

Various causes are suggested but remain unproved:

• Viral infection leading to myocarditis in presence of immunosuppression during pregnancy (
  most likely
  )
  
• Immunologic response to an unknown maternal or fetal antigen
  
• Maladaptive response to the hemodynamic stresses of pregnancy
  
• Stress-activated cytokines
  
• Prolonged tocolysis
  
• Selenium deficiency
  

DIAGNOSIS

• Dyspnea
  
• Dizziness
  
• Chest pain
  
• Orthopnea
  
• Cough
  
• Paroxysmal nocturnal dyspnea
  
• Anorexia
  
• Fatigue
  
• Arrhythmias
  

• Onset and duration of symptoms
  
• Unexplained persistent cough
  
• Excessive weight gain:
  
  • >2–4 lb/wk
    
• Prior cardiac disease
  
• Prior pregnancies and complications
  

• Palpitations
  
• Jugular venous distention
  
• Gallop rhythm
  
• Mitral regurgitation murmur
  
• Loud P2
  
• Pulmonary rales
  
• Peripheral edema (especially rapid onset)
  
• Hepatomegaly
  
• Hepatojugular reflux
  

• CXR views:
  
  • Pulmonary venous congestion
    
  • Cardiomegaly (can be difficult to differentiate with pregnancy)
    
  • Pleural effusions
    
• EKG:
  
  • Nonspecific
    
  • Left ventricular hypertrophy
    
  • Left atrial enlargement
    
  • T-wave flattening or inversion
    
  • Arrhythmias
    
  • Ventricular ectopy (40%)
    
  • Atrial fibrillation (20%)
    

• Electrolytes:
  
  • Generally normal
    
• BUN, creatinine
  
• CBC:
  
  • Mild postpartum anemia may contribute to fatigue and dyspnea.
    
• Creatine kinase with muscle and brain fraction
  
• β-Natriuretic peptide (BNP):
  
  • Useful for distinguishing between heart failure due to diastolic and/or systolic dysfunction and a pulmonary cause of dyspnea
    
  • BNP >100 pg/mL diagnosed heart failure with a sensitivity of 90%, a specificity of 76%, and a predictive accuracy of 83%. BNP of ≤50 pg/mL has a high negative predictive value.
    

• CXR:
  
  • Cardiomegaly
    
  • Effusions (usually right sided)
    
  • 3 phases of pulmonary findings:
    
    • Stage I: Pulmonary redistribution to upper lung fields (cephalization)
      
    • Stage II: Interstitial edema with Kerley B lines
      
    • Stage III: Alveolar edema
      
    • Bilateral confluent perihilar infiltrates leading to classic butterfly pattern
      
    • May be asymmetric and mistaken for pneumonia
      
• Echo:
  
  • Demonstrates global dilation, cardiac wall thinning, and decreased ejection fraction
    
  • Criteria for the diagnosis were established by Hibbard et al.:
    
    • Ejection fraction <45% or M-mode fractional shortening of <30%
      
    • End-diastolic dimension >2.72 cm/m
      ²
      
  • Exclude valvular pathology and cardiac tamponade.
    

Endomyocardial biopsy:

• Indicated to assess for myocarditis and steroid therapy
  

• Other causes of dilated cardiomyopathy:
  
  • Ischemia
    
  • Infarction
    
  • Valvular rupture or disease
    
  • Chronic HTN
    
  • Familial
    
  • Toxins:
    
    • Ethanol, anthracyclines, cocaine, drug allergy
      
  • Metabolic:
    
    • Thiamine
      
    • Selenium
      
    • Hypothyroidism
      
    • Thyrotoxicosis
      
    • Hypophosphatemia
      
  • Infectious:
    
    • Viral
      
    • Parasitic or rickettsial
      
    • Bacterial
      
    • Fungal
      
  • Systemic disorders:
    
    • Sarcoidosis
      
    • Scleroderma
      
    • Systemic lupus erythematosus
      
  • Eosinophilic myocarditis
    
  • Neuromuscular dystrophies
    
  • Mitochondrial cardiomyopathies
    
• Other causes of shortness of breath or edema:
  
  • Pulmonary embolism
    
  • Pneumonia
    
  • Asthma
    
  • Cardiac ischemia
    
  • Anemia
    
  • Hyperthyroidism
    
  • Constrictive pericarditis
    
  • Pericardial tamponade
    
  • Nephrotic syndrome
    
  • Cirrhosis
    

TREATMENT

Differentiate pulmonary edema from acute reactive airway disease.

ABCs:

• Prompt evaluation of respiratory and hemodynamic status
  
• Control airway as needed
  
• Supplemental oxygen
  
• Continuous positive airway pressure, as needed
  
• Preload and afterload reduction
  

• Antepartum therapy:
  
  • Nitrates
    
  • Hydralazine
    
  • IV furosemide
    
  • Amlodipine: A dihydropyridine calcium channel blocker that has been shown to improve survival in nonischemic cardiomyopathy patients
    
  • Digoxin to control rate due to atrial fibrillation
    
  • Carvedilol (antepartum and not in acute decompensated phase)
    
  • LMWH if EF <35%
    
  • Fetal monitoring
    
• Invasive cardiac monitoring if unstable
  
• Postpartum therapy:
  
  • Consider adding ACE inhibitors (enalapril) or ARBs.
    
  • Anticoagulation therapy often recommended:
    
    • 30% of cases complicated by systemic or pulmonary embolism
      
    • During pregnancy, use SC or IV heparin rather than warfarin, which causes birth defects.
      
• For severe symptoms or lack of response to standard therapy:
  
  • Dobutamine
    
  • Dopamine
    
  • Nitroprusside
    
  • Assist devices
    
    • Intra-aortic balloon pump
      
    • LV assist device
      
    • Extracorporeal membrane oxygenation
      
  • Immunosuppressive therapy:
    
    • Advocated for patients who fail to improve within 2 wk of standard medical therapy
      
    • Prednisone with cyclosporine or azathioprine
      
    • Immunoglobulin therapy remains controversial
      

• Amlodipine: 2.5–10 mg/d PO
  
• Bumetanide: 0.5–2 mg IV
  
• Digoxin: 0.5 mg IV, then 0.25 mg IV q4h for 2 doses; 0.125–0.375 mg/d PO
  
• Milrinone: 50 μg/kg over 10 min
  
• Dobutamine: 2–10 μg/kg/min IV
  
• Dopamine: 2–20 μg/kg/min IV
  
• Enalapril: 0.625–1.25 mg IV; 2.5–20 mg/d PO
  
• Furosemide: 20–100 mg IV
  
• Metoprolol: 12.5 mg PO BID
  
• Morphine sulfate: 2–4 mg IV q5min
  
• Nitroglycerin: 0.4 mg sublingual; 1–2 in of nitroglycerin paste; 5–20 μg/min IV, max. of 100–200 μg/min IV. USE NON-PVC tubing
  
• Nitroprusside: 0.5–10 μg/kg/min IV
  

FOLLOW-UP

• Patients with pulmonary edema, cardiogenic shock, or evidence of ischemia should be admitted to the ICU.
  
• All symptomatic patients with new onset of peripartum cardiomyopathy should be admitted.
  

• Mild left ventricular dysfunction
  
• Established history of peripartum cardiomyopathy:
  
  • Mild fluid overload attributable to excessive salt intake
    
  • Complete resolution of symptoms following ED treatment
    
  • No evidence of cardiac ischemia
    
• Close follow-up arranged
  

Close follow-up with a cardiologist

• Drink 6–8 glasses of liquid each day.
  
• Limit salt intake.
  
• Avoid alcohol because it may worsen cardiomyopathy.
  
• Support socks may help decrease the swelling in legs and prevent clot formation.
  
• Daily weights:
  
  • Weight gain can be a sign of extra fluid in the body.
    
  • Call doctor if gain of >2 lb in a day.
    
• Return for shortness of breath, feeling faint, palpitations.
  

• Remember high rates of thromboembolism in pregnancy and peripartum cardiomyopathy.
  
• Utilize multidisciplinary approach with cardiology and obstetrics consultations.
  

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