|
Snap Shot
  • Dilated cardiomyopathyA 68-year-old male presents to his primary care physician with dyspnea on exertion and swollen ankles. He has a long history of CAD and alcohol abuse. His chest x-ray is shown at right.
Introduction
  • CHF is defined as the inability of the heart to meet the demands of the body
  • Types
    • left-sided (MC)
      • heart cannot pump blood into systemic circulation
      • volume backs up behind the left heart into the pulmonary circulation
    • right-sided
      • heart cannot pump blood into pulmonary circulation
      • volume backs up behind the right heart into the systemic circulation
    • bilateral
    • high-output
      • cardiac output increased compared to resting
  • Cause (left, right, bilateral)
    • systolic dysfunction
      • weakened pumping function of the heart via
        • ischemic heart disease
        • chronic hypertension
        • cardiomyopathy (viral or idiopathic) in younger patients
    • diastolic dysfunction 
      • inability of the heart to relax/fill via
        • hypertension with LVH (most common cause)
        • hypertrophic cardiomyopathy
        • amyloidosis
        • sarcoidosis
        • hemochromatosis
        • scleroderma
        • post-operative/radiation fibrosis
    • valvular dysfunction
    • arrhythmias
  • Cause (high-output)
    • changes in blood flow factors
      • ↓ blood viscosity as seen in severe anemia
      • peripheral resistance as seen in endotoxic shock
      • ↑ blood return to heart as seen in AV fistula 
      • ↑ cardiac output as seen in hyperthyroidism
  • Precipitating factors
    • acute MI
    • long-standing HTN
    • chronic anemia
    • acute and/or recurrent pulmonary embolism
    • chronic endocarditis
    • post-partum females
    • thyrotoxicosis
  • Risk factors
    • CAD
    • family history of hypertrophic cardiomyopathy
    • HTN
    • valvular heart disease
    • ETOH abuse 
    • myocarditis
    • drug side effects (i.e. doxorubicin)
Presentation
  • Symptoms
    • patients suffering from CHF can present with a wide range of symptoms that help identify the affected side of the heart as follows 
      • left-sided failure (forward failure)
        • exertional dyspnea
        • orthopnea
        • paroxysmal noctural dyspnea
          • choking sensation when supine
          • relieved by sitting up/standing
          • caused by an increase in blood return to left heart when not pumping against gravity
        • persistent coughing due to pulmonary edema
          • pink/frothy sputum
          • alveoli contain hemosiderin-filled macrophages
            • "heart-failure cells" 
        • may progress to concomitant right-sided failure
      • right-sided failure (backwards failure)
        • abdominal fullness
        • exertional dyspnea
        • ankle-swelling
        • increased levels of atrial natriuretic peptide (ANP)
  • Physical exam
    • left-sided failure
      • bibasilar crackles
      • diffuse, left-displaced PMI
      • Cheyne-Stokes respiration
      • S3 heart sound (early diastolic)
        • first sign of left or right failure  
        • intensity increases with expiration
        • in left heart failure, S3 is best heard with bell of stethoscope with patient in left lateral decubitus position
      • may hear mitral regurgitation murmur
        • a result of ventricle dilation stretching the valve ring
    • right-sided failure
      • atrial fibrillation
      • JVD
      • S3 heart sound (early diastolic)
        • intensity increases with inspiration
      • may hear tricuspid regurgitation murmur
        • a result of ventricle dilation stretching the valve ring
      • hepatomegaly
        • result of blood flow backing up into liver
      • lower-extremity pitting edema + ascites
Evaluation
  • Mainly a clinical diagnosis
  • Serological
    • brain natriuretic peptide (BNP) and atrial natriuretic peptide (ANP)
      • released by the ventricles and the atria in response to increased stretch
      • both elevated in patients with heart failure and can be used to determine if acute dyspnea is caused by heart failure or another etiology
      • nesiritide is a recombinant form that has been used in the treatment of CHF
  • Imaging
    • chest x-ray
      • an important test to assess for severity of left heart failure
Treatment
  • Acute cases
    • if the patient has worsening dyspnea and other symptoms then
      • diurese aggressively
      • use ACE inhibitors in all patients who can tolerate them
      • dobutamine for inotropy
      • nitroprusside for afterload reduction.
  • Chronic cases
    • lifestyle modifications
      • limit dietary sodium intake
    • medications
      • ACE inhibitors are first-line have been shown to improve survival
      • digitalis and diuretics improve symptoms but not proven to improve survival
      • warfarin indicated with
        • severe dilated cardiomyopathy
        • atrial fibrillation
        • previous embolic episode
      • maintenance medications include
        • B-blockers 
        • afterload reduction via ACEi/ARB
        • spironolactone if K level is not high
        • hydralazine and long-acting nitrates (eg. isosorbide dinitrate) in African-Americans
      • arrhythmia medications
        • treat arrhythmias as they arise
  • Exacerbations (in chronic patients) 
    • treat with loop diuretics such as furosemide when patient is volume-overloaded
  • Treat/control underlying etiologies if identified and possible
    • such as thyrotoxicosis, anemia, CAD, HTN, etc.
    • *avoid overdiuresis
 

Please rate topic.

Average 4.9 of 9 Ratings

Questions (10)
EVIDENCE & REFERENCES (14)
VIDEOS (1)
Topic COMMENTS (18)
Private Note