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    Cardiomegaly –Diagnosis


    Last Updated May 07, 2021
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    By Julian Marsden, Melissa Lee


    Cardiomegaly is suggested via ECG criteria or imaging findings:

      • Cardiothoracic ratio >50 % on a posterior-anterior chest x-ray or CT.

    • Cardiomegaly etiology is numerous and complex with both genetic and non-genetic components.
    • Cardiomegaly is associated with a spectrum of clinical heart failure syndromes.
    • The critical pathophysiological changes include dilated hypertrophy, fibrosis, and contractile malfunction leading to heart failure.
    • Heart failure has a 5-year 50% mortality rate.


    • Numerous etiologies of dilated or hypertrophic cardiomyopathy:
      • Coronary artery disease.
        • myocardial infarction.
        • ischemia.
      • Hypertensive heart disease.
      • Valvular heart disease.
      • Congenital heart disorders:
        • Atrial septal defect.
        • Ventricular septal defect.
        • Patent ductus arteriosus.
        • Tetralogy of Fallot.
        • Coarctation of the aorta.
      • Pulmonary disease:
        • Primary pulmonary hypertension.
        • COPD.
        • Obstructive sleep apnea.
        • Pulmonary embolism.
      • Infection: viral, HIV, Chaga disease.
      • Infiltrative disease: amyloidosis, sarcoidosis, acromegaly, and hemochromatosis.
      • Toxins: alcohol, cocaine, chemotherapeutic agents.
      • Arrhythmia: atrial fibrillation and flutter.
      • Systemic disease: anemia, hypo/hyperthyroidism, vitamin B1 deficiency, AV fistula.
      • Physiologic: stress cardiomyopathy, exercise-induced cardiomegaly, and pregnancy.
      • Familial cardiomyopathy.
      • Idiopathic.

    Clinical Presentation


    • Many are asymptomatic.
    • Symptoms:
      • Dyspnea on exertion/rest, orthopnea, and paroxysmal nocturnal dyspnea.
      • Peripheral edema and abdominal distension.
      • Fatigue and poor exercise tolerance.
      • Palpitations, light-headedness, and/or syncope.
      • Angina.
      • Anorexia, nausea, and early satiety.
    • Family history of cardiomyopathy or cardiovascular disease.

    Physical exam:

    • Sinus tachycardia.
    • Diminished pulse pressure.
    • Respiratory distress.
    • Cool, cyanotic extremities.
    • Jugular venous distension.
    • Ascites, hepatomegaly and peripheral edema.
    • Pulmonary crackles.
    • Murmur.
      • S3 gallop in early diastole (systolic dysfunction).
      • S4 gallop in late diastole (diastolic dysfunction).
    • Displaced point of maximal impulse indicating LV hypertrophy.
    • Sustained and prolonged left parasternal heave indicating RV hypertrophy.

    Risk factors:

    • Family history.
    • Smoking.
    • Hypertension.
    • Diabetes.
    • Obesity.
    • History of alcohol or drug use.
    • Sedentary lifestyle.
    • Coronary artery disease.
    • Male gender.
    • Age > 65.
    • African-American.

    Diagnostic Process

    The diagnosis of cardiomegaly is based on imaging and suggested by ECG.

    If heart failure present:
    Visit The New York Heart Association based on symptoms:
    https://www.heart.org/en/health-topics/heart-failure/what-is-heart-failure/classes-of-heart-failure .


    • Chest X-ray.
      • Enlarged cardiac silhouette with a cardiothoracic ratio > 50%.
      • Heart failure:
        • Interstitial edema.
        • Pleural effusion.
        • Alveolar edema.
      • LV enlargement.
        • Leftward displacement of left heart border.
      • RV enlargement.
        • Upward deviation of the left apical margin.
      • LA enlargement.
        • Double density sign.
      • RA enlargement.
        • Increased convexity of the right heart border.
      • Transthoracic echocardiogram.
        • Assess size, function and possibly etiology.
      • Coronary angiography.
      • Cardiac computerized tomography (CT) scan.
      • Cardiac magnetic resonance imaging (MRI).
        • Emerging diagnostic modality for accurate evaluation of LV and RV mass, size and function. It can characterize ischemic and non-ischemic causes such as myocarditis.


    • Electrocardiogram (ECG).
      • Reveals non-specific changes including LV/RV hypertrophy, arrhythmias, fibrosis or cardiomyopathy.
      • See Acute Heart Failure for specific ECG findings.
    • Lab work:
      • CBC, electrolytes, urea, creatinine, liver function tests, TSH, glucose.
      • Cardiac enzyme serum levels (used in setting of heart failure).
        • Troponin.
          • Elevation = worse prognosis.
        • N-terminal pro-B-type natriuretic peptide (NT-proBNP).
          • Useful to monitor ongoing management and has prognostic value.
          • BNP <100 nanograms/L or NT-proBNP <300 nanograms/L strong negative predictors of heart failure.
          • BNP >400 nanograms/L or NT-proBNP >900 (>1800 if age 75+) nanograms/L make heart failure more likely.

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