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.

Etiologies

• 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

 History

• 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.

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 .

Imaging

• 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.

Investigations

• 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.

1.  Cardiomegaly.
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2. Heart failure: clinical manifestations and diagnostic in adults.
   Colucci, W. S., Borlaug, B.A. (2021). [cited 2021 Apr 26].
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3. Effect of heart-size parameters computed from digital chest radiographs on detection of cardiomegaly. Potential usefulness for computer-aided diagnosis.
    Nakamori, N., MacMahon, H., Sasaki, Y., & Montner, S. (1991). Investigative radiology, 26(6), 546-550.
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