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cardiomegaly
Enlargement of the heart.
Etiology:
1) cardiac chamber enlargement
a) left ventricle
- chronic volume overload
- mitral regurgitation
- aortic regurgitation
- left to right shunt
- patent ductus arteriosis
- ventricular septal defect
- AV fistula
- cardiomyopathy (congestive heart failure)
- ischemic
- nonischemic
- decompensated pressure overload
- aortic stenosis
- hypertension
- high output states
- severe anemia
- thyrotoxicosis
- bradycardia
- severe sinus bradycardia
- complete heart block
b) left atrium
- left ventricular failure
- mitral valve disease
- atrial myxoma
c) right ventricle
- chronic left ventricular failure
- chronic volume overload
- tricuspid regurgitation
- pulmonic regurgitation
- left to right shunt (atrial septal defect)
- decompenstated pressure overload
- pulmonic stenosis
- pulmonary artery hypertension
- primary
- secondary: pulmonary embolism, chronic obstructive pulmonary disease
d) right atrium
- right ventricular failure of any cause
- tricuspid valve disease
- atrial myxoma
- Ebstein's anomaly
e) multichamber enlargement
- hypertrophic cardiomyopathy
- acromegaly
- severe obesity
- glycogen storage disease, type II (infants, children)
2) pericardial disease
a) pericardial effusion -> with or without pericardial tamponade
b) effusive constrictive pericarditis
c) pericardial cyst or loculated effusion
3) pseudocardiomegaly
a) epicardial fat
b) chest wall deformity
- pectus excavatum
- straight back syndrome
c) low lung volumes
d) AP chest X-ray (vs PA)
e) mediastinal tumor or cyst
Clinical manifestations:
1) point of maximum impulse may be > 10 cm from mid-sternal line or lateral to the mid-clavicular line
2) point of maximum impulse may be > 3 cm in diameter
3) point of maximum impulse may be lower than 5th intercostal space
Laboratory:
1) complete blood count
2) chem 7
3) liver function tests
4) thyroid function test
5) lipid panel
6) atrial natriuretic peptide (ANP)
Special laboratory:
1) electrocardiogram
2) exercise stress testing or myocardial perfusion study to assess coronary artery disease
Radiology:
1) chest X-ray (also see heart)
a) cardiomegaly may be incidental finding
b) a cardiothoracic ratio of >= 0.5 on PA film (widest transverse dimension of cardiac silhouette)
2) echocardiography
3) radionuclide ventriculography
4) computed tomography provides better indication of pericardial thickness than echocardiography
5) coronary angiography (as late step in the evaluation of coronary artery disease)
Management:
- treat specific etiology
General
heart disease (cardiac disease)
sign/symptom
References
- nlmpubs.nlm.nih.gov/hstat/ahcpr/
- Stedman's Medical Dictionary 27th ed, Williams &
Wilkins, Baltimore, 1999
- O'Gara, PT, Cardiac Enlargement, in: Primary Cardiology,
Goldman L & Braunwald E (eds), WB Saunders, Philadelphia,
1998, pg 174