Cardiomegaly
Michael D. Puchalski, MD
DIFFERENTIAL DIAGNOSIS
Common
Cardiac
Ebstein Anomaly
Tricuspid Dysplasia
Dilated Cardiomyopathy
Unbalanced Atrioventricular Septal Defect
Tetralogy of Fallot with Absent Pulmonary Valve
Non-Cardiac
Twin Related Heart Failure
Twin-Twin Transfusion Syndrome
Twin Reversed Arterial Perfusion
Vascular Shunting
Sacrococcygeal Teratoma
Chorioangioma
Vein of Galen Malformation
ESSENTIAL INFORMATION
Key Differential Diagnosis Issues
Cardiomegaly defined as heart circumference > 50% of chest circumference or cardiac area > 33% of chest area
Is it a singleton pregnancy or multiple gestation?
Twin-twin transfusion syndrome (TTTS) and twin reversed arterial perfusion (TRAP) sequence only occur in monochorionic twin pregnancies
TTTS: Two normal looking fetuses with asymmetric size, fluid distribution
TRAP: One normal, one very anomalous fetus
Twin demise in monochorionic pregnancy may result in ischemic cardiomyopathy in the survivor
Follow carefully after twin demise; may take 10-14 days to see full extent of damage
Any other of the causes can occur in a singleton or in one of a dichorionic pair
Is the fetus structurally normal?
Look for masses/arteriovenous malformation
Is the intracardiac anatomy normal?
Is the function normal?
Are there one or two atrioventricular valves in the heart?
Is there tricuspid regurgitation (TR)?
Are the leaflets normally located?
Are the leaflets thickened/dysplastic?
Helpful Clues for Common Diagnoses
Ebstein Anomaly
Apical displacement of septal and posterior mural tricuspid valve leaflets with attachment to the ventricular septum
“Atrialization” of the right ventricle → right atrial enlargement
Anterior leaflet is often “sail-like”
TR may be severe
Pulmonary artery often small due to lack of antegrade flow in setting of severe TR
Tricuspid Dysplasia
Thick, nodular, or irregular valve leaflets in normal position
Severe TR results in right atrial dilation
Often associated pulmonary stenosis/atresia
Dilated Cardiomyopathy
No structural abnormality is present
Poor myocardial contractility
Myocardium often thin
Atrioventricular regurgitation
Unbalanced Atrioventricular Septal Defect
Missing “crux” of heart in four chamber view
Inlet ventricular septal defect
Primum atrial septal defect
Single AV valve is committed more to one ventricle
Ventricle lacking commitment will be hypoplastic
Look for features of heterotaxy syndromes, especially anomalous venous drainage
Tetralogy of Fallot with Absent Pulmonary Valve
Dilated aorta overriding a ventricular septal defect
Back and forth flow across pulmonary valve seen with color Doppler
Markedly enlarged main and branch pulmonary arteries
Twin-Twin Transfusion Syndrome
Recipient twin is the one at risk for developing cardiomegaly
Monochorionic twins with asymmetric fluid distribution and growth
Donor shunts blood to recipient circulation → volume overload
Recipient: Polyhydramnios, larger size, ± abnormal Doppler, ± hydrops
Donor: Oligohydramnios, smaller size, ± absent bladder, ± abnormal Doppler
Increased flow to the recipient twin causes high output failure
Biventricular hypertrophy
Tricuspid and mitral regurgitation
Abnormal ductus venosus flow
Twin Reversed Arterial Perfusion
Pump twin is the one at risk for developing cardiomegaly
Monochorionic twins
One normal “pump twin”
One anomalous “acardiac” twin
Flow in “acardiac” umbilical artery is toward fetus
Often lacks cranium/upper extremities
May have rudimentary or absent heart
Grossly edematous
Normal twin develops cardiomegaly and failure from perfusing the abnormal twin, which can reach enormous size
Sacrococcygeal Teratoma
Exophytic, mixed cystic/solid mass extending from sacrum
May contain calcifications
Polyhydramnios, placentomegaly
Solid tumors may have significant arteriovenous shunting
High output state → cardiomegaly → hydrops
Hydrops is very poor prognostic sign
Chorioangioma
Well-defined hypoechoic placental mass, most often near cord insertion
Variable vascularity
Large, highly vascular ones more likely to cause cardiomegaly and hydrops
Fetal anemia may occur secondary to hemolysis
Monitor with middle cerebral artery peak systolic velocity
Vein of Galen Malformation
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