CCHD with low pulmonary blood flow and cardiomegaly

CCHD with low pulmonary blood flow and cardiomegaly

What are the situations of CCHD and low pulmonary blood flow with cardiomegaly on chest X-ray?

1. Tetralogy of Fallot with aortic regurgitation
2. TOF with large collaterals
3. Ebstein’s anomaly of tricuspid valve – cardiomegaly due to right atrial enlargement
4. TOF with anemia and heart failure
5. TOF with AV canal defects

It may be noted that simple tetralogy of Fallot has a normal sized heart on chest X-ray. This is because none of the cardiac chambers are grossly dilated, though right ventricle is hypertrophied. TOF with AR causes cardiomegaly due to left ventricular enlargement when the aortic regurgitation is severe. Aortic regurgitation can progress even after repair of TOF. In one series of 427 patients who underwent TOF repair, four needed aortic valve procedure late after TOF repair [1].

Large aortopulmonary collaterals also increase the load on the left ventricle causing enlargement. In TOF with AV canal defects cardiomegaly is a sequel of atrioventricular valve regurgitations. Significant mitral regurgitation causes left atrial and left ventricular dilatation while significant tricuspid regurgitation causes right atrial and right ventricular dilatation.

Reference

1. Ishizaka T, Ichikawa H, Sawa Y, Fukushima N, Kagisaki K, Kondo H, Kogaki S, Matsuda H. Prevalence and optimal management strategy for aortic regurgitation in tetralogy of Fallot. Eur J Cardiothorac Surg. 2004 Dec;26(6):1080-6.