The purpose of this study is to determine if children with heart disease where there is only one pumping chamber("ventricle") have proteins (biomarkers") in the blood that can be used to monitor the function of their heart.

We will investigate whether levels of blood proteins in children with well-functioning hearts with one ("single") ventricle are similar to levels of these blood proteins in children with two ventricles. For children with hearts with a single ventricle, we will examine blood proteins at various levels of heart function. To assess blood protein levels, we will collect small (6 mL) samples of blood. Heart function will be determined by existing clinical scoring systems. Enrolled patients will receive an echocardiogram, which is a dynamic ultrasound picture of the beating heart.

Inclusion Criteria:

• Children with a structurally normal heart and a patent ductus arteriosus.
• Children with single ventricle physiology.

Exclusion Criteria:

• Children must not have chromosomal abnormalities. Small deletions, such as that which produces DiGeorge syndrome, are permissible.
• Children with acute intercurrent non-cardiac inflammatory illness (such as post-operative wound infection) are ineligible, as such conditions may cause elevated blood levels of the proteins under study.

Patients presenting to the UCSF Pediatric Heart Center.