2025 – PAGE 133 – 134 – CARDIOLOGY
TOTAL ANOMALOUS PULMONARY VENOUS RETURN (TAPVR)
There are four variants (types are not important) of Total Anomalous Pulmonary Venous Return (TAPVR) in which the PULMONARY VEIN leads to an anomalous VENOUS location. This OXYGENATED blood subsequently returns to the RA. Therefore, the oxygenated blood never enters the systemic circulation. It is located on the RIGHT side. Since essentially all of the blood is going to the RIGHT side of the heart, there is significant PULMONARY CONGESTION on the CXR. This is NOT COMPATIBLE WITH LIFE UNLESS A PFO/ASD IS PRESENT OR CREATED to allow blood to flow to the LA, LV, and then Aorta. The CXR shows a heart that is classically described as a “Snowman” (some say it looks more like a balloon). TREATMENT is to create or reopen the PFO/ASD.
MNEMONIC: “This one is #5 on the list of CCHDs, so imagine your entire hand reaching inside the chest of a SNOWMAN and ripping open an ASD.”
HYPOPLASTIC LEFT HEART
In hypoplastic left heart, everything on the LEFT side of the heart is small: small left ventricle, small mitral valve, small aortic valve, and small aorta. Because of the limited pumping ability, this results in CHF and a Left to RIGHT shunt across a PATENT FORAMEN OVALE (PFO). Blood reaches the periphery via a PDA (from PA to Aorta, a Right to LEFT shunt). If the PDA is allowed to close, the patient’s CHF worsens dramatically.
TRICUSPID ATRESIA
In tricuspid atresia, there may be essentially NO functional RV since the tricuspid valve did not form. In babies with a sizeable VSD, there may still be a functional RV. Blood goes from the RA to the LA via a PFO (a R to L shunt). Pulmonary circulation must be maintained through a PDA (with blood shunting from the aorta/periphery to the pulmonary artery, L to R shunt). The EKG will show LVH with LAD (Left Axis Deviation). Cyanosis occurs early, usually within hours to days. Treat with PROSTAGLANDIN to maintain the PDA, or the baby will eventually die.
PULMONARY ATRESIA (AKA PULMONARY VALVE ATRESIA)
Pulmonary atresia is very similar to tricuspid atresia. Since the pulmonary valve did not form, RV blood cannot flow from the right ventricle to the lung. This results in tricuspid regurgitation (systolic murmur). There’s usually a right to left shunt, either through a VSD (RV to LV) or through a patent foramen ovale (PFO) being kept open from the high pressure in the right atrium (RA to LA). Cyanosis occurs early (minutes to hours), a systolic murmur may be heard and the EKG will show LVH. Both a PDA and a right to left shunt are needed, otherwise this is fatal. To get oxygen into the pulmonary circulation, treat with prostaglandin to maintain the PDA. Diagnose by echocardiogram.
PEARL: It is unlikely that you would be asked to differentiate between tricuspid and pulmonary atresia.
EBSTEIN’S ANOMALY
In Ebstein’s anomaly, malformed and displaced tricuspid valves are partly attached to the RV, causing tricuspid regurgitation (TR) and right heart enlargement with RV dysfunction. It is associated with maternal exposure to lithium. The presentation is variable, but TR is commonly severe. Ebstein’s anomaly is associated with ASD, and symptomatic neonates often present with cardiomegaly and cyanosis from right-to-left shunting.
PERSISTENT PULMONARY HYPERTENSION = PERSISTENCE OF FETAL CIRCULATION
In persistent pulmonary hypertension (AKA persistence of fetal circulation), underlying pulmonary disease causes higher pulmonary vascular resistance. This results in a PDA with shunting from the PA to the Aorta (Right to LEFT) and resultant cyanosis. Nitric oxide can be given in an effort to allow greater blood flow into the lungs and thus reduce pulmonary HTN. The PDA will send deoxygenated blood to the descending aorta, so look for lower O2 sats in the RIGHT LEG compared to the RIGHT ARM (which is getting oxygenated blood that made its way to the lungs and then LV and ascending aorta. There is NO MURMUR but a possible right, parasternal heave from RVH.
PEARLS:
- BLUE/CYANOTIC BABY + CLEAR/BLACK CXR: CXR is clear due to a lack of pulmonary blood flow. Give PGE immediately to maintain a PDA and a LEFT to RIGHT shunt from the AORTA to the PA.
- FETAL HEMOGLOBIN: Because of the oxygen affinity of fetal hemoglobin, desaturation occurs at a significantly lower pO2 than with adult hemoglobin. Thus, desaturations and cyanosis represent more severe hypoxia. So if a neonate has a CCHD and mild anemia with O2 sats in the high 80s, the baby may look okay, but this could mean impending doom.
- DEVELOPMENTAL DELAY: MOST children with congenital heart disease (CHD) have at least mild developmental delay and learning problems, but children with cyanotic CHD have more problems than children with acyanotic CHD.
- LEFT AXIS DEVIATION: The differential for LAD on EKG in the setting of CHD includes either AV Canal Defect or TRICUSPID atresia. In tricuspid atresia, this is due to increased blood flow via a Right to LEFT shunt at a PFO/ASD (possibly created as treatment) resulting in LVH/LAD.
| CHD | Murmur | Shunt | Notes |
| Truncus | Possible systolic | R → L | PA and Ao are joined. Connected to RV and LV |
| TGA/TOGA | NONE | R → L at ASD or VSD. | Cyanosis within hours. Single S2. Egg shaped. Pulm congestion from LV → PA |
| Tricuspid Atresia | Possible systolic. Possible PS sounding murmur | R → L at ASD
L → R at a VSD and PDA |
Blood goes from RA to LA to LV to RV to PA (with a possible PS murmur) to lungs. Blood also goes to lungs via the PDA (so Ao to PA). Blood then goes from the lungs to LA to LV to Aorta to the Periphery. Note there’s a lot of mixing of “red” and “blue” blood. |
| TOF | Pulmonary stenosis | R → L at VSD | Shunt at VSD, more as PS worsens. Single S2 because the P2 (PV component) is absent/inaudible. No increase in pulm vasculature on X-ray. |
| TAPVR | L → R at anomalous vein
R → L at ASD |
Snowman (to me, looks more like a balloon) |