Patent Ductus Arteriosus

Patent Ductus Arteriosus


-Embryonic ductus arteriosus allows shunting of blood from the PA to the aorta, bypassing the lungs 

-It normally closes immediately after birth 

-Failure to close results in left-to-right shunt 

-Risk factors: Down syndrome, rubella, 

Symptoms & signs 

-Usually asymptomatic at birth and during childhood 

-No symptoms in mild cases 

-Shortness of breath, sweating, almost always acyanotic but differential cyanosis can happen; lower extremities and sometimes the left hand show clubbing and cyanosis, but the right hand and head are always pink

-Continuous ‘machinery’  ‘to-and-fro’ murmur loudest over left pulmonary area below the left clavicle, widened pulse pressure, loud S2, accentuated in late systole at the time of S2, S2 is obliterated by the waxing and waning of the murmur 

Complications: Left heart dilation, pulmonary hypertension, Eisenmenger syndrome, heart failure, infective endocarditis 


Chest X-ray: normal 

ECG: normal or left atrial and ventricular hypertrophy 

Echocardiogram: left atrial and ventricular enlargement 


-Prior to birth, circulating prostaglandins keep the ductus patent, so a PDA can be closed by administering a prostaglandin inhibitor like indomethacin 

 Indomethacin is ineffective in term infants with PDA 

-Surgical ligation 

Tetralogy of Fallot

Tetralogy of Fallot 


-Tetralogy of Fallot (TOF) is the most common form of cyanotic Congenital heart disease

-it is associated with trisomy 21 

–it has 4 anatomic components:

1.ventricular septal defect

2.right ventricular hypertrophy

3.pulmonary stenosis

4.overriding aorta 

-It results in not enough blood going to the lungs to get oxygen, and the oxygen-poor blood is pumped to the rest of the body

Symptoms & Signs 

-Clinical presentation depends on the degree of RV outflow obstruction 

-Most present by 6 months of age; -right to left shunt causes cyanosis, hypoxemia (blue illness); Baby ‘turning blue’ with feeding or crying, failure to thrive

‘Tet spells’: cyanotic episodes with deep breathing, irritability, prolonged crying, child squats to interrupt the spells 

-Harsh crescendo-decrescendo systolic ejection murmur best heard at the left upper sternal border (due to RVOT obstruction), single second heart sound 

-Most common residual defect after TOF surgery: pulmonary regurgitation 


ECG: The ECG reveals RVH and right axis deviation; in repaired tetralogy, there is often a right bundle branch block pattern.

Chest X-ray: Boot-shaped heart (coeur en sabot sign) 

Echocardiogram: Delineates TOF and quantifies degree of RV outflow obstruction 

Cardiac MRI and CT can quantitate both the pulmonary regurgitation and the RV volumes. 


-Surgical repair is the definitive treatment of choice 

-most adult patients have had surgical repair, 

-The goal of surgical repair is to alleviate the pulmonary stenosis and close the VSD