Fallot like physiology – cyanotic heart disease with low pulmonary blood flow
Tetralogy of Fallot
D- Transposition of great vessels (TGA) with ventricular septal defect (VSD) and pulmonary stenosis (PS)
L- TGA with VSD and PS
Tricuspid atresia with VSD and PS
Double outlet right ventricle (DORV) with VSD and PS
Single ventricle with PS
Beyond the age of 4 years, 90% of Fallot like physiology will be due to Tetralogy of Fallot
TGA like physiology – cyanotic heart disease with high pulmonary blood flow
D- TGA with VSD and no PS
DORV with VSD and no PS
Tricuspid atresia with VSD and no PS
Admixture lesions – near equal saturations in aorta and pulmonary artery
Total anomalous pulmonary venous connection (TAPVC)
Total anomalous systemic venous connection (TASVC)
Single atrium
Single ventricle
Truncus arteriosus
Univentricular Heart
One dominant ventricle and a rudimentary ventricle, usually just an outflow chamber. Dominant ventricle has a double inlet.
Venesection in cyanotic heart disease – calculation of volume to be removed
Done only in symptomatic polycythemia with hemoglobin > 20 gm% and hematocrit > 65 %
Has to be replaced with equal amount of saline.
Volume of blood to be removed by venesection in ml:
[(Observed PCV – Desired PCV ) / Observed PCV] x 70 x body weight in Kg.
Desired PCV is calculated based on the oxygen saturation. Average desired PCV is about 60 for a cyanotic person.
Long systolic murmur with severe cyanosis in Tetralogy of Fallot (TOF)
Usually the murmur (originating from RVOT) in TOF is short if there is severe cyanosis as the flow across RVOT is less (blood gets preferentially shunted across the VSD into the aorta).
A long murmur can occur in:
TOF with absent pulmonary valve
Restrictive VSD – long murmur due to tricuspid regurgitation, as the right ventricular pressure may go supra-systemic
AV canal defect – long murmur due to AV valve regurgitation