Cyanosis in Atrial septal defect
Cyanosis in atrial septal defect
Cyanosis in atrial septal defect
Cyanosis in atrial septal defect may result from all of the following except
[A] Eisenmenger syndrome
[B] Prominent eustachian valve
[C] Sinus venosus ASD
[D] Associated complex congenital heart disease
Cyanosis in Atrial septal defect
Causes of cyanosis in ASD
- Eisenmenger syndrome
- Prominent eustachian valve – direct IVC flow to the left atrium via a secundum ASD or sinus venosus ASD of the inferior vena caval type
- Large ASD with equalisation of LA & RA pressures
- ASD with associated valvar pulmonic stenosis
- IVC blood can stream into LA by hitting preferentially the lower part of IAS (inter atrial septum), thus producing right-to-left shunt & cyanosis.
- During straining, (Valsalva and equivalents) right atrial pressure can exceed LA pressure & can cause cyanosis.
- In ASD with systemic venous anomaly like persistent left SVC connected to coronary sinus and with that coronary sinus connected to the LA, there can be significant cyanosis
Cyanosis in Atrial septal defect
Elevated right atrial pressure & abnormalities of right ventricular filling
The flow across a large, nonrestrictive ASD is determined by the flow across tricuspid valve which in turn depends upon the compliance of the right ventricle.
- Left to right shunt across ASD is impaired in cases with RA myxoma due to mechanical obstruction to the tricuspid valve inflow.
- Reduced RV systolic function – RV myocardial infarction, RV cardiomyopathy and diastolic dysfunction in patients with pulmonary stenosis poses functional obstruction to the tricuspid valve inflow and in turn impairs flow across ASD.
- This impairment is severe flow across an ASD reverses resulting in cyanosis
Gerbode defect
Gerbode defect is defined as abnormal shunting between the left ventricle and right atrium resulting from either a congenital defect or prior cardiac insults
