Long systolic murmur with severe cyanosis in Tetralogy of Fallot (TOF)

Long systolic murmur with severe cyanosis in Tetralogy of Fallot (TOF)

Usually the murmur originating from right ventricular outflow tract in tetralogy of Fallot is short if there is severe cyanosis as the flow across RVOT is less as the blood gets preferentially shunted across the ventricular septal defect into the aorta.

Long systolic murmur with severe cyanosis in Tetralogy of Fallot can occur with:

1. TOF with absent pulmonary valve
2. Restrictive VSD – long murmur due to tricuspid regurgitation, as the right ventricular pressure may go supra-systemic
3. AV canal defect – long murmur due to AV valve regurgitation