Characteristic Heart Sounds in Tetralogy of Fallot

Unoperated/Pre-Repair Patients

The American Heart Association notes that unoperated patients with Tetralogy of Fallot typically present with a loud precordial systolic ejection murmur from right ventricular outflow tract obstruction, which can be mistaken for a small VSD 1
The intensity of the systolic ejection murmur is inversely related to cyanosis severity, with more severe obstruction producing less flow across the RVOT, resulting in a softer murmur and more cyanosis 1
Patients with severe obstruction and abundant aorticopulmonary collaterals may present with loud continuous murmurs over the thorax 1
In "pink tetralogy" (mild pulmonary obstruction), the loud precordial murmur often leads to misdiagnosis as an isolated VSD 1

The American College of Cardiology recommends that post-repair patients be evaluated for a soft ejection systolic murmur from the RVOT, with an absent P2 component of the second heart sound being the most consistent finding 1
A soft ejection systolic murmur from the right ventricular outflow tract is the most common finding in post-repair patients 1
An absent P2 component of the second heart sound is characteristic and reflects pulmonary valve disruption or absence 1
A low-pitched, delayed diastolic murmur in the pulmonary area indicates pulmonary regurgitation, which is nearly universal after transannular patch repair 1, 2
A pansystolic murmur suggests a residual VSD or VSD patch leak 1, 2
A diastolic murmur of aortic regurgitation may be present, particularly with aortic root dilation 1, 2

The absence or presence of specific heart sounds provides critical hemodynamic information, with an absent P2 with diastolic murmur strongly suggesting significant pulmonary regurgitation leading to RV volume overload 1, 4
A loud systolic murmur with preserved P2 may indicate residual or recurrent RVOT obstruction requiring intervention 1, 3
New or worsening murmurs in previously stable patients warrant comprehensive echocardiographic reassessment 3

The severity of pulmonary regurgitation is often underestimated by auscultation compared to Doppler echocardiography, with absence of an audible diastolic murmur not excluding significant pulmonary regurgitation 4
A loud P2 is NOT expected in repaired TOF and should prompt evaluation for pulmonary hypertension from alternative causes 5