What type of murmur is associated with Patent Ductus Arteriosus (PDA)?

From the Guidelines

A continuous "machinery-type" murmur heard best at the left infraclavicular area is typically associated with Patent Ductus Arteriosus (PDA). This type of murmur is almost diagnostic of a moderate or large PDA, as stated in the acc/aha 2008 guidelines for the management of adults with congenital heart disease 1. The characteristics of this murmur are due to the continuous flow of blood from the higher-pressure aorta to the lower-pressure pulmonary artery throughout the cardiac cycle.

Key Characteristics of the Murmur

• The murmur is usually loudest during late systole and early diastole
• It has a crescendo-decrescendo quality
• The intensity and characteristics of the murmur can vary depending on the size of the PDA and the pressure gradient across it
• In cases where pulmonary hypertension develops, the diastolic component may diminish or disappear entirely, potentially converting to a solely systolic murmur in severe cases, as noted in the guidelines 1.

Clinical Considerations

• A wide pulse pressure is present when the PDA is large and there is a large left-to-right shunt
• The oxygen saturation in the upper and lower extremities may be helpful in diagnosis of a large PDA with right-to-left shunt at the ductal level, as described in the guidelines 1
• Other causes of wide pulse pressure, such as aortic insufficiency and hyperthyroidism, must be distinguished from PDA.

From the Research

Type of Murmur Associated with Patent Ductus Arteriosus (PDA)

• The type of murmur associated with PDA is a machinery murmur 2.
• This murmur is typically continuous, meaning it occurs throughout both systole and diastole, and is often described as having a "machinery" or "freight train" quality 3.
• The presence of a machinery murmur is a common clinical sign of PDA, and is often accompanied by other symptoms such as tachycardia, increased respiratory rate, weakness, and ill thrift 2.

Characteristics of the Murmur

• The murmur associated with PDA is usually loudest at the left upper sternal border 3.
• It can be heard in both systole and diastole, and may radiate to the back or to the apex of the heart 2.
• The murmur may disappear or become softer after successful treatment of the PDA, such as with surgical ligation or pharmacological closure 3.

Diagnosis and Treatment

• The diagnosis of PDA is typically made using echocardiography, which can visualize the patent ductus and assess blood flow through it 4, 5, 6.
• Treatment options for PDA include pharmacological closure with medications such as indomethacin or ibuprofen, or surgical ligation 4, 5, 6, 3.
• The choice of treatment depends on the individual patient's condition, including the size of the PDA, the presence of symptoms, and the patient's overall health status 4, 5, 6, 3.