Mechanism of continuous murmur

1.High pressure system communicating with low pressure system
Intracardiac

• RSOV to RV, RA ,Pulmonary artery.
• Coronary artery fistula to cardiac chamber.

Extracardiac

• PDA.
• Aorto pulmonary septal defect.
• Pulmonary AVF.
• Systemic AVF.
• Anomalous left coronary artery from pulmonary artery.

2.Narrowing of vessel

• Coarctation of aorta.
• Peripheral pulmonary artery stenosis.
• Carotid stenosis.

3.Increased blood flow through vessels

• Venous hum - Devil’s murmur - root of neck.
• Venous hum (Cruveilhier – Baumgarten murmur) - umbilicus - in portal hypertension.
• Intercostal arteries - Coarctation of aorta.
• Bronchopulmonary anastomoses.
• Pulmonary atresia and TOF.
• Internal mammary artery - Mammary Souffle in pregnancy.