Differential diagnosis of continuous thoracic murmurs (in order of frequency)

Diagnosis	Key findings
Cervical venous hum	Disappears on compression of the jugular vein
Hepatic venous hum	Often disappears with epigastric pressure
Mammary souffle	Disappears upon pressing hard with stethoscope
Patent ductus arteriosus	Loudest at 2nd left intercostal space
Coronary arteriovenous fistula	Loudest at lower sternal borders
Ruptured aneurysm of sinus of Valsalva	Loudest at upper right sternal border, sudden onset
Bronchial collaterals	Associated signs of congenital heart disease
High-grade coarctation	Brachial-pedal arterial pressure gradient
Anomalous left coronary artery arising from pulmonary artery	Electrocardiographic changes of myocardial infarction
Truncus arteriosus
Pulmonary artery branch stenosis	Heard outside the area of cardiac dullness
Pulmonary AV fistula	Same as above
Atrial septal defect with mitral stenosis or atresia	Altered by the Valsalva maneuver
Aortic-atrial fistulas

Graphic 50660 Version 11.0