Continuous murmur is present in

A continuous murmur is predicated on a pressure gradient that persists between two cardiac chambers or blood vessels across systole and diastole.The murmurs typically begin in systole, envelop the second heart sound (S 2 ), and continue through some portion of diastole. They can often be difficult to distinguish from individual systolic and diastolic murmurs in patients with mixed valvular heart disease.  The classic example of a continuous murmur is that associated with a patent ductus arteriosus, which usually is heard in the second or third interspace at a slight distance from the sternal border. Other causes of a continuous murmur include a ruptured sinus of Valsalva aneurysm with creation of an aortic–right atrial or right ventricular fistula, a coronary or great vessel arteriovenous fistula, and an arteriovenous fistula constructed to provide dialysis access.