Continous Murmer is seen in all except
The continuous murmur is the murmur that begins in systole and continues without interruption, encompassing the second sound, throughout diastole or part of diastole.
Please note in the above definition of continuous murmur, They start in systole and not interpreted by second heart sound and goes into diastole for variable length.
In Lesions producing continuous murmurs, the direction of flow of blood does not change from systole to diastole.
In the case of Aortic stenosis with aortic regurgitation, there are two murmurs produced by the flow of blood in the opposite direction. i.e aortic stenosis produces Ejection systolic murmur (mid systolic murmur) direction of flow of blood is from left ventricle to aorta and in aortic regurgitation, we get an early diastolic murmur, the murmur is produced by the backflow of blood from the aorta to left ventricle such murmurs are called to-and-fro murmurs.
Causes of a continuous murmur
1. Patent ductus arteriosus.
2. Aortopulmonary window.
3. Ruptured sinus of Valsalva aneurysm.
4. Anomalous origin of a left coronary artery from the pulmonary artery.
5. Accessory coronary artery.
6. Coronary-arterial fistula.
7. Coronary artery stenosis.
8. Systemic arteriovenous fistula.
9. Venous Hum