I was found to have a cardiac bruit. what is this exactly and what are the causes?

Bruit: A bruit is a turbulent flow sound heard with the stethoscope. Turbulent flow happens across a valve in your heart. Either a valve does not close tightly during systolic ejection of blood. Or a valve does not open completely during ejection of blood. During systole the aortic and pulmonic valves should open wide and the mitral and tricuspid valves should close, to prevent "backflow ".

Misunderstanding: A cardiac murmur is a noise that can be detected when the examiner listens with his/her ears - usually through a stethoscope. It's caused by turbulence of blood flow through a valve or a chamber. When a murmur is detected outside the heart, it's called a "bruit". Thus, there is no such thing as a "cardiac bruit". Some bruits are quite normal - for instance, they're often found in pregnancy.

Bruit: A bruit is analogous to a murmur, it is caused by turbulent blood flow.