If when you write "belly sounds" you mean a "growling" noise arising from the abdomen, you are hearing a normal sound arising from normal contractions of the intestines and the movement of air and fluid within them. One has to be concerned about a problem in the digestive tract if on listening with a stethoscope over the abdomen the physician hears no sounds after listening steadily for several minutes. The only heart problems I can think of which might affect the abdominal sounds a doctor hears with the stethoscope would be a blood clot coming from the heart and blocking arteries supplying blood to the intestines. This would be a rare event and the patient would be aware of other symptoms related to the heart and without a stethoscope might not hear anything abnormal. For more regarding "belly sounds" go to the following website for an article by Robert H. Shmerling, M.D. of Beth Israel Deaconess Medical Center:
http://www.intelihealth.com/IH/ihtIH/WSIHW000/35320/35323/405945.html?d=dmtHMSContent

I hope my answer helps to answer your question. ..Maurice.