So you have a murmur and the doctor told you it is benign. That means that after ECHO cardiogram the doctor did not find any serious problem with your valves or holes in the walls of the heart. So don t worry about it now. The opposite of Benign is not malignant in case of heart murmurs. If it is not benign we can call it pathological. That means there is some definite reason for the murmur like a valve problem or a septal defect. All murmurs are not serious. So if your doctor told you it is fine, don t worry about it at present. In future if you get any palpitation or shortness of breath you can have a re assessment with your cardiologist. It is unlikely that the present benign problem will progress to a serious one later.