Cardiac shunts or septal defects, which are holes in the heart, may cause abnormal heart murmurs. This is most common in infants and children. Their magnitude is determined by the location and size of the holes. When blood flows abnormally between the blood vessels due to holes in the heart, irregular heart murmurs can occur.
Atypical heart murmurs may occur as a result of rheumatic fever. Rheumatic fever is a severe illness that must be treated as soon as possible. While rheumatic fever is now uncommon, it can cause direct damage to the heart valves, resulting in irregular blood flow. This results in unusual heart murmurs.
Mitral valve prolapse in adults may cause irregular heart murmurs. This is when a part of the mitral valve balloons out and prevents the valve from closing properly. The backward flow of blood through the valve can cause irregular heart murmurs, which can be dangerous.
