Heart murmur is a sound that is relatively common found during examination of a patient by listening to the heart (listening by ear, or using a stethoscope). It is good to remember that not every murmur in the chest must be connected right to the heart, but other sources are much less common. A randomly found murmur is usually not a serious symptom, but it should be more precisely examined including the use of imaging methods.
Heart murmur is most commonly associated with the disorder of one or more of the four heart valves. There are simply told two main types of valve disorders – valvular stenosis and valvular insufficiency. Stenosis means that the valve does not open fully and resists the blood flow, insufficient valves do not close properly and allow blood backflow. Volume murmur usually corresponds to the severity of the defect, but it is not always the rule. Very experienced cardiologist would be theoretically able to determine the exact type of disorder only by listening, but modern determination is done by echocardiography that accurately describes the type of defect and its severity. Severe valvular disorders usually manifest with symptoms of heart failure (fatigue, fainting, shortness of breath, legs swelling etc.). Small and insignificant valvular disorders can be just monitored; serious cases are solved by cardiac surgery procedures with implantation of artificial heart valves (see the relevant article about valvular heart disease).
Pericarditis is an inflammation of the pericardium that is which is a sac surrounding the heart. It has a number of causative agents and its manifestation can mimic acute heart attack (including some ECG changes). When using stethoscope, a friction rub can be heard as the inflamed pericardium rubs against the heart muscle tissue. After some time pericardium irritation is followed by fluid production that accumulates in pericardial sac. A great amount of fluid can theoretically compress the heart and prevent it from pumping (the so-called cardiac tamponade).
This is a dangerous condition where blood clot colonized by bacteria occurs inside heart cavities, typically on a heart valve. These so-called “bacterial vegetations” can damage heart valves and they can also become a source of infection spreading throughout the body by infected blood (sepsis). Bacterial vegetation can become a barrier to the blood flow and may therefore entail a murmur. In addition symptoms of infection are present (fever, fatigue, malaise, night sweats) and sometimes even signs of heart failure and arrhythmias occur.
Congenital heart defects
Heart defects associated with abnormal flow of blood through the heart are accompanied with murmur occurrence. The murmur is present from birth and it is usually discovered during regular pediatric examination. In more serious defects murmur presence is followed by signs of heart failure and impaired blood oxygenation.
Heart tumors are quite rare. Heart tumor can become an obstacle for blood flow as it grows into the heart cavities. In such case a heart murmur emerges.
Pleurisy is, of course, not a heart murmur, but it can cause similar sound. Pleurisy is inflammation of pleura lining chest cavity. A friction rub occurs accompanied with a murmur that is audible on the back side of the chest and typically during inspiration. Chest pain is another usual symptom.
Murmurs are usually diagnosed with a stethoscope, severe forms of murmurs may be audible even simple by ear. According to the exact listening position and sound transmission of a valvular murmur, skilled doctor can evaluate which valve is affected and what is the nature of its disorder. Echocardiography is a necessary examination, because it reveals information about heart anatomy and function including the heart valves. It has even high chance to diagnose presence of infective endocarditis, but more successful in this regard is transesophageal echocardiogram. To rule out other pathologies is it appropriate to do chest X-ray to check lungs and pleura.