A heart murmur is a sound heard during a physical examination that is distinct from the normal “lub-dub” of the heart. This extra sound, often described as a whooshing or swishing noise, is caused by turbulent blood flow within the heart or major blood vessels. Murmurs are common and do not automatically signal a serious problem, as many are harmless and represent blood flowing through a healthy heart at a faster-than-usual rate. However, a murmur can also indicate an underlying structural heart issue, such as a problem with a heart valve or a congenital defect. Determining the cause of the turbulent flow dictates the course of action, which can range from no treatment to complex surgical intervention.
Differentiating Murmurs: Innocent Versus Pathological
The initial step in managing a heart murmur is to determine its type, as this dictates the entire treatment strategy. Murmurs fall into two broad categories: innocent and pathological. Innocent murmurs, also called physiological or functional murmurs, are sounds produced by a normal heart where no structural abnormality exists. These often occur when blood flow is temporarily increased, such as during a fever, pregnancy, or periods of rapid growth.
Pathological murmurs signal an underlying structural problem within the heart or blood vessels, which could be congenital or acquired. These murmurs are typically caused by issues like a stiffened or narrowed heart valve (stenosis), a leaky valve allowing blood to flow backward (regurgitation), or a hole in the heart’s wall (septal defect). Diagnosis begins with a physician listening with a stethoscope, analyzing the sound’s intensity, pitch, timing, and location.
If a pathological murmur is suspected based on the physical exam, further testing confirms the diagnosis and identifies the exact cause. An echocardiogram, which uses ultrasound to create moving images of the heart, is the most common test used to visualize the heart’s structure and blood flow dynamics. An electrocardiogram (EKG) may also measure the heart’s electrical activity, looking for signs of strain or enlargement associated with a structural defect.
Management and Monitoring of Innocent Murmurs
When a heart murmur is confirmed to be innocent, the management approach focuses on reassurance. These murmurs do not represent a disease, are harmless, and do not compromise the heart’s function. They are a normal physical finding that can be present in up to 75% of children.
No medical intervention, medication, or surgery is necessary for an innocent murmur. Patients are encouraged to maintain a normal, active lifestyle without restrictions on diet or physical activity. The physician documents the finding to prevent unnecessary worry or workup in future examinations. Follow-up is usually limited to routine checkups, as the murmur may lessen or disappear entirely as the patient ages.
Active Medical Treatment for Pathological Murmurs
When a murmur is determined to be pathological, medical treatment focuses on managing the underlying heart condition, alleviating symptoms, and preventing complications. These treatments do not correct the structural issue itself, but instead reduce the strain on the heart caused by the defect. For example, if a leaky valve has led to heart failure symptoms, diuretics may be prescribed to reduce excess fluid and salt retention in the body. This makes it easier for the heart to pump blood effectively, relieving congestion.
Medications that lower blood pressure, such as Angiotensin-Converting Enzyme (ACE) inhibitors or beta-blockers, are often employed to reduce the workload on the heart. ACE inhibitors help by relaxing blood vessels, which lowers the resistance against which the heart must pump. Beta-blockers work by slowing the heart rate and decreasing blood pressure, which lessens the force of each contraction and can help manage symptoms like palpitations.
Anticoagulant medications, or blood thinners, may be necessary if the structural problem increases the risk of blood clot formation, particularly with certain valve diseases. Preventing clots is important to reduce the risk of serious events like stroke. In high-risk patients, such as those with a history of infective endocarditis or prosthetic heart valves, prophylactic antibiotics may be recommended before certain dental or surgical procedures to prevent infection of the heart lining.
Interventional and Surgical Repair Options
For severe pathological murmurs, a procedure is often necessary to correct the underlying problem. These interventions aim to repair or replace damaged heart valves or close abnormal openings in the heart’s walls. Open-heart surgery remains a definitive option, allowing surgeons to directly repair a valve by patching holes, separating fused leaflets, or reinforcing the surrounding ring.
When repair is not feasible, the entire valve may be replaced with either a bioprosthetic valve, made from animal tissue, or a mechanical valve. Mechanical valves are highly durable but require the patient to take lifelong anticoagulant medication due to the high risk of clotting. Tissue valves generally do not require long-term anticoagulation, but they typically wear out after 10 to 20 years and may need eventual replacement.
Catheter-based procedures have become a preferred option for some structural defects, particularly those involving heart valves. For example, balloon valvuloplasty can widen a narrowed valve by inserting a catheter with a balloon tip that is inflated at the site of the blockage. Transcatheter procedures, such as Transcatheter Aortic Valve Replacement (TAVR) or the placement of an umbrella-like closure device for an Atrial Septal Defect (ASD), allow for repair via small incisions in the groin or chest, reducing recovery time.