What is a Heart Murmur?

What does it mean when someone says they have a heart murmur? When a doctor puts a stethoscope on your chest and listens, they are listening for the rhythmic thumping of your heart. When they hear something extra they call this a heart murmur.

The sounds your heart makes comes from four heart valves opening and closing. The most prominent sounds are coming from the Mitral and Aortic valves. These valves are on the left side of the heart and are under more pressure than the right-sided heart valves. The lub dub sound a doctor hears are mainly these two valves opening and closing.

If the doctor hears an additional sound or murmur, it usually means the Mitral and or Aortic valves aren't functioning properly. A couple of things could be going wrong. Either the valve leaks or it doesn't open properly and is tight, or stenotic.

Heart valves are thin tissue that open and close depending on changing pressures within the heart. For example: the Mitral valve separates the left atrium from the left ventricle. The left atrium collects newly oxygenated blood from the lungs. When the left atrium fills with blood, it will exceed the amount of blood in the left ventricle. As a result the pressure in the left atrium will exceed the pressure in the left ventricle. This pressure will open the one way Mitral valve and the blood will rush into the left ventricle. When the pressure in the left ventricle exceeds that of the left atrium, the Mitral valve will close and the left ventricle will squeeze the blood out the Aortic valve into the body. The Mitral valve will remain shut during the left ventricular squeeze. This cycle is repeated over and over and is your heart beat.

A murmur is normally heard when the valves aren't working properly. If the Mitral valve or Aortic valve leaks it will make a swooshing sound. If the leak is severe enough it will be audible with a stethoscope.

The same goes if the valves don't open to their full extent. The same amount of blood needs to pass through the valves with every beat. If the orifice the blood travels through is smaller than it should be, the blood will move through the tighter area faster than normal. Think of what happens when you put your thumb over the nozzle of a garden hose. The water squirts through faster and makes a lot of noise. The noise in the case of a heart is a heart murmur.

Some murmurs are caused from a heart valve being malformed. This is usually a congenital condition, in other words you're born with it.

The most common congenital heart valve disorder is the bicuspid Aortic valve. The normal Aortic valve has three distinct cusps. A bicuspid valve has only two distinct cusps. This abnormality can cause a tightening in the valve, which translates to a heart murmur. As a bit of trivia, Arnold Schwarzenegger has this condition. In fact he had open-heart surgery to correct it.

Sometimes heart murmurs can be caused from a hole in the heart. Muscular walls separate the left and right sides of the heart. If a wall has a hole in it allowing blood to pass through to the other side, this will usually be audible to a doctor. These murmurs are usually associated with young children and may seal up over time. If they don't, open-heart surgery may be required.

Most heart murmurs are harmless. Heart valves aren't perfect; in fact most people have minor valve leaks. They may not be severe enough to hear, but they can be seen with an Echocardiogram, or cardiac ultrasound. If you have a heart murmur ask your doctor if an Echocardiogram would be a good option to better assess the condition.