Pathologic Heart Murmurs
A murmur is an extra heart sound that is detected by using a stethoscope. Most murmurs are produced by turbulent blood flow. A murmur can be detected at a certain time in over 90 percent of children. Less than 10 percent of these murmurs are pathologic (abnormal). The vast majority are innocent heart murmurs.
Unlike an innocent heart murmur, a pathologic murmur is produced by blood flowing through a narrowed blood vessel or hole in the heart. It may also be produced when blood flows through an obstructed or leaky heart valve. The quality of this type of murmur is not musical or vibratory. It is usually blowing, squeaky, or a whooshing sound. A pathologic murmur has certain characteristics that may distinguish it from an innocent heart murmur. The pathologic murmur may sound harsher and may last longer. It may also be louder. The timing and duration of the murmur during the cardiac cycle may help differentiate a pathologic from an innocent heart murmur.
In addition, pathologic murmurs may be accompanied by a clicking sound or an extra heart sound. The pathologic murmur may also be heard in more than one specific area of the chest or back. In other words, the murmur may transmit to other areas of the chest.
There are times that even an experienced physician may have difficulty distinguishing between different types of heart murmurs. In addition, there are several conditions where the murmur may not correlate with the severity of the heart defect. In those cases, an echocardiogram is very helpful.