What exams, tests, and imaging studies diagnose heart murmurs in infants, children, and adults?
A heart murmur is usually diagnosed during a physical examination by the health care practitioner while he or she listens to heart sounds with a stethoscope.
Evaluation of the heart begins with questions relating to heart function. In an adult, some questions may include asking about chest pain or pressure, shortness of breath with exertion or at rest, and swelling of the legs. In an infant, the symptoms may include poor sucking or eating, poor weight gain and growth, or episodes of cyanosis (turning blue).
Physical examination includes assessing skin color, feeling and assessing pulses, evaluating the legs looking for swelling and edema, and listening to the lungs for signs of fluid buildup.
Heart evaluation includes assessing the rate and rhythm of the heart. Is it too fast, too slow, regular, or irregular? The front of the chest can be palpated; a hand is placed on the area overlying the heart trying to feel for a vibration (thrill) that can occur with an especially significant heart murmur.
Listening to the heart with the stethoscope begins with assessing basic first and second heart sounds, S1 and S2, which sound like "lub-dub." Potential extra heart sounds are referred to as S3 and S4. Should a heart murmur be heard, the health care practitioner will try to determine whether the sound is coming from an abnormal valve or a defect in the atrial or ventricular septum. The murmur is described whether it is heard in systole (when the heart is pumping) or diastole (when the heart is filling). The location on the chest and where the sound radiates is important in determining where the murmur originates. The intensity of the murmur is usually graded on a 6 point scale are:
- 1/6 faintly heard
- 2/6 easily heard but soft
- 3/6 easily heard but loud
Murmurs graded 4, 5, and 6 have an associated vibration (thrill) felt when the chest wall is palpated:
- 4/6 loud murmur
- 5/6 loud murmur that can be heard with only part of the stethoscope touching the chest
- 6/6 loud murmur that can be heard with the stethoscope off the chest
Many murmurs are diagnosed as normal (physiologic) based upon physical examination and require no further evaluation.
Initial testing may include an electrocardiogram (EKG) which can help evaluate the heart rate and rhythm, electrical conduction within the heart, and whether hypertrophy or excess heart muscle has developed. A chest X-ray may help evaluate heart size and shape and may find excess fluid in the lungs due to abnormal heart function.
If further testing is required, often an echocardiogram (ultrasound) examination of the heart is helpful in visualizing the structures and functions of the heart. The echocardiogram can help to determine the specific diagnosis when a heart murmur is present. A cardiac catheterization is an invasive test whereby dye is injected directly into the blood passing through the heart structures to help evaluate their status.