Clinical significance of cardiac murmurs: Get the sound and rhythm!

Murmurs arise when blood flow becomes turbulent, causing vibration of cardiovascular structures. Physiological murmurs or functional murmurs result from turbulent flow associated with normal blood flows at high velocity. Pathological murmurs are caused by a pathological condition such as valvular regurgitation or congenital cardiac disease. When a murmur is diagnosed, we first need to identify the source of the murmur and then assess its significance. We therefore need to classify murmurs based upon their timing (systolic or diastolic) and duration, location and radiation, intensity (1 to 6 scale) and character. The intensity of the murmur is often related to the severity of the regurgitation with louder murmurs being more severe. However, this is not always the case, especially not for a ventricular septal defect, for a musical murmur or when heart failure is present. The timing of the murmur, such as systolic (between S1 and S2), diastolic (between S2 and S1) or continuous, and the point of maximal intensity already allow to determine the origin of the murmur. The duration is described as early, mid, late, holoor pansystolic or –diastolic. Murmurs that obscure the normal heart sounds (pansystolic or pandiastolic) are more severe that those that do not obscure heart sounds (holosystolic or holodiastolic) The radiation and character are also related to the significance of the murmur.