Noise accompanying the heart beat that indicates abnormal turbulences in the bloodstream within the heart. In a healthy, normal heart the blood flows with some turbulence; defects such as leakage through a valve or a hole in the heart alter the flow pattern, thus causing an abnormal noise. Any valve abnormality causes a characteristic noise, identified by the moment and the place at which it is best heard with a stethoscope. If a valve is constricted, the sound is produced as the blood passes through it – in the systole (contraction) therefore if the aortal or pulmonary valves are constricted, and in the diastole (relaxation) if the problem lies in the mitral or tricuspid valves. A leaking valve causes noise when it should be tightly closed: in the diastole for the aortal or pulmonary valves, and in the systole for the mitral or tricuspid valves. A hole in the atrial or ventrical septum produces noise in the systole. By no means every noise is a sign of heart abnormality; in children in particular, quite innocent noises may be produced.