Correlates of the echocardiographic waves of the mitral valve in normal subjects of various ages.

A cardiographic study was performed on 71 subjects including 14 children, 42 young and middle-aged adults, and 15 old persons without evidence of heart disease. The echocardiogram of the mitral valve was recorded in the A mode by an analog method and was compared with the electrocardiogram, phonocardiogram, apex cardiogram, and carotid and jugular tracings, simultaneously obtained. The intervals between the various waves recorded by these methods were measured and the results were compared with those reported in the literature. A comparison of the duration of the intervals in the various age groups showed statistically significant differences. In particular, the intervals between the second heart sound and the peak of the E-wave and the E-F intervals in the echogram were longer in adults than in children and also longer in old persons than in younger adults. This important age difference should always be taken into account before attributing any echocardiographic deviations to disease.