Sub-xiphoid echocardiography--a new approach to the diagnosis and differentiation of atrioventricular defects.

Abstract

M-Mode echocardiography provides a non-invasive technique with which to analyse atrioventricular valve status and atrioventricular junction anatomy. The parasternal approach is limited in this respect as it does not profile the inlet ventricular septum. Examination of autopsy specimens suggested that the sub-xiphoid approach should selectively profile the inlet septum and its relationships to the atrioventricular valves. We have developed a composite M-Mode sub-xiphoid scan and assessed its value in the analysis of the atrioventricular junction in 107 children with normal hearts and 71 children with documented atrioventricular defects (34 partial, 37 complete). The latter group was studied both by parasternal and sub-xiphoid approaches to compare the relative values of the two methods in differentiating complete from partial defects. The parasternal approach failed to identify the correct atrioventricular junction anatomy in 15 cases. In contrast, sub-xiphoid M-Mode scanning predicted the correct atrioventricular junction anatomy in all 71 cases, allowing visualization of the common atrioventricular valve and inlet ventricular septal defect where these were present. It is concluded that the sub-xiphoid approach is the M-Mode echocardiographic technique of choice in differentiating between partial and complete forms of atrioventricular defects offering an increase in diagnostic accuracy over both left-ventricular cine-angiography and parasternal M-Mode echocardiographic scanning.