The atrioventricular node, or AV node, is a tiny group of specialized cardiac cells located in the lower part of the right atrium, near the septum dividing the atria from the ventricles. Its primary function is to receive electrical impulses from the atria and briefly delay them before passing them on to the ventricles, ensuring that the atria finish contracting before the ventricles begin. While the AV node itself is too small to be seen on ultrasound, its function directly affects what sonographers observe during echocardiography, including the timing of valve movements, Doppler flow patterns, and heart rhythm. Problems with the AV node can cause heart block, a condition where electrical signals are delayed or blocked from reaching the ventricles.
Sonography Term