Fig. 1.

Algorithm initialization and atrioventricular plane definition. The user marks the atrioventricular (AV) plane by placing 8 input points to be tracked, here seen in red, in the end diastolic timeframe in the 2-, 3-, and 4-chamber long-axis views. In step 1 of the algorithm, the AV-plane is defined in the end diastolic timeframe of each long-axis view (white line), and the direction perpendicular to the AV-plane towards the apex (white arrow) marks the direction of the AV-plane displacement (AVPD). In step 2, the a priori position prediction is placed according to the defined plane and direction