Reconstruction of out-of-plane cardiac displacement patterns as observed on the chest wall during various phases of ECG by capacitance transducer

The out-of-plane displacements due to cardiac action were measured on the chest wall by an electronic distance measurement technique which is based on the variation of the capacitance between the probe and moving surface. The displacements were measured at 36 locations over the entire cardiac region along with ECG (electrocardiogram) measurements and were directly fed to an IBM PC/AT computer after analog-to-digital conversion. From these data, the displacement patterns for the whole region during the complete cardiac cycle could be reconstructed in a perspective view. The sequential analysis of the displacements shows the details of the cardiac events. and the results obtained are in agreement with other techniques. The averaged displacements over various regions of the heart for normal subjects are also presented. The data acquisition system and measurement results are presented and discussed.