Influence of respiration on recording cardiac potentials. Isopotential surface-mapping and vectorcardiographic studies.

Abstract Isopotential surface-mapping studies in normal children indicated that inspiration produces an inferior shift of potential maxima and minima on the body surface with a concomitant decrease in their absolute potential values. There was a terminal maximum under the right clavicle with inspiration which was absent during expiration. Review of the body surface potential distribution provided a clearer picture of changing events of respiration than could be acquired from analysis of data acquired from a few selected points, as is done in vector-cardiography. Respiratory changes were more prominent in abnormal than in normal vector-cardiograms. It is suggested that when quantitative vectorcardiographic analysis is used for comparison of patient groups, it would be optimal to compare beats recorded during resting expiration.