Magnet noncontact apexcardiography. A new technique for registering chest motion

A new apexcardiographic recording system has been developed which is free of certain technical limitations. This noncontact magnetic transducer was tested alternately with a commonly used pneumatic piezoelectric transducer in a comparative study on ten normal subjects. The magnetic registration offered a more accurate timing and configuration of the ACG. Signal distortion, such as peaked waves and an early fall of the systolic wave, was eliminated. The magnetic transducer was capable of recording directional apex point tracings, as well as pulsations of a larger apical area. The new system proved to possess definite advantages and eliminated some of the inconveniences inherent in the pneumatically coupled system.