The common origin of precordial vibrations

Abstract

The historical development of precordial vibration recording technics has been reviewed and the basic electronic principles outlined. Animal experiments were performed, in which left ventricular pressure curves were obtained simultaneously with precordial vibration tracings. An analog computer was utilized to derive a tracing resembling the vibrocardiogram from the pressure curve; a Krohn-Hite filter was used to obtain an apexcardiogram, a phonocardiogram and an accelerogram from the vibrocardiogram. It was demonstrated that a record closely resembling the left ventricular pressure tracing can be obtained by integration of the vibrocardiogram. The basic relationship of the precordial vibratory tracings to pressure changes within the left ventricle was demonstrated.