Indirect Measurement of Isovolumetric Contraction Time on the Basis of Polygraphic Tracing

Abstract

A correct and simple method for the measurement of isovolumetric contraction time (IVCT) on the basis of apexcardiogram (ACG), carotid tracing (CT) and phonocardiogram is discussed. IVCT is equal to the interval from the onset of the systolic wave in the ACG to the onset of the GT, minus the delay time of the central pulse wave (from the beginning of the 2nd aortic sound to the carotid incisura). The E point in the left ventricular ACG, i. e. the point which represents the opening of the aortic valves or the end of the IVCT, usually precedes the peak of the systolic wave in the ACG.