Phonocardiographic evaluation of total artificial heart valve movement. Correlation with pressure waveforms

Two categories of inflow and outflow valve closure sounds are present in the Jarvick-7 model of the Utah total artificial heart. A presystolic inflow valve closure sound occurs at the end of ventricular filling, resulting from a transient rise in intraventricular pressure above that in the atrium. A second inflow valve closure sound follows, associated with the onset of mechanical systole with a rapid rise in intraventricular pressure. A mid- to late systolic outflow valve closure sound occurs at the end of ventricular ejection, resulting from a transient fall in intraventricular pressure below that in the aorta. A second outflow valve closure sound follows, associated with the onset of mechanical diastole with a rapid fall in intraventricular pressure. Under operating conditions where either ventricular filling or ejection is not complete, the presystolic and midsystolic sounds are absent. Thus, regulated heart driver parameters as well as preload and afterload to the extent that they influence ventricular filling and emptying will determine the presence and sequence of valve sounds.