SIMULATION STUDY ON THE EFFECT OF EXTERNAL VIBRATION ON LEFT-VENTRICULAR FUNCTION - POTENTIAL INDICATOR OF LV TOLERANCE TO THE SUDDEN REDUCTION OF MYOCARDIAL-CONTRACTILITY

In a previous study the authors reported that external mechanical vibr ation applied to the left ventricular (LV) epicardium induces contract ility-dependent depression in in LV pressure, stoke volume and stroke work. It was suggested that this depression may be caused by the direc t effect of external vibration on contractile protein. In another pape r in this issue, it is proved that LV function with various myocardial contractilities and the actual process of deterioration in heart fail ure are well simulated in the model proposed by Beyar and Sideman, aft er some modifications have been made. In the study reported here it is assumed that an external mechanical vibration induces sudden reductio n in myocardial active stress in the model of Beyar and Sideman; in th is way the contractility-dependent effect of external vibration on LV function has been simulated. The results of this simulation support th e suggestion that external mechanical vibration directly affects contr actile protein and reduces LV function, and it is further suggested th at the reduction of LV function induced by external vibration reflects the reserve or tolerance capacity of LV to a sudden reduction of myoc ardial contractility.