抄録
Aim: It has been reported that impairment of left ventricular (LV) relaxation decreases early diastolic coronary blood flow rate (CBF). On the one hand, recent studies showed that mechanical vibration during diastole (diastolic vibration) accelerates LV relaxation rate instantly both in clinical settings and in experimental animals. Therefore, we examined whether diastolic vibration could increase diastolic CBF in regionally ischemic heart. Methods: In 9 open chest canine hearts, we narrowed the perfusion line to reduce total CBF to 50% of control. Applying 50Hz, 2mm amplitude diastolic vibration to the epicardium of the LV, we measured CBF, coronary perfusion pressure (CPP) and LV pressure. Results: Diastolic vibration shortened the time constant of the LV pressure fall (p<0.01), increased diastolic CBF (p<0.01) and decreased coronary vascular resistance (R) (p<0.01). The percentages of increase in diastolic CBF (p<0.05) and decrease in R (p<0.01) were larger in ischemia than in control. The percentages of increase in diastolic CBF (p<0.05) and decrease in R (p<0.01) were smaller with papaverine HCl injection (i. e; at attenuated vascular tone) than without injection. Diastolic vibration did not decrease systolic CBF. Conclusions: Diastolic vibration increased diastolic coronary blood flow rate and decreased coronary vascular resistance. We speculated that this was caused by the mechanism that diastolic vibration accelerates LV relaxation rate and dilates the coronary vasculature directly.
