Diastolic property of left ventricle under experimental volume overload

Diastolic property of left ventricle (LV) was estimated by the passage of time using an experimental model of volume overload. Volume overload was surgically induced in dogs by means of bradycardia (complete A-V block). LV dimension and LV pressure were simultaneously recorded and pressure-volume curve (P-V curve) was obtained at the three stages, i.e., just after the creation of bradycardia; 8 approximately 14 days after the operation; and 2 approximately 4 months after the operation. The rightward shift of P-V curve was confirmed as being associated with the development of eccentric hypertrophy; but this study showed no significant changes in indices of LV chamber elasticity. Indices of muscle elasticity derived from myocardial stress-strain (sigma-epsilon) relationship also remained constant in the three stages. It was demonstrated that the shift of the P-V curve resulted neither from the changes of LV chamber elasticity, nor myocardial elasticity.