[Relaxation of the left ventricle in aortic stenosis before and after aortal valve replacement]

In 14 patients with aortic valve disease (AVD) left ventricular (LV) relaxation was assessed by the time constant (T) of LV pressure (tipmanometer) fall before and 19 months after successful aortic valve replacement. 12 control patients were studied by the same technique. Preoperative LV ejection fraction in AVD (64%) and in controls (69%) did not differ. In AVD T was increased (60 ms) as compared to the controls (38 ms. p less than 0.05). During handgrip there was a similar increase in LV peak systolic pressure (LVSP), heart rate and peak measured contractile element velocity of shortening in AVD and in the controls. LV enddiastolic pressure varied minimally in both groups. T decreased during handgrip in controls (38 to 33 ms, p less than 0.01) and remained unchanged in AVD. Following aortic valve replacement resting T decreased insignificantly to 52 ms but remained increased (p less than 0.025) as compared to the controls. During postoperative handgrip, however, a decrease to 47 ms (p less than 0.05) was noted. Postoperative LVSP at rest (137 mm Hg) and LV muscle mass (105 g/m2) remained elevated (p less than 0.02) as compared to the controls (119 mm Hg; 72 g/m2). It is concluded that (1) in AVD with normal ejection performance LV relaxation at rest is prolonged, (2) the reaction of relaxation to handgrip is abnormal despite preserved contractile response, (3) following aortic valve replacement the response of LV relaxation to handgrip becomes normal and (4) elevated postoperative T at rest appears to be related to still increased LVSP postoperatively and residual hypertrophy rather than to intrinsic disturbances of myocardial relaxation.