Isovolumetric Relaxation.
It has been previously explained that during this badly named period, the whole heart does not relax but rather the AS contracts., There are records where the opening of the mitral valve begins with the unwinding and elongation of the LV (even with the aortic valve open) during this period, 50% to 60% of recoil and detorsion occur, promoting a drop in LV pressure below left atrial pressure, conditioning explosive LV suction, the interdependence of twisting and recoil is an essential interaction39, because twisting must stop before unwinding can begin. When an increase in DS contraction torsion occurs and isovolumetric relaxation time is prolonged, as in aortic stenosis, hypertension, and ischemia, diastolic dysfunction can develop40.