The mitral valve opening phenomenon
Since the late 1970s, irregularities have been described in the descriptions of the opening and closing times of the mitral valve by various echocardiography modalities, and findings of the start of transmitral flow by Doppler have been described before showing a loss of coaptation of the mitral valves leaflets during diastolic suction36, an early mitral valve opening suggests a shorter duration of isovolumetric contraction37. More recently, MRI has documented, as previously discussed, that the start of elongation and detorsion by AS determines the opening of the mitral valve approximately 27 ms before the coaptations of the aortic valve24, this muscular action potentially triggering diastolic dysfunction, coinciding in experimental studies with the LV negative dP/dt pressure curve due to (Figure 4: 3A) AS contraction, which is the key point to identify the unwinding and elongation process19,20,27.
As we have seen, the BL causes clockwise recoil by rotating the apex with its subendocardial fibers and papillary muscles that connect the leaflets to the mitral annulus, (Figure 2: 4A) when it rotates counterclockwise due to DS contraction during ejection, it allows closure the mitral annulus, (Figure 2: 1A-B) (Figure 4: 3B-3C) to subsequently open again with the contraction of the AS that elongates and untwists the LV38(Figure 2: 3A-B) (Figure 4: 2C-3A) . Therefore, the mechanical explanation of mitral valve opening with LV elongation as a consequence of AS contraction poses a mechanical explanation for understanding diastolic dysfunction.