Key result
In vivo cinematographic analysis in dogs demonstrated that aortic valve closure begins before aortic flow deceleration and is at least 80% complete before aortic flow reaches zero.
High-speed cinematographic analysis in a canine model demonstrates that aortic valve closure begins prior to aortic flow deceleration and is largely complete before forward flow ceases.
Method enables direct aortic valve visualization in dogs; leaves open translation to human physiology.
In open-chest dogs direct-cinematographic high-speed recordings of aortic valve movement were made using a thin flexible fiberscope. Simultaneously ECG, ascending aortic flow (electromagnetically), and the pressures in the aorta, left ventricle, and left atrium were recorded. Replacement of blood by a transparent liquid (Tyrode solution) was done with two roller pumps, one connected to the left atrium and the other to the femoral artery. Free outflow occurred through a cannula in the pulmonary artery. Comparison of the film frames with the aortic flow signals revealed that 1) the valve was completely open at the moment that aortic flow had reached about 75% of its maximum value; 2) the opening time was 32 ms; 3) valve closure started before the onset of aortic flow deceleration; 4) at least 80% of the closure was completed before aortic flow becomes zero; 5) complete valve closing coincided with the moment of maximum backflow in the valve; 6) the shape of the valvular orifice at complete opening was almost circular; and 7) fluid viscosity had no significant effect on valve closure.
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Steenhoven et al. (1981) studied Aortic valve behavior (animal model). In vivo cinematographic analysis was evaluated on Aortic valve movement characteristics. In vivo cinematographic analysis in dogs demonstrated that aortic valve closure begins before aortic flow deceleration and is at least 80% complete before aortic flow reaches zero.
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