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BACKGROUND	Intraventricular fluid dynamics can be assessed clinically using imaging .
BACKGROUND	The contribution of vortex structures to left ventricular ( LV ) diastolic function has never been quantified in vivo .
OBJECTIVE	This study sought to understand the impact of intraventricular flow patterns on filling and to assess whether impaired fluid dynamics may be a source of diastolic dysfunction .
METHODS	Two-dimensional flow velocity fields from color Doppler echocardiographic sequences were obtained in 20 patients with nonischemic dilated cardiomyopathy ( NIDCM ) , 20 patients with hypertrophic cardiomyopathy ( HCM ) , and 20 control healthy volunteers .
METHODS	Using a flow decomposition method , we isolated the rotational velocity generated by the vortex ring from the surrounding flow in the left ventricle .
RESULTS	The vortex was responsible for entering 13 6 % of filling volume in the control group and 19 8 % in the NIDCM group ( p = 0.004 ) , but only 5 5 % in the HCM group ( p < 0.0001 vs. controls ) .
RESULTS	Favorable vortical effects on intraventricular pressure gradients were observed in the control and NIDCM groups but not in HCM patients .
RESULTS	Differences in chamber sphericity explained variations in the vortex contribution to filling between groups ( p < 0.005 ) .
CONCLUSIONS	The diastolic vortex is responsible for entering a significant fraction of LV filling volume at no energetic or pressure cost .
CONCLUSIONS	Thus , intraventricular fluid mechanics are an important determinant of global chamber LV operative stiffness .
CONCLUSIONS	Reduced stiffness in NIDCM is partially related to enhanced vorticity .
CONCLUSIONS	Conversely , impaired vortex generation is an unreported mechanism of diastolic dysfunction in HCM and probably other causes of concentric remodeling .

