CONTRAST ECHOCARDIOGRAPHY FOR EVALUATION OF LEFT-VENTRICULAR FLOW DYNAMICS USING DENSITOMETRIC ANALYSIS

Background. Few data exist regarding intraventricular flow patterns in the presence of left ventricular dysfunction. Therefore, we examined the relation between intracavitary left ventricular flow dynamics and the presence of ventricular contractile abnormalities using videodensi tometric analysis of transpulmonary contrast echocardiography. Methods and Results. Two-dimensional echocardiography was performed before, d uring, and after intravenous injection of sonicated albumin in 8 norma l subjects, 22 patients with infarction, and 6 patients with dilated c ardiomyopathy. Time-intensity curves were recorded, and disappearance half-times (in cardiac cycles) were measured for regions of interest a t the mitral orifice (Ta) and mid-left ventricular cavity (Tb). We obs erved contrast enhancement of the left ventricular cavity in 28 of 36 patients. Ta and Th were identical (19 beats) in all normal patients, but Tb was greater than Ta (19 versus 22 beats, P<.001) in patients wi th dyssynergy. Patients with dyssynergy were divided in three groups: group A, in whom Tb-Ta less-than-or-equal-to 3; group B, in whom Th-Ta greater-than-or-equal-to 4; and group C, which was composed of patien ts without contrast enhancement. Left ventricular end-diastolic dimens ion was similar in normal patients (46.1 mm) and group A patients (50. 3 mm) but was less in each cohort than in groups B (58.7 mm) and C (64 .1 mm) (all P<.01). Significant correlation was observed between Tb-Ta and both ejection fraction (r=-.67, P<.001) and wall motion index (r= .62, P<.001). Conclusions. Clearance of contrast from the mid-left ven tricular cavity is prolonged in patients with left ventricular dysfunc tion. This prolongation may be related to increased left ventricular d iastolic volume, impaired intracavitary mixing, or paradoxical systoli c flow. Delayed left ventricular contrast washout may have implication s regarding the formation of left ventricular thrombi.