Left ventricular vortices as observed by vector flow mapping: main determinants and their relation to left ventricular filling.

ABSTRACT

BACKGROUND: Swirling flow, organized in vortices, contributes to adequate left ventricular function. In this study, we apply a novel echocardiographic flow-mapping technique, vector flow mapping (VFM), to evaluate the main characteristics of left ventricular vortices and its relation to filling parameters. METHODS: Forty-eight subjects underwent conventional transthoracic echocardiographic examination with additional intracardiac flow assessment with VFM using a Aloka Alpha-10 system and experimental VFM analysis software. To analyze vortex behavior, its rotation direction, duration, location inside the left ventricle, size, and intensity were assessed in apical long-axis view. Its relation to conventional left ventricular filling parameters was then analyzed. RESULTS: Two vortex components were consistently identified following each transmitral filling wave. The anterior component of these visualized vortices was analyzed, due to its higher significance in the cardiac cycle, following early filling (V1) and atrial contraction (V2). Differences were observed in several aspects of vortex behavior between V1 and V2, particularly in patients with normal left ventricular filling parameters. These differences may be related to varying roles of vortices in different periods of the cardiac cycle. CONCLUSIONS: Vector flow mapping allowed visualization and measurement of several parameters defining vortex behavior inside the cardiac cycle. The differences observed in these parameters between vortices in different phases of the cardiac cycle may be related to their role in optimizing cardiac function.