Reproducibility of the systolic and diastolic energy loss of the left ventricle in vector flow mapping.

Abstract

Background: Vector Flow Mapping (VFM) is a novel technique for visualizing intracardiac blood flow. A few reports have been made regarding the reproducibility of energy loss (EL) measurements using VFM. This study aims to elucidate the intra-class and inter-class correlation coefficient (intra-ICC and inter-ICC) in the EL measurements.

Methods: Seven healthy participants were enrolled, and echocardiographic data were obtained by two cardiac sonographers (14 images). Three independent analysts analyzed all images in three different cardiac cycles three times: 378 data points (14 images × analysts × 3 cardiac cycles × 3 times). The intra-ICC (1, 1) and inter-ICC (2, 1) were calculated. Furthermore, the intra-ICC (1, k) and inter-ICC (2, k) were applied using the averaged EL value in three cardiac cycles. An ICC value greater than 0.75 was defined as acceptable reproducibility.

Results: In diastole, the intra-ICC (1, 1) by the three analysts was 0.890, 0.830, and 0.802; the intra-ICC (1, k), using the average EL value was 0.986, 0.978, and 0.973. In systole, the intra-ICC (1, 1) was 0.729, 0.698, and 0.733; the intra-ICC (1, k) was 0.960, 0.954, and 0.961. In diastole, the inter-ICC (2, 1) was 0.950, and the inter-ICC (2, k) was 0.958. In contrast, in systole, the inter-ICC (2, 1) was 0.772, and the inter-ICC (2, k) was 0.774; these values were lower than those in diastole.

Conclusions: These findings indicate that the intra- and inter-measurer reproducibility of diastolic and systolic EL is favorable for clinical use.