  Echocardiogram video segmentation plays an important role in cardiac disease
diagnosis. This paper studies the unsupervised domain adaption (UDA) for
echocardiogram video segmentation, where the goal is to generalize the model
trained on the source domain to other unlabelled target domains. Existing UDA
segmentation methods are not suitable for this task because they do not model
local information and the cyclical consistency of heartbeat. In this paper, we
introduce a newly collected CardiacUDA dataset and a novel GraphEcho method for
cardiac structure segmentation. Our GraphEcho comprises two innovative modules,
the Spatial-wise Cross-domain Graph Matching (SCGM) and the Temporal Cycle
Consistency (TCC) module, which utilize prior knowledge of echocardiogram
videos, i.e., consistent cardiac structure across patients and centers and the
heartbeat cyclical consistency, respectively. These two modules can better
align global and local features from source and target domains, improving UDA
segmentation results. Experimental results showed that our GraphEcho
outperforms existing state-of-the-art UDA segmentation methods. Our collected
dataset and code will be publicly released upon acceptance. This work will lay
a new and solid cornerstone for cardiac structure segmentation from
echocardiogram videos. Code and dataset are available at:
https://github.com/xmed-lab/GraphEcho
