The hearts of three dogs, clinically diagnosed as having persistent atrial standstill syndrome (PAS), were studied post mortem. The most significant gross findings in the hearts of all three dogs were dilatation and marked reduction in the thickness of both atrial walls. Histopathologically, all three had widespread progressive loss of the atrial myocardium with replacement by fatty or fibrofatty tissue, consistent with atrial myopathy. The lesion mainly affected the upper half of both atria and was more severe in the epimyocardium and midmyocardium than in the endomyocardium. On the basis of these observations, it is proposed that the atrial myopathy commences in the upper regions of both atria and progresses downwards, as has been demonstrated electrophysiologically in PAS in humans, and extends from the epicardium towards the endocardium.

对临床诊断为持续性心房停顿综合征 (PAS) 的三只狗的心脏进行死后研究. 在所有三只狗的心脏中，最重要的总发现是扩张和两个心房壁厚度的显着减少。在组织病理学上，所有三人都具有广泛的心房心肌逐渐丧失，并被脂肪或纤维脂肪组织替代，这与心房肌病一致。病变主要影响两个心房的上半部分，并且在心肌外膜和心肌中层比在心内膜更严重。在这些观察的基础上，提出心房肌病从两个心房的上部区域开始并向下发展，正如在人类 PAS 中的电生理学所证明的那样，并从心外膜延伸到心内膜。