Angel Nathan, Kholmovski Eugene G, Ghafoori Elyar, Dosdall Derek J, MacLeod Rob S, Ranjan Ravi
Division of Cardiovascular Medicine, University of Utah, Salt Lake City, UT, United States of America.
Department of Biomedical Engineering, University of Utah, Salt Lake City, UT, United States of America.
Comput Cardiol (2010). 2019 Sep;46. doi: 10.22489/cinc.2019.403. Epub 2020 Feb 24.
Regions within the atria with sustained rapid reentrant or focal activity have been defined as a mechanism of persistent atrial fibrillation (AF). However, the mechanism behind the anchoring of these sites and their stability over time is unknown. We tested the hypothesis that fibrosis anchors sites of high frequency activation during AF and that these sites can be non-invasively determined using cardiac T1 Mapping with MRI. A canine rapid atrial paced model of persistent AF was used (n=12, including 6 controls) for the study. Whole heart T1 Mapping was performed prior to an electrical mapping study. Spatial maps of high dominant frequency (DF) probability were constructed to determine stability of the highest DF sites. These sites were then correlated with fibrotic regions determined by T1 Mapping. The chronic AF animals had at least one site of stable, high DF for at least 22.5 (75%) of 30 minutes of AF. Regions of stable high DF bordered regions of fibrosis as determined by T1 Mapping MRI 82% of the time (p<0.05). Heterogeneous atrial remodeling, specifically fibrosis, arising from chronic AF may provide a substrate that anchors sites of high DF. Cardiac T1 Mapping with MRI may determine such sites non-invasively.
心房内具有持续快速折返或局灶性活动的区域已被定义为持续性心房颤动（AF）的一种机制。然而，这些部位锚定的背后机制及其随时间的稳定性尚不清楚。我们测试了这样一个假设，即纤维化在房颤期间锚定高频激活部位，并且这些部位可以使用心脏磁共振成像（MRI）的T1映射进行无创测定。本研究使用了犬类持续性房颤快速心房起搏模型（n = 12，包括6只对照犬）。在进行电标测研究之前进行了全心T1映射。构建高主导频率（DF）概率的空间图以确定最高DF部位的稳定性。然后将这些部位与通过T1映射确定的纤维化区域相关联。慢性房颤动物在房颤30分钟的至少22.5（75%）分钟内有至少一个稳定的高DF部位。通过T1映射MRI确定，82%的时间里稳定高DF区域与纤维化区域相邻（p<0.05）。由慢性房颤引起的异质性心房重塑，特别是纤维化，可能提供了一个锚定高DF部位的基质。心脏MRI的T1映射可能无创地确定这些部位。
