UCLA Cardiac Arrhythmia Center, David Geffen School of Medicine at UCLA, Los Angeles, California, USA.
Heart Rhythm. 2010 Mar;7(3):389-95. doi: 10.1016/j.hrthm.2009.11.023. Epub 2009 Dec 2.
The presence of epicardial fat can confound the quantification of scar during transpericardial electroanatomic mapping. The electrogram (EGM) characteristics of epicardial fat have not been systematically compared with infarct scar using gross and histopathological analysis as a gold standard.
The purpose of this study was to compare the EGM characteristics of epicardial fat with infarct scar.
A closed-chest infarction was created in 40-50 kg pigs by occlusion of the circumflex artery for 150 minutes using an angioplasty balloon. This artery was chosen to minimize any potential overlap of epicardial fat with infarct and to spare any septal involvement. After 4-12 weeks of infarct healing, epicardial mapping was performed. EGMs in low-voltage regions (<1.5 mV) were analyzed, and bipolar amplitude, duration, number of deflections, and the presence of late potentials were recorded. Statistical analysis was performed using unpaired t-test and chi(2) analysis. Gross and histopathological examination was used to confirm areas of fat and infarct scar.
Seven porcine hearts were analyzed after high-density epicardial mapping (364 +/- 92 points) was performed 48 +/- 19 days after infarction. The mean bipolar EGM amplitude was similar in fat and scar (0.77 +/- 0.34 vs. 0.75 +/- 0.38 mV; P = not significant). The mean EGM duration was longer in scar than in fat (68.8 +/- 18.9 vs. 50.1 +/- 11.6 ms; P <.0001) and exhibited more fractionation (8.5 +/- 3.1 vs. 4.7 +/- 1.8 deflections; P <.0001). The presence of late potentials was 99% specific for scar. Further, areas of fat >4 mm in thickness registered low-voltage bipolar EGMs.
Scar from healed myocardial infarction exhibits more fractionation and longer EGM duration when compared with fat. Late potentials are highly specific for locating infarct scars.
心外膜脂肪的存在会干扰透壁性心外膜电解剖标测中的瘢痕定量。尚未系统地使用大体和组织病理学分析作为金标准比较心外膜脂肪与梗死瘢痕的电图形（EGM）特征。
本研究旨在比较心外膜脂肪与梗死瘢痕的 EGM 特征。
采用球囊血管成形术闭塞回旋支动脉 150 分钟，在 40-50 公斤猪中建立闭胸性梗死。选择该动脉以尽量减少心外膜脂肪与梗死区的任何潜在重叠，并避免任何间隔受累。梗死愈合 4-12 周后，进行心外膜标测。分析低电压区（<1.5 mV）的 EGM，并记录双极振幅、持续时间、偏转数和晚期电位的存在。使用配对 t 检验和卡方分析进行统计学分析。使用大体和组织病理学检查确认脂肪和梗死瘢痕区域。
在梗死 48 ± 19 天后进行高密度心外膜标测（364 ± 92 个点）后分析了 7 只猪心。脂肪和瘢痕中的平均双极 EGM 振幅相似（0.77 ± 0.34 与 0.75 ± 0.38 mV；P = 无显著差异）。瘢痕中的 EGM 持续时间长于脂肪（68.8 ± 18.9 与 50.1 ± 11.6 ms；P <.0001），并且具有更多的分节（8.5 ± 3.1 与 4.7 ± 1.8 个偏转；P <.0001）。晚期电位对于瘢痕的特异性为 99%。此外，厚度>4 毫米的脂肪区域记录到低电压双极 EGM。
与脂肪相比，愈合性心肌梗死的瘢痕具有更多的分节和更长的 EGM 持续时间。晚期电位对于定位梗死瘢痕具有高度特异性。
