Voss Frederik, Steen Henning, Bauer Alexander, Giannitsis Evangelos, Katus Hugo A, Becker Ruediger
Department of Cardiology, University of Heidelberg, Heidelberg, Germany.
Heart Rhythm. 2008 Feb;5(2):308-14. doi: 10.1016/j.hrthm.2007.10.026. Epub 2007 Oct 18.
Once chamber geometry is determined, the EnSite 3000 noncontact mapping system can create a voltage map during a single cardiac cycle. The EnSite uses an inverse solution to the Laplace equation to process the amplified far-field signals from the noncontact catheter. This process creates a three-dimensional endocardial potential map from a single cardiac cycle. Dynamic substrate mapping (DSM) is an algorithm designed to identify conduction boundaries, such as myocardial scars based on voltage distribution within the corresponding chamber.
The purpose of this study was to investigate the correlation between DSM- and magnetic resonance imaging (MRI)-determined scar areas and to identify a suitable DSM voltage threshold.
A total of eight dogs were studied. Four healthy foxhounds underwent ligation of the left anterior descending coronary artery. Evidence of myocardial infarction, including ECG changes and elevated cardiac troponin T levels, was noted in all animals. Cardiac MRI scan was performed 29 +/- 2 days after ligation of the left anterior descending coronary artery. Subsequently, noncontact mapping of the left ventricle was obtained in each dog, and myocardial infarction size was determined using DSM at different filter settings. As a control group, another four foxhounds underwent sham thoracotomy/pericardiotomy.
A significant linear correlation of infarction size using DSM compared with MRI measurements was found at the filter setting "peak negative 34%" (P = .001, r = 0.99). Mean relative infarction size was 15.9% +/- 4.5% with DSM and 16.0% +/- 4.2% with MRI. Compared with the sham group, a significant reduction in left ventricular ejection fraction was found after ligation of the left anterior descending coronary artery (51.0% +/- 3.8% vs 69.2% +/- 5.9%, P = .002). Pathoanatomic studies were performed to confirm the measured infarct dimensions. No scars were detectable in sham-operated dogs using DSM or MRI.
Noncontact mapping allows identification of scar tissue within the left ventricle. An excellent correlation was observed between DSM-scar surface and MRI-determined scar size. Identifying and marking these areas can be useful when planning an ablation strategy in the clinical setting of ischemic heart disease.
一旦确定心腔几何形状，EnSite 3000非接触式标测系统就能在单个心动周期内创建电压图。EnSite使用拉普拉斯方程的逆解来处理来自非接触导管的放大远场信号。这一过程从单个心动周期创建三维心内膜电位图。动态基质标测（DSM）是一种算法，旨在根据相应心腔内的电压分布识别传导边界，如心肌瘢痕。
本研究旨在探讨DSM与磁共振成像（MRI）确定的瘢痕面积之间的相关性，并确定合适的DSM电压阈值。
共研究8只犬。4只健康猎狐犬接受左前降支冠状动脉结扎。所有动物均出现心肌梗死证据，包括心电图改变和心肌肌钙蛋白T水平升高。在左前降支冠状动脉结扎后29±2天进行心脏MRI扫描。随后，对每只犬进行左心室非接触式标测，并在不同滤波设置下使用DSM确定心肌梗死大小。作为对照组，另外4只猎狐犬接受假开胸/心包切开术。
在滤波设置“峰值负34%”时，发现使用DSM测量的梗死面积与MRI测量结果存在显著线性相关性（P = 0.001，r = 0.99）。DSM测量的平均相对梗死面积为15.9%±4.5%，MRI测量的为16.0%±4.2%。与假手术组相比，左前降支冠状动脉结扎后左心室射血分数显著降低（51.0%±3.8%对69.2%±5.9%，P = 0.002）。进行病理解剖学研究以确认测量的梗死尺寸。在假手术犬中，使用DSM或MRI均未检测到瘢痕。
非接触式标测可识别左心室内的瘢痕组织。DSM瘢痕表面与MRI确定的瘢痕大小之间观察到极好的相关性。在缺血性心脏病临床环境中规划消融策略时，识别和标记这些区域可能有用。
