Bhagirath Pranav, van der Graaf Maurits, van Dongen Elise, de Hooge Jacques, van Driel Vincent, Ramanna Hemanth, de Groot Natasja, Götte Marco J W
Department of Cardiology, Haga Teaching Hospital, The Hague, The Netherlands (P.B., M.G., E.D., J.H., V.D., H.R., M.W.).
Department of Cardiology, Erasmus Medical Centre, Rotterdam, The Netherlands (N.G.).
J Am Heart Assoc. 2015 Oct 14;4(10):e002222. doi: 10.1161/JAHA.115.002222.
Inverse potential mapping (IPM) noninvasively reconstructs cardiac surface potentials using body surface potentials. This requires a volume conductor model (VCM), usually constructed from computed tomography; however, computed tomography exposes the patient to harmful radiation and lacks information about tissue structure. Magnetic resonance imaging (MRI) is not associated with this limitation and might have advantages for mapping purposes. This feasibility study investigated a magnetic resonance imaging-based IPM approach. In addition, the impact of incorporating the lungs and their particular resistivity values was explored.
Three volunteers and 8 patients with premature ventricular contractions scheduled for ablation underwent 65-electrode body surface potential mapping. A VCM was created using magnetic resonance imaging. Cardiac surface potentials were estimated from body surface potentials and used to determine the origin of electrical activation. The IPM-defined origin of sinus rhythm corresponded well with the anatomic position of the sinus node, as described in the literature. In patients, the IPM-derived premature ventricular contraction focus was 3-dimensionally located within 8.3±2.7 mm of the invasively determined focus using electroanatomic mapping. The impact of lungs on the IPM was investigated using homogeneous and inhomogeneous VCMs. The inhomogeneous VCM, incorporating lung-specific conductivity, provided more accurate results compared with the homogeneous VCM (8.3±2.7 and 10.3±3.1 mm, respectively; P=0.043). The interobserver agreement was high for homogeneous (intraclass correlation coefficient 0.862, P=0.003) and inhomogeneous (intraclass correlation coefficient 0.812, P=0.004) VCMs.
Magnetic resonance imaging-based whole-heart IPM enables accurate spatial localization of sinus rhythm and premature ventricular contractions comparable to electroanatomic mapping. An inhomogeneous VCM improved IPM accuracy.
逆电位标测（IPM）利用体表电位无创地重建心脏表面电位。这需要一个容积导体模型（VCM），通常由计算机断层扫描构建；然而，计算机断层扫描会使患者暴露于有害辐射且缺乏组织结构信息。磁共振成像（MRI）不存在此限制，并且可能在标测方面具有优势。本可行性研究探讨了基于磁共振成像的IPM方法。此外，还研究了纳入肺部及其特定电阻率值的影响。
三名志愿者和八名计划进行消融的室性早搏患者接受了65电极体表电位标测。使用磁共振成像创建了一个VCM。从体表电位估计心脏表面电位，并用于确定电激动的起源。IPM确定的窦性心律起源与文献中描述的窦房结解剖位置吻合良好。在患者中，IPM得出的室性早搏起源在使用电解剖标测侵入性确定的起源的三维范围内，距离为8.3±2.7毫米。使用均匀和非均匀VCM研究了肺部对IPM的影响。与均匀VCM相比，纳入肺部特定电导率的非均匀VCM提供了更准确的结果（分别为8.3±2.7和10.3±3.1毫米；P=0.043）。对于均匀（组内相关系数0.862，P=0.003）和非均匀（组内相关系数0.812，P=0.004）VCM，观察者间一致性较高。
基于磁共振成像的全心IPM能够实现与电解剖标测相当的窦性心律和室性早搏的精确空间定位。非均匀VCM提高了IPM的准确性。
