Zeller Amy, Ghoraani Behnaz
Department of Biomedical Engineering, Rochester Institute of Technology, Rochester, NY, USA.
Open Cardiovasc Med J. 2015 Feb 27;9:26-34. doi: 10.2174/1874192401509010026. eCollection 2015.
T-Wave alternans (TWA) testing using 12-lead electrocardiogram/Frank leads is emerging as an important non-invasive biomarker to identify patients at high risk of Sudden Cardiac Death (SCD). Cardiac scarring is very common among cardiomyopathy patients; however, its influence on the body surface distribution of TWA has not yet been defined. Our objective was to perform a simulation study in order to determine whether cardiac scarring affects the distribution of TWA on thorax such that the standard leads fail to detect TWA in some of cardiomyopathy patients; thereby producing a false-negative test. Developing such a novel lead configuration could improve TWA quantification and potentially optimize electrocardiogram (ECG) lead configuration and risk stratification of SCD in cardiomyopathy patients. The simulation was performed in a 1500-node heart model using ECGSIM. TWA was mimicked by simulating action potential duration alternans in the ventricles. Cardiac scarring with different sizes were simulated by manipulating the apparent velocity, transmembrane potential and transition zone at varied locations along the left ventricular posterior wall. Our simulation study showed that the location of maximum TWA depends on the location and size of the myocardium scarring in patients with cardiomyopathy, which can give rise to false-negative TWA signal detection using standard clinical leads. The TWA amplitude generally increased with the increment of scar size (P<0.00001). We found one specific location (a non-standard lead) that consistently appeared as the top five maximum TWA leads and could be considered as an additional lead to improve the outcome of the TWA testing in cardiomyopathy patients.
使用12导联心电图/Frank导联进行T波交替（TWA）检测正逐渐成为一种重要的非侵入性生物标志物，用于识别心脏性猝死（SCD）高危患者。心肌瘢痕在心肌病患者中非常常见；然而，其对TWA体表分布的影响尚未明确。我们的目的是进行一项模拟研究，以确定心肌瘢痕是否会影响TWA在胸部的分布，从而导致标准导联在某些心肌病患者中无法检测到TWA；进而产生假阴性检测结果。开发这样一种新颖的导联配置可以改善TWA定量，并有可能优化心肌病患者心电图（ECG）导联配置和SCD风险分层。使用ECGSIM在一个1500节点的心脏模型中进行模拟。通过模拟心室动作电位时程交替来模拟TWA。通过操纵沿左心室后壁不同位置的表观速度、跨膜电位和过渡区来模拟不同大小的心肌瘢痕。我们的模拟研究表明，心肌病患者中最大TWA的位置取决于心肌瘢痕的位置和大小，这可能导致使用标准临床导联检测到假阴性TWA信号。TWA幅度通常随瘢痕大小的增加而增加（P<0.00001）。我们发现一个特定位置（一个非标准导联）始终作为TWA最大的前五导联出现，可以被视为一个额外的导联，以改善心肌病患者TWA检测的结果。
