Electrocardiogram (ECG) patterns of left anterior fascicular block and conduction impairment in ventricular myocardium: a whole-heart model-based simulation study

Left anterior fascicular block (LAFB) is a heart disease identifiable from an abnormal electrocardiogram (ECG). It has been reported that LAFB is associated with an increased risk of heart failure. Non-specific intraventricular conduction delay due to the lesions of the conduction bundles and slow cell to cell conduction has also been considered as another cause of heart failure. Since the location and mechanism of conduction delay have notable variability between individual patients, we hypothesized that the impaired conduction in the ventricular myocardium may lead to abnormal ECGs similar to LAFB ECG patterns. To test this hypothesis, based on a computer model with a three dimensional whole-heart anatomical structure, we simulated the cardiac exciting sequence map and 12-lead ECG caused by the block in the left anterior fascicle and by the slowed conduction velocity in the ventricular myocardium. The simulation results showed that the typical LAFB ECG patterns can also be observed from cases with slowed conduction velocity in the ventricular myocardium. The main differences were the duration of QRS and wave amplitude. In conclusion, our simulations provide a promising starting point to further investigate the underlying mechanism of heart failure with LAFB, which would provide a potential reference for LAFB diagnosis. the angulation of impaction having little effect on facture risk.摘要目的探究左前分支传导阻滞与心室肌传导速度减慢的 体表心电图之间相似之处,并探究其机理。创新点通过心电图仿真,证明了左心室前壁传导速度减 慢会形成类似左前分支阻滞的波形,并结合仿真 心脏电兴奋传导时序,对其机理进行了合理解 释。方法将真实人体心脏通过64 位螺旋计算机断层扫描 (CT),进行心脏解剖结构建模。通过单域模 型仿真出全心脏电兴奋的传导时序,然后利用边 界元法计算出各时刻人体体表电位,进而计算出 十二导联心电图。结论左心室前壁心肌细胞传导速度的减慢,会形成类 似左前分支阻滞的心电图波形,其主要区别是 QRS 波群的时间跨度以及幅度大小。