Department of Anatomy, Embryology, and Physiology, Academic Medical Center Amsterdam, Amsterdam, the Netherlands.
Cardiovasc Res. 2013 Jan 1;97(1):182-91. doi: 10.1093/cvr/cvs299. Epub 2012 Sep 20.
Transgenic mice are frequently used to investigate the role of genes involved in cardiac conduction. The QRS duration calculated from the electrocardiogram (ECG) is a commonly used measure for ventricular conduction time. However, the relation between ventricular activation and QRS duration calculated from a mouse surface ECG is not well understood. We aim to relate ventricular activation and repolarization patterns with the mouse ECG.
Ventricular activation and repolarization patterns generated by high-density optical mapping and a six-lead pseudo-ECG were compared in isolated mouse hearts. In addition, mouse ECGs were simulated in silico. Right-ventricular activation ends later than left-ventricular activation. Final activation coincided with the end of the QRS complex in leads III and aVF, but not in leads I, II, aVR, and aVL. The pattern of early repolarization (at 20% of repolarization, RT20) but not of RT50 or RT80 followed the activation pattern. After sodium channel blockade by ajmaline, total ventricular activation time increased by 10.0 ms, whereas QRS duration increased by only 2.1 ms. In mice carrying a mutation in Scn5a (1798insD), ventricular activation ended after the end of the QRS complex (12.9 ± 0.1 vs. 10.8 ± 0.3).
In the mouse, ventricular myocardium activation and early repolarization waves are simultaneously present. This hampers unequivocal interpretation of the duration of the QRS complex as a measure of ventricular activation duration, especially when conduction is slowed. Under these conditions mapping of local activation and repolarization patterns is required for correct interpretation of the ECG.
转基因小鼠常用于研究参与心脏传导的基因的作用。心电图（ECG）计算的 QRS 持续时间是心室传导时间的常用测量指标。然而，从鼠表面 ECG 计算的心室激活与 QRS 持续时间之间的关系尚未得到很好的理解。我们旨在将心室激活和复极模式与鼠 ECG 联系起来。
在分离的鼠心中，比较了高密度光学映射和六导联伪 ECG 产生的心室激活和复极模式。此外，还在计算机中模拟了鼠 ECG。右心室的激活晚于左心室的激活。终末激活与导联 III 和 aVF 中的 QRS 复合体结束一致，但在导联 I、II、aVR 和 aVL 中不一致。早期复极（复极 20%时，RT20）的模式而不是 RT50 或 RT80 的模式遵循激活模式。用阿马林钠阻断钠通道后，总心室激活时间增加了 10.0 ms，而 QRS 持续时间仅增加了 2.1 ms。在携带 Scn5a（1798insD）突变的小鼠中，心室激活在 QRS 复合体结束后结束（12.9 ± 0.1 比 10.8 ± 0.3）。
在鼠中，心室心肌激活和早期复极波同时存在。这使得难以将 QRS 复合体的持续时间作为心室激活持续时间的测量指标进行明确解释，特别是在传导减慢时。在这些情况下，需要映射局部激活和复极模式才能正确解释 ECG。
