Westmead Hospital, Sydney, Australia.
Circ Arrhythm Electrophysiol. 2013 Oct;6(5):1010-7. doi: 10.1161/CIRCEP.113.000348. Epub 2013 Sep 13.
Sudden arrhythmic death after myocardial infarction (MI) is most frequent in the first month. Early programmed ventricular stimulation (within 1 week) post-MI has been able to identify long-term ventricular tachycardia (VT) occurrence. We aimed to determine the timing of development and stabilization of VT circuits after MI and how the evolution of the underlying substrate differs with VT inducibility.
MIs were induced in 36 sheep. The 21 survivors underwent serial electroanatomic mapping and programmed ventricular stimulation. Animals were classified as VTpos (inducible VT) or VTneg (noninducible VT) at day 8. Forty-three percent of MI survivors were VTpos on day 8 (9/21), and all remained inducible on day 100 with 1.5 (1.0-2.0) and 1.0 (1.0-2.0) morphologies per animal on days 8 and 100, respectively. Twelve-lead electrocardiogram matched in 15 of 19 VTs between days 8 and 100. The earliest presystolic ventricular activations during VT circuits were in similar locations at the 2 time points. The 12 VTneg animals remained noninducible on day 100. There was no difference in voltage or velocity substrate with time or inducibility. The area with fractionated signals increased with time and VT inducibility. VTpos animals had more linear regions of slowed conduction forming conducting channels.
The inducibility and earliest presystolic endocardial activation sites of VT as well as voltage and velocity substrate on day 8 predicted those on day 100 postinfarct, indicating early formation and stabilization of the arrhythmogenic substrate. VT inducibility was influenced by the distribution of conducting channels and increased complex fractionated signals.
心肌梗死后（MI）的心律失常性猝死最常发生在第一个月内。MI 后早期程控心室刺激（1 周内）已能够识别长期室性心动过速（VT）的发生。我们旨在确定 MI 后 VT 回路的发展和稳定时间，以及潜在底物的演变如何随 VT 的可诱导性而不同。
在 36 只绵羊中诱导 MI。21 只幸存者进行了连续电解剖标测和程控心室刺激。在第 8 天，动物被分类为 VTpos（可诱导 VT）或 VTneg（不可诱导 VT）。43%的 MI 幸存者在第 8 天为 VTpos（9/21），所有幸存者在第 100 天仍可诱导，第 8 天和第 100 天每个动物的 VT 形态分别为 1.5（1.0-2.0）和 1.0（1.0-2.0）。在第 8 天和第 100 天，12 导联心电图在 19 次 VT 中有 15 次匹配。在这 2 个时间点，VT 回路中的最早心室提前激活位于相似位置。12 只 VTneg 动物在第 100 天仍不可诱导。随着时间的推移和可诱导性的变化，电压和速度底物没有差异。具有碎裂信号的区域随时间和 VT 的可诱导性增加而增加。VTpos 动物具有更多的线性慢传导区域，形成传导通道。
VT 的可诱导性和最早的心室提前心内膜激活部位以及第 8 天的电压和速度底物预测了第 100 天的结果，表明心律失常底物的早期形成和稳定。VT 的可诱导性受传导通道的分布和增加的复杂碎裂信号的影响。
