频发室性早搏所致心肌病易发心源性猝死的电生理机制研究

Frequent premature ventricular complexes (PVCs) can cause cardiomyopathy and heart failure, and even increase the possibility of sudden cardiac death (SCD). The electrophysiological mechanism by which frequent PVCs induce ventricular electrophysilogical remodeling resulting in SCD is not well-known.We have established a heart failure model induced by fast ventricular pacing and PVCs respectively, and developed a technology to perform simutaneous electrical mapping for right and left ventricles. The aims of this project are as follows.1)Simulate PVCs-induced cardimyopathy and cardiac dysfunction by right ventriculr pacing with a special pacing program. 2)Evaluate dispersion of refractoriness, restitution properities, and activation patterns during ventricular fibrillation by simutaneous electrical mapping in a canine model of frequent PVCs-induced cardiomyopathy. 3)Re-evaluate the change of the substrate of SCD including dispersion of refractoriness, restitution properities, and activation patterns during ventricular fibrillation after PVCs is eliminated and cardiac function is reversible. The results of the current study might indicate the possible electrophysiological mechanism and key pathway of SCD caused by frequent PVCs-induced cardiomyopathy and cardiac dysfunction. Also, it will provide experimental evidence for the management of SCD by intervention or medications to eleminate PVCs in future.

频发室性早搏可致心肌病和心功能不全，从而增加心源性猝死风险。但是，频发室性早搏导致心室电生理重构，以致并发心源性猝死的电生理机制仍未明确。本研究小组在成功建立快速右室起搏致心力衰竭模型、建立频发室性早搏致心力衰竭模型和开发双心室同步电生理标测技术平台的基础上，本项目拟进一步研究：1）利用特定起搏程控方案，通过右室心尖部起搏模拟频发室性早搏诱发心肌病和心功能不全；2）利用双心室同步标测技术，评估频发室性早搏致心功能不全后，不应期离散度、不应期整复性以及心室颤动激动特征的变化；3）消除室性早搏，心功能逆转后，评估不应期离散度、不应期整复性以及心室颤动激动特征等心源性猝死的电生理基质是否随之消失。通过本项研究，可为频发室性早搏致心功能不全并发心源性猝死的电生理机制和主要作用途径提供重要线索，为今后介入或药物等方法消除室性早搏以逆转心功能，防治心源性猝死提供实验依据，项目具有重要的理论和现实意义。

频发室性早搏可致心肌病和心功能不全，潜在增加心源性猝死风险。本项研究在成功建立快速右室起搏致心力衰竭模型、建立频发室性早搏致心力衰竭模型和开发双心室同步电生理标测技术平台的基础上，做了一下进一步研究：1）利用特定起搏程控方案，通过右室心尖部起搏模拟频发室性早搏诱发心肌病和心功能不全；2）利用双心室同步标测技术，评估频发室性早搏致心功能不全后，发现不应期离散度和不应期整复性曲线斜率增大，同时评估心室颤动激动特征的变化；3）在消除室性早搏，心功能可逆转，不应期离散度较心衰时降低、不应期整复性曲线斜率降低，提示消除室早有利于消除心源性猝死的电生理基质。通过本项研究，对防治频发室性早搏致心功能不全并发心源性猝死提供了实验依据，项目具有一定的现实意义。