Deng Juelin, Chen Mao, Yang Qing, Yu Houzhi, Zhang Tao, Yu Qian, Huang Dejia
Department of Geriatric, West China Hospital, Sichuan University, Chengdu 610041, China.
Sheng Wu Yi Xue Gong Cheng Xue Za Zhi. 2009 Feb;26(1):50-4.
This study sought to explore the relationship between the change in ventricular electrical remodeling caused by mechano-electrical feedback and the expression of L-type Ca2+ -channel and/or sarcoplasmic reticulum Ca2+ -ATPase in the rabbits with congestive heart failure (CHF). 138 rabbits were divided into two groups (CHF and control). We measured the ventricular monophasic action potential duration (MAPD) and ventricular effective refractory period (VERP) during ventricular pacing at the stimulus frequency of 220/240/260 bpm in these rabbits. Rapid atrial pacing (260/min) was given for 30 minutes. The MAPD and VERP were measured again. Then ventricular fibrillation was induced by S1S2S3 program stimulation. We extracted the total RNA from the myocardium respectively and detected L-type Ca2+ -channel mRNA and sarcoplasmic reticulum Ca2+ -ATPase mRNA by use of Reverse Transcriptase-Polymerase Chain Reaction (RT-PCR). In group CHF, with the increasing of preload/afterload, L-type Ca2+ -channel mRNA was up regulated after rapid atrial pacing when compared with that in control groups (P < 0.05). There was no significant change in sarcoplasmic reticulum Ca2+ -ATPase mRNA after rapid atrial pacing when compared with controls (P > or = 0.05). The changes in MAPD90 and VERP were related with the extent of L-type Ca2+ -channel mRNA up regulation. But the changes in MAPD90 and VERP were not significantly related with the extent of sarcoplasmic reticulum Ca2+ -ATPase mRNA up regulation. These findings suggest that Mechano-Electrical Feedback could increase the regional changes of ventricular electrical remodeling in rabbits with CHF and so to predispose them to ventricular arrhythmia. The changes may be related with the up regulation of L-type Ca2+ -channel mRNA, but not with sarcoplasmic reticulum Ca2+ -ATPase mRNA.
本研究旨在探讨机械电反馈引起的心室电重构变化与充血性心力衰竭（CHF）家兔L型钙通道和/或肌浆网钙ATP酶表达之间的关系。138只家兔分为两组（CHF组和对照组）。我们在这些家兔以220/240/260次/分钟的刺激频率进行心室起搏时测量心室单相动作电位时程（MAPD）和心室有效不应期（VERP）。给予快速心房起搏（260次/分钟）30分钟。再次测量MAPD和VERP。然后通过S1S2S3程序刺激诱发心室颤动。我们分别从心肌中提取总RNA，并使用逆转录聚合酶链反应（RT-PCR）检测L型钙通道mRNA和肌浆网钙ATP酶mRNA。在CHF组中，随着前负荷/后负荷的增加，快速心房起搏后L型钙通道mRNA与对照组相比上调（P<0.05）。快速心房起搏后肌浆网钙ATP酶mRNA与对照组相比无显著变化（P≥0.05）。MAPD90和VERP的变化与L型钙通道mRNA上调程度相关。但MAPD90和VERP的变化与肌浆网钙ATP酶mRNA上调程度无显著相关。这些发现提示，机械电反馈可增加CHF家兔心室电重构的局部变化，从而使其易发生室性心律失常。这些变化可能与L型钙通道mRNA上调有关，而与肌浆网钙ATP酶mRNA无关。
