Blayer Y, Reisin L, Manoach M
Department of Physiology, Tel Aviv Medical School, Israel.
J Basic Clin Physiol Pharmacol. 1993 Oct-Dec;4(4):281-90. doi: 10.1515/jbcpp.1993.4.4.281.
Ventricular fibrillation in humans is generally sustained (SVF), but it can be also transient (TVF), reverting spontaneously to sinus rhythm. In previous studies we have shown that: a) TVF appears in all young mammals and varies according to age and species; b) it requires synchronization of myocardial cell activity; c) infusion of certain drugs may change the type of ventricular fibrillation from sustained into transient. We hypothesize that the synchronization required for TVF depends on the electrical conductivity of intercellular structures. These intercellular couplings differ among species and decrease with age. Comparison between the inter- and intra-specific variations of intercellular connective structure described in the literature with the type of ventricular fibrillation found in our previous studies on various animals of different ages showed a clear relationship between these histological variations and the changes in the type of ventricular fibrillation. In this study we examined intercellular connective structures ultrastructurally in 3 groups of cats: a. control, untreated cats exhibiting sustained ventricular fibrillation; b. untreated cats exhibiting transient ventricular fibrillation; c. treated cats exhibiting sustained ventricular fibrillation before infusion of a defibrillating drug and transient ventricular fibrillation thereafter. It was found that the intercellular connective structure in cats exhibiting sustained ventricular fibrillation differs significantly from that in cats exhibiting transient fibrillation. In hearts exhibiting sustained ventricular fibrillation, many intercellular connective structures are widened and the degree of widening is pronounced, forming a continuous line, while in hearts exhibiting transient ventricular fibrillation the widened junctions are rare and isolated and the widening is relatively small. These preliminary results strongly support our above-mentioned hypothesis, providing an explanation for the origin of transient ventricular fibrillation and a tool for the development of new defibrillating drugs.
人类的心室颤动通常是持续性的（SVF），但也可能是短暂性的（TVF），可自发恢复为窦性心律。在之前的研究中我们已经表明：a）TVF出现在所有年轻哺乳动物中，并随年龄和物种而变化；b）它需要心肌细胞活动同步化；c）输注某些药物可能会使心室颤动的类型从持续性转变为短暂性。我们假设TVF所需的同步化取决于细胞间结构的电导率。这些细胞间连接在物种间存在差异，并随年龄增长而减少。将文献中描述的细胞间结缔组织结构的种间和种内变异与我们之前对不同年龄的各种动物进行研究时发现的心室颤动类型进行比较，结果表明这些组织学变异与心室颤动类型的变化之间存在明显的关系。在本研究中，我们对三组猫的细胞间结缔组织结构进行了超微结构检查：a. 对照组，未治疗的猫表现为持续性心室颤动；b. 未治疗的猫表现为短暂性心室颤动；c. 治疗组，猫在输注除颤药物前表现为持续性心室颤动，之后表现为短暂性心室颤动。结果发现，表现为持续性心室颤动的猫的细胞间结缔组织结构与表现为短暂性心室颤动的猫的结构有显著差异。在表现为持续性心室颤动的心脏中，许多细胞间结缔组织结构增宽，且增宽程度明显，形成一条连续的线，而在表现为短暂性心室颤动的心脏中，增宽的连接很少且孤立，增宽程度相对较小。这些初步结果有力地支持了我们上述的假设，为短暂性心室颤动的起源提供了解释，并为开发新的除颤药物提供了一种工具。
