reentrant mechanism

reentry mechanism the mechanism by which a locus of unidirectional block to conduction in cardiac muscle can result in ectopic beats or tachyarrhythmias. In addition to the block, also required are at least areas of slow conduction and refractoriness of the tissue to stimulation. Conduction of a normally initiated impulse is delayed by the block long enough for normal surrounding tissue to repolarize and to be reexcited by the delayed impulse; this may begin a self-perpetuating series of abnormal conduction cycles. See also ring model, leading circle model, and figure-of-eight model, under model, and see reentry.

Medical dictionary. 2011.

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