unidirectional block

u·ni·di·rec·tion·al block

block that prevents passage of an impulse when it approaches from one direction but not from the other, as when block in the AV node prevents anterograde conduction to the ventricles whereas retrograde conduction to the atria remains intact.

unidirectional block

[-direk′shənəl]
Etymology: L, unus + dirigere, to direct; Fr, bloc
a pathological failure of cardiac impulse conduction in one direction while conduction is possible in the opposite direction.
References in periodicals archive ?
1)" Their final conclusion stated, "The application of the concept of supernormal conduction in conjunction with that of concealed conduction and of unidirectional block permits a satisfactory interpretation of some otherwise inexplicable features of AV block encountered in clinical electrocardiography .
Thus, conditions requisite for reentry are present: dual pathways, slowing and asynchrony of conduction, unidirectional block, and recovery of excitability.

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