afterdepolarization


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afterdepolarization

 [af″ter-de-po″lah-rĭ-za´shun]
an oscillation in membrane potential that is dependent upon a preceding action potential for its initiation, and which upon reaching threshold potential can induce arrhythmias that are said to be “triggered.” Early afterdepolarizations occur during phases 2 and 3 of repolarization; delayed afterdepolarizations follow full repolarization.

afterdepolarization

/af·ter·de·po·lar·iza·tion/ (af″ter-de-po″lar-ĭ-za´shun) a depolarizing afterpotential, frequently one of a series, sometimes occurring in tissues not normally excitable. It may occur before (early a.) or after (delayed a.) full repolarization.

afterdepolarization

[-dēpō′lərizā′shən]
a membrane potential depolarization that follows an action potential. In cardiac muscles, it may be early (during phases 2 and 3 of the action potential) or delayed (during phase 4), and it is thought to cause atrial and ventricular tachycardia, especially in the setting of a long Q-T interval or digitalis poisoning. Also called afterpotential.

afterdepolarization

in myocardial activity a polarization, sufficient to trigger a cardiac cycle, which results from a preceding impulse or series of impulses.
References in periodicals archive ?
Hence, the beneficial effect of intravenous magnesium therapy in TdP may be suppression of transient currents that cause afterdepolarization (13).
Afterdepolarizations as a mechanism for the long QT syndrome: electrophysiologic studies of a case.
Ventricular hypertrophy amplifies transmural repolarization dispersion and induces early afterdepolarization.
Ni ions have been reported to induce vasoconstriction and early afterdepolarization in isolated rat heart and canine coronary artery by enhancing [Ca.
Single and multiple early afterdepolarization caused by nickel in rat atrial muscle.
2+] currents, and maximum diastolic potential, leading to the development of early afterdepolarization (EAD) and arrhythmias.