Search results
Results from the WOW.Com Content Network
Repolarization is a stage of an action potential in which the cell experiences a decrease of voltage due to the efflux of potassium (K +) ions along its electrochemical gradient. This phase occurs after the cell reaches its highest voltage from depolarization.
Depolarization is caused by the influx of sodium (Na+) ions into the heart cells, making the inside of the cells more positive and triggering contraction. Repolarization occurs when potassium (K+) ions leave the cells, restoring the negative charge and allowing the heart muscle to relax.
Benign early repolarisation (BER) is a usually benign ECG pattern producing widespread ST segment elevation that is commonly seen in young, healthy patients < 50 years of age. Also known as “high take-off” or “J-point elevation”, it may mimic pericarditis or acute MI.
Repolarization defines the resetting of the electrochemical gradients of the cell to prepare for a new action potential. The action potential (AP) of the working myocardium lasts for several hundreds of milliseconds, with the delayed repolarization securing a refractory state for new excitations throughout the entire contraction phase.
A neuronal action potential has three main stages: depolarization, repolarization, and hyperpolarization. The initial depolarization is determined by the cell’s threshold voltage, the membrane potential at which voltage-gated sodium channels (Nav) open to allow an influx of sodium ions.
The repolarization or falling phase is caused by the slow closing of sodium channels and the opening of voltage-gated potassium channels. As a result, the membrane permeability to sodium declines to resting levels.
An action potential is caused by either threshold or suprathreshold stimuli upon a neuron. It consists of three phases: depolarization, overshoot, and repolarization. An action potential propagates along the cell membrane of an axon until it reaches the terminal button.
This is called repolarization, meaning that the membrane voltage moves back toward the -70 mV value of the resting membrane potential. Repolarization returns the membrane potential to the -70 mV value of the resting potential, but overshoots that value.
Repolarization returns the membrane potential to the -70 mV value that indicates the resting potential, but it actually overshoots that value. Potassium ions reach equilibrium when the membrane voltage is below -70 mV, so a period of hyperpolarization occurs while the K + channels are open.
Progress in basic and clinical research of electrical heterogeneity across the ventricular wall in the past two decades has greatly advanced our understanding of the ionic and cellular basis for ventricular repolarization waves and their clinical implications.