Editing Antiarrhythmic agent (section)

===Class I agents===
The class I antiarrhythmic agents [[Sodium channel blocker|interfere with the sodium channel]].
Class I agents are grouped by what effect they have on the Na<sup>+</sup> channel, and what effect they have on cardiac [[action potential]]s.

Class I agents are called membrane-stabilizing agents, "stabilizing" referring to the decrease of excitogenicity of the plasma membrane which is brought about by these agents. (Also noteworthy is that a few class II agents like propranolol also have a [[membrane stabilizing effect]].)

Class I agents are divided into three groups (Ia, Ib, and Ic) based upon their effect on the length of the action potential.<ref name="pmid6723689">{{cite journal |vauthors=Milne JR, Hellestrand KJ, Bexton RS, Burnett PJ, Debbas NM, Camm AJ |title=Class 1 antiarrhythmic drugs – characteristic electrocardiographic differences when assessed by atrial and ventricular pacing |journal=Eur. Heart J. |volume=5 |issue=2 |pages=99–107 |date=February 1984 |pmid=6723689 |doi= 10.1093/oxfordjournals.eurheartj.a061633}}</ref><ref name="isbn0-07-139930-5">{{cite book |author1=Trevor, Anthony J. |author2=Katzung, Bertram G. |title=Pharmacology |publisher=Lange Medical Books/McGraw-Hill, Medical Publishing Division |location=New York |year=2003 |page=43 |isbn=978-0-07-139930-2 }}</ref>
* Class Ia drugs lengthen the action potential (right shift)
* Class Ib drugs shorten the action potential (left shift)
* Class Ic drugs do not significantly affect the action potential (no shift)

<div class="skin-invert-image">
<gallery mode="packed" widths="360px" heights="160">
File:Action potential class Ia.svg|Class Ia
File:Action potential Class Ib.svg|Class Ib
File:Action potential class Ic.svg|Class Ic
</gallery>
</div>
{{clear}}