PMID: 15232496Jul 3, 2004Paper

Atrial-selective antiarrhythmic actions of novel Ikur vs. Ikr, Iks, and IKAch class Ic drugs and beta blockers in pigs

Medical Science Monitor : International Medical Journal of Experimental and Clinical Research
Karsten KnoblochKlaus J Wirth

Abstract

The Kv1.5 channel, underlying IKur, is supposed to be atrial selective in pigs and humans. We investigated the effects of different potassium channel blockers, i.e. the IKur blockers AVE 0118, S9947 and S20951, with amiodarone (AM), dofetilide (DO), azimilide (AZ), ibutilide (IB), the IKs blocker HMR 1556, atropine (ATR), flecainide (FL), propafenone (PR), d,l-sotalol (SO), atenolol (ATE), and esmolol (ES), on the left and right atrial and ventricular refractoriness and left atrial vulnerability (LAV) in vivo in pigs. In pentobarbital-anesthetized pigs (n=81), atrial and ventricular effective refractory periods (ERPs) were measured with the S1-S2-extrastimulus-method and QTc time from electrocardiograms. LAV was assessed after S2-extrastimulus to the left atrium. All IKur blockers prolonged left stronger than right atrial ERP and did not change QTc. All IKr blockers predominantly prolonged the right vs. left atria. AM prolonged both atria equally, and ATR the left only. Pure beta blockers acted predominantly on the left atrium, as did FL and PR, while d,l-sotalol acted predominantly on the right. AVE 0118, S9947, S20951, ibutilide, and d,l-sotalol significantly decreased LAV (-100%, -100%, -82%, -53%, -42%; p<0.05), in contrast...Continue Reading

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