Moving in the right direction: elucidating the mechanisms of interaction between flecainide and the cardiac ryanodine receptor. (2nd December 2021)

• Record Type: Journal Article
• Authors: Bannister, Mark L.; MacLeod, Kenneth T.; George, Christopher H.
• Other Names: Lukowski Robert guestEditor.; Feil Robert guestEditor.
• Is Part Of: British journal of pharmacology. Volume 179:Number 11(2022)
• Page Start: 2558
• Page End: 2563
• Publication Date: 2021-12-02
• Subjects: anti‐arrhythmic drugs -- cardiac arrhythmias -- catecholaminergic polymorphic ventricular tachycardia -- flecainide -- mechanism -- ryanodine receptor calcium release channel; Pharmacology -- Periodicals; Chemotherapy -- Periodicals; Drug Therapy -- Periodicals; Pharmacology -- Periodicals; 615.1
• DOI: 10.1111/bph.15718
• Languages: English
• ISSNs: 0007-1188

Abstract

Abstract : Flecainide is used to treat catecholaminergic polymorphic ventricular tachycardia (CPVT), an arrhythmia caused by disrupted cellular Ca 2+ handling following β‐adrenergic stimulation. The clinical efficacy of flecainide in this context involves complex effects on multiple ion channels that may be influenced by the disease state. A compelling narrative has been constructed around flecainide's nonselective block of sarcoplasmic reticulum (SR) lumen‐to‐cytoplasm Ca 2+ release through intracellular calcium release channels (RyR2). However, ion fluxes across the SR membrane during heart contraction are bidirectional, and here, we review experimental evidence that flecainide's principal action on RyR2 involves the partial block of ion flow in the cytoplasm‐to‐lumen direction (i.e., flecainide inhibits RyR2‐mediated SR 'countercurrent'). Experimental approaches that could advance new knowledge on the mechanism of RyR2 block by flecainide are proposed. Some impediments to progress in this area, that must be overcome to enable the development of superior drugs to treat CPVT, are also considered.