Premium
Molecular Remodeling of Kv4.3 Potassium Channels in Human Atrial Fibrillation
Author(s) -
GRAMMER JOACHIM B.,
BOSCH RALPH F.,
KÜHLKAMP VOLKER,
SEIPEL LUDGER
Publication year - 2000
Publication title -
journal of cardiovascular electrophysiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.193
H-Index - 138
eISSN - 1540-8167
pISSN - 1045-3873
DOI - 10.1111/j.1540-8167.2000.tb00024.x
Subject(s) - atrial fibrillation , potassium channel , medicine , cardiac transient outward potassium current , sinus rhythm , cardiology , gene expression , patch clamp , ion channel , endocrinology , repolarization , potassium , messenger rna , electrophysiology , gene , chemistry , receptor , biochemistry , organic chemistry
Repolarizing Potassium Currents in Atrial Fibrillation, introduction: Atrial fibrillation (AF) is associated with important alterations in cardiac ion channels that cause shortening and impaired rate adaptation of atrial repolarization. The mechanisms underlying potassium current remodeling in human AF are not clear. We investigated the effects of AF on the gene expression of the Kv4.3, Kv1.4, and Kv1.5 potassium channel subunits and correlated the findings with the transient outward (I 10 ) and the sustained outward (I sus or I kur ) potassium current. Methods and Results: Semiquantitative reverse transcription‐polymerase chain reaction was used to evaluate mRNA expression, and ion currents were studied with the patch clamp technique in right atrial appendages from patients in AF and compared with those from patients in stable sinus rhythm (SR). The presence of AF was associated with a 61% reduction in Kv4.3 mRNA expression (P < 0.001 vs SR), which was paralleled by a reduction in I to current densities in this group of patients (i.e., at ± 50 mV: 7.44 ± 0.76 pA/pF in SR and 1.24 ± 0.28 pA/pF in AF; P < 0.001 vs SR). mRNA levels of Kv 1.4 were identical in the two groups. AF did not affect either the gene expression of Kv 1.5 or the current densities of I sus . Conclusion: Chronic AF in humans reduces I to by transcriptional down‐regulation of the Kv4.3 potassium channel. Altered gene expression is an important component of the electrical remodeling process and may contribute to repolarization abnormalities in AF.