[Research of L-type Ca2+ channel current in atrial myocytes of patients with chronic atrial fibrillation].
OBJECTIVE
To investigate the changes of L-type Ca(2+) channel current (I(Ca-L)) and its voltage-dependent activation and inactivation in atrial myocytes of patients with atrial fibrillation (AF).


METHODS
The specimens of right atrial appendage were obtained from 18 patients with normal sinus rhythm (NSR) and 12 patients with chronic atrial fibrillation (CAF). Single myocytes were isolated by enzymatic dissociation with two-step method and the ionic currents were recorded using whole-cell patch clamp techniques to detect the changes of I(Ca-L) density and kinetic properties.


RESULTS
(1) I(Ca-L) density was (-1.32 +/- 0.19) pA/pF in CAF group (n = 12) and (-4.58 +/- 0.39) pA/pF in NSR group (n = 21) at the test potential from -40 mV to 0 mV. I(Ca-L) density of CAF group was significantly reduced (P < 0.01), compared with the NSR group. (2) No significant differences were noted between the two groups in the voltage-dependent activation parameters (V(1/2), K) and inactivation parameters (V(1/2), K).


CONCLUSIONS
I(Ca-L) density of CAF group was significantly decreased whereas it's voltage-dependent kinetic properties had no change. This phenomenon may be one of the mechanisms of atrial electrophysiological remodeling in chronic atrial fibrillation.
Li
Miao-ling
ML
Department of Myocardial Electrophysiology, Institute of Cardiovascular Research, Luzhou Medical College, Luzhou 646000, China.
Zeng
Xiao-rong
XR
Yang
Yan
Y
Liu
Zhi-fei
ZF
Zhou
Wen
W
Ding
Yin-yuan
YY
Pei
Jie
J
D001281:Atrial Fibrillation / Q000378:metabolism / Q000503:physiopathology*; D020746:Calcium Channels, L-Type / Q000502:physiology*; D005260:Female; D006325:Heart Atria; D006801:Humans; D008297:Male; D032383:Myocytes, Cardiac / Q000378:metabolism / Q000502:physiology*; D018408:Patch-Clamp Techniques
D020746:Calcium Channels, L-Type