Correlation of connexin43 expression and late ventricular potentials in nonischemic dilated cardiomyopathy.
Nonischemic dilated cardiomyopathy (DCM) is associated with a high risk of sudden cardiac death. Signal-averaged electrocardiography (SAECG) is a useful clinical tool for detecting late ventricular potentials (LP). Gap junction alterations have recently been shown to be involved in the pathogenesis of ventricular arrhythmias in DCM; however, the possible relationship between gap junctional connexin43 (C x 43) expression and SAECG has not yet been evaluated. In the present study 16 patients (47+/-13 years) with DCM who had undergone SAECG testing were evaluated. In each patient, the expression of C x 43 proteins was qualitatively and quantitatively determined using immunoconfocal microscopy and right ventricular biopsy specimens. The level of expression of C x 43 protein was defined as the proportion of tissue area occupied by C x 43 (percent tissue area) in each test area. The abundance and distribution of the C x 43 signal was assessed in relation to LP. Late ventricular potentials were positive in 5 patients (LP (+) group) and negative in 11 patients (LP (-) group). The incidence of sustained ventricular tachycardia in the LP (+) group was higher than that in the LP (-) group (80% vs 18%, p=0.04). The percent tissue area of C x 43 in the LP (+) group was significantly lower than that in the LP (-) group (p=0.02). Furthermore, C x 43 protein in the LP (+) group was distributed more heterogeneously than that in the LP (-) group (p=0.001). The heterogeneous expression of C x 43 protein may contribute to impaired ventricular conduction, which may be related to the LP detected on SAECG.
Kitamura
Hidetsuna
H
Division of Cardiovascular and Respiratory Medicine, Department of Internal Medicine, Kobe University Graduate School of Medicine, Kobe, Japan.
Yoshida
Akihiro
A
Ohnishi
Yoshio
Y
Okajima
Katsunori
K
Ishida
Akihiko
A
Galeano
Erdulfo J
EJ
Kubo
Shinya
S
Fukuzawa
Kouji
K
Takano
Takatsugu
T
Yokoyama
Mitsuhiro
M
D000328:Adult; D002311:Cardiomyopathy, Dilated / Q000235:genetics*; D018031:Connexin 43 / Q000235:genetics*; D004562:Electrocardiography; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics*; D006801:Humans; D007150:Immunohistochemistry; D008297:Male; D008875:Middle Aged; D018754:Ventricular Dysfunction / Q000235:genetics / Q000473:pathology / Q000503:physiopathology*; D016277:Ventricular Function, Left / Q000502:physiology*
D018031:Connexin 43