Endothelin-1 gene polymorphism in the identification of patients at risk for malignant ventricular arrhythmia.
BACKGROUND
The endothelins are peptides with vasoconstricting and growth-promoting properties. Endothelin-1 (ET-1) is known for its direct positive inotropic and chronotropic effects on isolated heart, and for growth effects. The aim of this pilot study was to investigate the frequency distribution of a common polymorphism of the endothelin (ET-1) gene and its possible relation to the hemodynamic consequences of malignant ventricular arrhythmia in patients with structural heart disease.


METHODS
We studied 26 consecutive patients with malignant ventricular arrhythmia and implantable cardioverter defibrillators (ICD), mean age 62.7 +/- 12.2 years, mean LVEF 0.37 +/- 11. The Taq polymorphism of ET-1 was detected using our original PCR method. The PCR product with a length of 358 bp in its non-mutated form contains a target sequence for the TaqI restrictive enzyme, while the mutated product loses this cleavage site.


RESULTS
Out of the 26 patients, 9 (34%) had recurrent palpitations and 8 (30.8%) had syncopes during their malignant arrhythmic episodes. 19 of the patients were receiving amiodarone after ICD implantation, 7 were not. 15 patients had the (++) and 11 had the (+ -) ET-1 genotype; none had the (- -) genotype. The risk of syncopes was associated with the (++) genotype (p=0.01). Patients with amiodarone had a significantly higher frequency of the (++) genotype (p=0.011).


CONCLUSIONS
All our results suggested that the presence of the (++)ET-1 genotype in patients with structural heart disease, severe left ventricular dysfunction, and malignant ventricular arrhythmia put these patients at a higher risk of hemodynamic collapse during arrhythmic episodes.
Kozák
Milan
M
Department of Cardiology and Medicine, Masaryk University Hospital Brno, Czech Republic. kozak.milan@post.cz
Hollá
Lýdie Izákovicova
LI
Krivan
Lubomír
L
Vasků
Anna
A
Sepsi
Milan
M
Borivoj
Semrád
S
Vácha
Jirí
J
D000368:Aged; D001145:Arrhythmias, Cardiac / Q000235:genetics* / Q000473:pathology*; D019332:Endothelin-1 / Q000235:genetics*; D005260:Female; D005838:Genotype; D006439:Hemodynamics; D006579:Heterozygote; D006720:Homozygote; D006801:Humans; D008297:Male; D008875:Middle Aged; D010865:Pilot Projects; D016133:Polymerase Chain Reaction; D011110:Polymorphism, Genetic
D019332:Endothelin-1