P439Is beta-adrenoreceptor polymorphism related to functional and echocardiographic presentation in patiehts with hypertrophic cardiomyopathy?


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Abstract

Introduction: Hypertrophic cardiomyopathy (HCM) is a genetically determined disease characterized by sarcomere mutation. However, the presentation is variable and gene polymorphisms other than etiologically related may modify the clinical presentation.Aim: The aim of this study was to define whether CEPT test results related to exercise capacity and ECHO parameters are related to beta-adrenoreceptor polymorphism in HCM patients.Methods: We studied 56 HCM patients (34 male, 22 female), aged 58 ±13, with well preserved systolic function – ejection fraction (EF)=58±7%. Beta-adrenoreceptor polymorphism was determined by means of RT-PCR reaction in 47 patients. Each sample was classified as: homozygote XX(normal), homozygote YY (with two mutated alleles) or heterozygote XY. 46 patients underwent CPET test, according to Bruce protocol. Echocardiographic examination involved standard measurements, extended diastolic function panel using tissue Doppler and advanced local function using speckle tracking ECHO analysis (longitudinal strain/strain rate from apical views, radial, circumferential strain LV rotation and twist). Single regression modeling was applied to detect relationships between functional variables, ECHO data and beta-adrenoreceptor polymorphism.Results: 11 subjects from the investigated population (11/47pts, 23%) were mutated allele carriers: 10 heterozygote XY, 1 homozygote YY. CPET exercise tolerance-related variables and echocasrdiographic variables are summarized in the table. CEPT test results and ECHO parameters were similar regardless of the presence of beta-adrenoreceptor polymorphism in HCM patients - see table. LV outflow obstruction was present in 12,5%, unrelated to ADRB1 genotype.Conclusions: Standard echocardiographic and speckle tracking derived data (including advanced LV function) as well as CPET results related to exercise capacity are independent of beta-adrenoreceptor polymorphism in HCM patients.

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