Genetic association of left ventricular mass assessed by M-mode and two-dimensional echocardiography

BACKGROUND: Left ventricular mass offers prognostic information for assessing cardiovascular disease risk. M-mode and two-dimensional (2D) echocardiographically-derived left ventricular mass values have shown high accuracy and reproducibility; however, no studies to date have compared left ventricular mass genetic association findings on the basis of both the methods. The aim of this study was to compare associations of single-nucleotide polymorphisms (SNPs) from genome-wide association study analyses of left ventricular mass using both methods in the same cohort. METHODS AND RESULTS: Left ventricular mass was determined using 2D and M-mode echocardiography in 711 patients (390 women); SNP genotype data were obtained using the Genome-wide Human SNP Array 6.0. Genome-wide association study analyses were performed to obtain panels of SNPs associated with left ventricular mass and left ventricular mass index. The unindexed left ventricular mass showed excellent agreement [M-mode: 170 ± 47 vs. 2D: 178 ± 56 g; intraclass correlation coefficient 0.929 (95% confidence interval 0.932, 0.909)]. The presence of left ventricular hypertrophy based on M-mode and 2D-derived left ventricular mass index values showed moderate agreement (kappa = 0.49). Eleven SNPs showed suggestive association with at least two of the four left ventricular mass traits, with one SNP in CDH13 common to all four derived traits. CONCLUSION: M-mode and 2D echocardiography left ventricular mass measurements in the same cohort identified suggestive genetic associations, both shared and unshared, suggesting common left ventricular mass biology underlying the two measures of left ventricular mass. The combined use of M-mode and 2D echo is a novel approach that may increase the yield of genetic association with left ventricular mass.