Abstract 4139740: Left Atrial Strain and Genotype Associated with Clinical Outcomes in Genetic Hypertrophic Cardiomyopathy

Background: Genetic cardiomyopathies (CMP) are a group of inherited diseases that can lead to heart failure and sudden cardiac death. Hypertrophic CMP (HCMP) is a common genetic disorder. Despite the knowledge about the different causal genes, the relationship between individual genotypes and phenotypes is incomplete. Using the myocardial strain measurement, the relationship between individual genotypes and phenotypes could be evaluated. Methods: We consecutively enrolled 183 patients (123 males, 63 ± 19 year-old) with HCMP who underwent genetic testing. All patients were divided into three groups: gene (-) group, sarcomeric gene (+) group and non-sarcomeric gene (+) group. Echocardiographic images were reviewed and used to calculate myocardial strain. The data of clinical outcomes were obtained and analyzed according to the genotypes and myocardial strain. The primary composite end point of major cardiac adverse events (MACEs), consisting of left ventricular dysfunction (LVD) development, heart failure development, lethal arrhythmias and all-cause death, was analyzed. Results: Myocardial stains, including global LV longitudinal strain, LA strain and RV strain, were not statistically different among the groups. MACE-free survival rate in the gene (-) group was significantly lower than in other groups (log-rank p <0.001). LA conduit strain was significantly related with lethal arrhythmia. Univariable regression for LA conduit strain and lethal arrhythmias showed an odds ratio of 1.137 (95% CI, 1.008–1.283) with p =0.037. For receiver operating characteristic analysis, the areas under the curve for LA conduit strain was 0.716 ( p =0.009). An absolute LA conduit strain cutoff of 10.0% yielded a sensitivity rate of 67% and specificity rate of 66%. The lethal arrhythmias-free survival rate in the group with LA conduit strain lower than 10.0% was significantly lower than in the other group (log-rank p =0.024). Conclusion: The genotype-positive patients with HCMP have worse clinical outcomes. The LA conduit strain was related to lethal arrhythmias in HCMP.