Abstract 13876: Cardiovascular Magnetic Resonance Imaging Elucidates Genotype-Phenotype Relationships in Patients with Hypertrophic Cardiomyopathy
Objectives: The purpose is to determine whether cardiovascular magnetic resonance (CMR) can characterize genotype-phenotype relationships in hypertrophic cardiomyopathy (HCM).
Background: CMR is the gold standard for quantifying left ventricular mass (LVM) and demonstrating late gadolinium enhancement (LGE) and may help characterize genotype-phenotype relationships in HCM.
Methods: 100 HCM patients (mean age: 55 ± 14 yrs) who underwent CMR with gadolinium contrast were enrolled. 56% completed genetic testing. LVM and LGE were measured. Patients were stratified into 4 groups (negative genetic test with normal LV mass (G-/LVM-), negative genetic test with abnormal LV mass (G-/LVM+), positive genetic test with normal LV mass (G+/LVM-), and positive genetic test with abnormal LV mass (G+/LVM+)) and followed for cardiovascular events (CVE = Progression of NYHA, Unplanned Cardiovascular Hospitalization, Appropriate ICD Firing, Sustained VT, SCD and CV Death). Clinical follow-up was over a period of 23 ± 12 months.
Results: 46% (n = 26) who completed genetic testing had a positive test. For G+/LVM+ patients, 9 out of 15 (60%) had LGE. In comparison to those without LGE, these 9 patients had smaller left ventricular stroke volume indexed for BSA (42.1 ± 13.5 ml/m2 vs. 56.8 ± 4.3 ml/m2, p = 0.025); lower frequency of zero risk factors for SCD (n = 0, 0% vs. n = 4, 66.7%, p = 0.011); and higher frequency of ≥ 2 risk factors for sudden cardiac death (n = 5, 55.6% vs. n = 0, 0%, p = 0.011) without any difference in CVE. Subset analysis revealed MYBPC3 mutation (n=8) was associated with a lower LVEF (65.1 ± 13.1% vs. 72.6 ± 9.0%, p = 0.046) without increased CVE. Overall, 53 patients (53%) had LGE which was associated with reverse curvature (37.7% in LGE+ vs. 10.6% in LGE-, p = 0.002) and higher frequency of ≥ 2 risk factors for sudden cardiac death (n = 18, 34% vs. n = 7, 15%, p = 0.028), without increased CVE. All of these relationships remained significant after multivariate analysis.
Conclusions: LGE was associated with high-risk features, particularly in G+/LM+ subjects, and MYBPC3 was associated with decreased LVEF. CMR was successful in characterizing genotype-phenotype relationships in HCM.
- © 2011 by American Heart Association, Inc.