Gene mutation carriers without left ventricular hypertrophy exhibited significantly increased septal convexity into the left ventricle compared to healthy controls (5.0 vs 1.6 mm, p<0.0001).
Case-Control (n=72)
Blinded analysis
No
Does the presence of a pathogenic sarcomere mutation without left ventricular hypertrophy increase left ventricular septal convexity compared to healthy controls?
Abnormal septal convexity into the left ventricle is a newly identified imaging biomarker for subclinical hypertrophic cardiomyopathy in sarcomere mutation carriers.
Absolute Event Rate: 5% vs 1.6%
p-value: p=<0.0001
BACKGROUND: Sarcomeric gene mutations cause hypertrophic cardiomyopathy (HCM). In gene mutation carriers without left ventricular (LV) hypertrophy (G + LVH-), subclinical imaging biomarkers are recognized as predictors of overt HCM, consisting of anterior mitral valve leaflet elongation, myocardial crypts, hyperdynamic LV ejection fraction, and abnormal apical trabeculation. Reverse curvature of the interventricular septum (into the LV) is characteristic of overt HCM. We aimed to assess LV septal convexity in subclinical HCM. METHODS: Cardiovascular magnetic resonance was performed on 36 G + LVH- individuals (31 ± 14 years, 33 % males) with a pathogenic sarcomere mutation, and 36 sex and age-matched healthy controls (33 ± 12 years, 33 % males). Septal convexity (SCx) was measured in the apical four chamber view perpendicular to a reference line connecting the mid-septal wall at tricuspid valve insertion level and the apical right ventricular insertion point. RESULTS: Septal convexity was increased in G + LVH- compared to controls (maximal distance of endocardium to reference line: 5.0 ± 2.5 mm vs. 1.6 ± 2.4 mm, p ≤ 0.0001). Expected findings occurred in G + LVH- individuals: longer anterior mitral valve leaflet (23.5 ± 3.0 mm vs. 19.9 ± 3.1 mm, p ≤ 0.0001), higher relative wall thickness (0.31 ± 0.05 vs. 0.29 ± 0.04, p ≤ 0.05), higher LV ejection fraction (70.8 ± 4.3 % vs. 68.3 ± 4.4 %, p ≤ 0.05), and smaller LV end-systolic volume index (21.4 ± 4.4 ml/m(2) vs. 23.7 ± 5.8 ml/m(2), p ≤ 0.05). Other morphologic measurements (LV angles, sphericity index, and eccentricity index) were not different between G + LVH- and controls. CONCLUSIONS: Septal convexity is an additional previously undescribed feature of subclinical HCM.
Réant et al. (Thu,) conducted a case-control in Subclinical hypertrophic cardiomyopathy (n=72). Pathogenic sarcomere mutation (G+LVH-) vs. Healthy controls was evaluated on Septal convexity (SCx) into the left ventricle (p=<0.0001). Gene mutation carriers without left ventricular hypertrophy exhibited significantly increased septal convexity into the left ventricle compared to healthy controls (5.0 vs 1.6 mm, p<0.0001).
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