Five-year prognostic significance of global longitudinal strain in individuals with a hypertrophic cardiomyopathy gene mutation without hypertrophic changes

Background Previous studies have reported that global longitudinal strain (GLS) is reduced in patients with hypertrophic cardiomyopathy (HCM) while left ventricular ejection fraction (LVEF) is normal. Our aim was to assess GLS in individuals with HCM mutations without hypertrophic changes and to determine its prognostic value for the development of HCM. Methods and results This retrospective case-control and cohort study included 120 HCM mutation carriers and 110 controls. GLS and LVEF were assessed with Tomtec Imaging software. Age, gender, and body surface area were similar in mutation carriers and controls. Compared to controls, mutation carriers had ahigher maximal wall thickness (92 vs 8 +/- 2 mm, p<0.001), higher LVEF (60 +/- 5 vs 58 +/- 4%, p<0.001) and higher GLS (-21.4 +/- 2.3% vs -20.3 +/- 2.2%, p<0.001). The GLS difference was observed in the mid-left ventricle (-21.5 +/- 2.5% vs -19.9 +/- 2.5%, p<0.001) and the apex (-24.1 +/- 3.5% vs -22.1 +/- 3.4%, p<0.001), but not in the base of the left ventricle (-20.0 +/- 3.3% vs -20.0 +/- 2.6%, p = 0.9). Echocardiographic follow-up was performed in 80 mutation carriers. During 5.6 +/- 2.9 years' follow-up, 13 (16%) mutation carriers developed HCM. Cox regression analysis showed age (hazard ratio (HR) 1.08, p = 0.01), pathological Qwave (HR 8.56; p = 0.01), and maximal wall thickness (HR 1.94; p = 0.01) to be independent predictors of the development of HCM. GLS was not predictive of the development of HCM (HR 0.78, p = 0.07). Conclusion GLS is increased in HCM mutation carriers without hypertrophic changes. GLS was of no clear prognostic value for the development of HCM during follow-up, in contrast to age, pathological Qwaves and maximal wall thickness.