Clinical detection of mutation carriers of hypertrophic cardiomyopathy in perspective: is cardiac imaging the crystal ball of the cardiologist?

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 a higher maximal wall thickness (9 ± 2 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 Q wave (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 Q waves and maximal wall thickness.

Electronic supplementary material

The online version of this article (10.1007/s12471-019-1226-5) contains supplementary material, which is available to authorized users.

Prognostic significance of anterior mitral valve leaflet length in individuals with a hypertrophic cardiomyopathy gene mutation without hypertrophic changes

Purpose

Previous studies suggest that anterior mitral valve leaflet (AMVL) elongation is a primary phenotypic feature in hypertrophic cardiomyopathy (HCM). Our aim was to assess AMVL length in individuals with HCM gene mutations and in healthy controls and to identify predictors of the development of HCM during follow-up.

Methods

A total of 133 HCM mutation carriers and 135 controls underwent cardiac examination including electro- and echocardiography. AMVL length was measured in the parasternal long axis and apical three chamber view during diastole. Univariate and multivariable cox proportional hazard regression analyses were performed to identify predictors of HCM.

Results

There were no significant differences between HCM mutation carriers and controls regarding age and sex. In the parasternal long axis view, AMVL length was similar in mutation carriers and controls (24 ± 4 vs 24 ± 4 mm, p = 0.8). In the apical three chamber view, AMVL were shorter in mutation carriers (29 ± 4 vs 30 ± 4 mm, p = 0.02). When averaged for both views, AMVL length was similar in mutation carriers and controls (27 ± 3 vs 27 ± 3 mm, p = 0.2). During 5.8 ± 3.0 years follow-up, 13 (14%) HCM mutation carriers developed HCM. Pathological Q wave (hazard ratio 9.89, p = 0.004), E/e′ ratio (hazard ratio 2.52, p = 0.001), and maximal wall thickness (hazard ratio 2.15, p = 0.001) were independent predictors of HCM. AMVL length was not predictive of the development of HCM.

Conclusions

AMVL length is similar in HCM mutation carriers and controls. AMVL length is not predictive of the development of HCM, in contrast to pathological Q wave, E/e′ ratio, and maximal wall thickness.