132 | Chapter 7 Figure 2. Reported early findings in relatives of DCM patients The findings with echocardiographic deformation imaging that are reported in relatives of DCM patients are reduced GLS, regional postsystolic shortening and reduced LA strain. DCM, dilated cardiomyopathy; GLS, global longitudinal strain; LA, left atrium/atrial; PLN, phospholamban. Paldino et al.50 investigated atrial strain and showed impaired peak atrial longitudinal strain in 18% of the genotype-positive relatives of DCM patients, which possibly reflects early diastolic dysfunction (Figure 2). However, the additional value of this parameter on top of GLS has not been studied. Hypertrophic cardiomyopathy Most studies in HCM classified relatives as phenotype-negative when LV wall thickness was <12 or 13 mm (Table 2). Nine studies evaluated GLS, of which seven found no difference between genotype-positive relatives and controls. Haland et al.25 observed reduced GLS in relatives without hypertrophy compared to healthy controls. In contrast, van Velzen et al.24 reported higher GLS in relatives compared to controls, which was not associated with development of HCM during 5.6 ± 2.9 years of follow-up. The cause of these contradicting results remains speculative and may be explained by the continuum of HCM disease rather than the binary affected-not affected; the relatives could have been in different stages of disease when examined. Moreover, the considerable heterogeneity in HCM phenotypes may also have
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