Background-The differential diagnosis of left ventricular (LV) hypertrophy remains challenging in clinical practice, in particular, between hypertrophic cardiomyopathy (HCM) and increased LV wall thickness because of systemic hypertension. Diffuse myocardial disease is a characteristic feature in HCM, and an early manifestation of sarcomeregene mutations in subexpressed family members (G+P− subjects). This study aimed to investigate whether detecting diffuse myocardial disease by T1 mapping can discriminate between HCM versus hypertensive heart disease as well as to detect genetically driven interstitial changes in the G+P− subjects. (HCM, n=95; hypertension, n=69) and G+P− subjects (n=23) underwent a clinical cardiovascular magnetic resonance protocol (3 tesla) for cardiac volumes, function, and scar imaging. T1 mapping was performed before and >20 minutes after administration of 0.2 mmol/kg of gadobutrol. Native T1 and extracellular volume fraction were significantly higher in HCM compared with patients with hypertension (P<0.0001), including in subgroup comparisons of HCM subjects without evidence of late gadolinium enhancement, as well as of hypertensive patients LV wall thickness of >15 mm (P<0.0001). Compared with controls, native T1 was significantly higher in G+P− subjects (P<0.0001) and 65% of G+P− subjects had a native T1 value >2 SD above the mean of the normal range. Native T1 was an independent discriminator between HCM and hypertension, over and above extracellular volume fraction, LV wall thickness and indexed LV mass. Native T1 was also useful in separating G+P− subjects from controls. Conclusions-Native T1 may be applied to discriminate between HCM and hypertensive heart disease and detect early changes in G+P− subjects. (Figure 1).
Methods and Results-Patients with diagnoses of HCM or hypertension
8-12Although T1 mapping supports detection of diffuse myocardial disease, late gadolinium enhancement (LGE) helps with visualizing regional changes, such as replacement fibrosis in phenotypically subexpressed HCM gene carriers (G+P− subjects) and overt HCM disease. In compensated LVH because of hypertension-that is before extensive structural and metabolic remodeling with cavity dilatation and functional impairment (eccentric remodeling)-findings reflect physiological adaptations with an increased cellular size because of addition of new, but functional myofibrilles in-parallel and in-series, enabling the ventricle to generate greater forces and to outweigh the increased wall stress. 11,[13][14][15][16][17] Interstitial fibrosis and the expansion of extracellular space in hypertension herald decompensation with eccentric remodeling and heart failure. [12][13][14][15][18][19][20][21][22] In this study, we investigated the ability of CMR to discern hypertrophic phenotypes based on detection of diffuse myocardial disease and regional fibrosis by myocardial T1 mapping and LGE, respectively, first, in overt LVH, and second, in phenotypically subexpressed HCM gene carriers.
MethodsConsecutive subjects en...
The results document to whom and how helpful it is to talk with others about SCD pain episodes and how SCD disclosure is related to strategies for managing this disease.
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