To evaluate if morphological or functional abnormalities could be detected with echocardiography in hypertrophic myocardiopathy (HCM) mutation carriers without left ventricle (LV) hypertrophy has developed. HCM is caused by extensive genes mutations found in two-third of patients. Because screening for carriership of a large population is unreasonable, identification of asymptomatic subjects is confined to the use of imaging such as echocardiography, by which subtle abnormalities can be detected. Comprehensive echocardiographic studies including morphological and functional assessment were performed. Asymptomatic HCM mutation carriers without hypertrophy (Phe-/Gen+, n = 14), and HCM patients (Phe+/Gen+, n = 17) were compared with healthy control subjects (n = 32) in a prospective design. Compared to controls, septum thickness was significantly higher with an elongated mitral valve in both groups. Thickened LV muscular band (LVMB) are more likely found in Phe-/Gen+ and Phe+/Gen+. The thickness of LVMB was higher in the Phe-/Gen+ versus controls. A LVMB thickness ≥3.6 mm was associated with HCM mutation carriership (sensitivity: 76.9 %, specificity: 94.1 %). The regional strain was significantly impaired in the basal segments of the septum in the Phe-/Gen+. The GLS was significantly impaired in the Phe+/Gen+ (-16.4 % ± 2.9 vs. -21.4 % ± 2.3 in control subjects, p = 0.01). Mitral A wave velocity, septal E/e', averaged E/e' were increased in both groups. E/A ratio was significantly lower in Phe+/Gen+. Morphological and functional abnormalities in hypertrophy-free HCM mutation carriers could be detected with echocardiography. Anomalous thickened LVMB could be representing a morphological marker for the HCM disease without overt hypertrophy has developed or in patients with an ambiguous diagnosis.
Keywords: Echocardiogaphy; Genetics; Hypertrophic cardiomyopathy; Hypertrophy; Morphology; Myocardial function.