The relation between early myocardial dysfunction and structural alterations remains unknown. Ultrasonic tissue characterization with calibrated integrated backscatter enables the evaluation of myocardial structural alterations in HCM patients, identifying the presence of myocardial disarray and diffuse myocardial fibrosis. In addition, myocardial strain assessment based on two-dimensional speckle Enzalutamide 915087-33-1 tracking analysis is a novel echocardiographic approach for a sensitive and angle-independent evaluation of myocardial global and regional systolic dysfunction. The aim of this study was therefore to assess global and regional myocardial structural alterations and systolic dysfunction in HCM mutation carriers without overt phenotype. The results of the current study demonstrated that calibrated IBS and 2D speckle tracking derived strain are able to detect myocardial regional structural and functional abnormalities in HCM mutation carriers without phenotype expression. In particular, the combined measure of basal anteroseptal calibrated IBS and longitudinal strain provided a highly sensitive index to distinguish mutation carriers from normal controls. In addition, ultrasonic techniques are sensitive to anisotropic myocardial architecture, such as myocardial disarray, which characterizes the myocardium of HCM patients. Mizuno and colleagues showed that calibrated IBS significantly correlated with the degree of myocardial disarray and interstitial fibrosis assessed by endomyocardial biopsy in HCM patients. Although the specificity may be lower than delayed-enhancement MRI, calibrated IBS might provide a more sensitive technique to assess subtle myocardial structural alterations in HCM mutation carriers. ] In addition, a report by Germans et al. has demonstrated using MRI that 81% of mutation carriers had crypts located in the basal and mid septum up to the subepicardium region. Similarly, a recent report using also MRI showed that hypertrophy usually involves the LV with a segmental rather than global pattern, with the basal anterior free wall and ventricular septum being the most frequently affected. Segmental subtle functional and structural alterations in mutation carriers may therefore anticipate the development of hypertrophy in the same LV region, while global LV function remains normal. In vitro studies have in fact demonstrated that sarcomere protein mutations are associated with impaired myocardial contractility, supporting the hypothesis that subtle myocardial dysfunction precedes and promotes the development of hypertrophy. However, further longitudinal studies are needed to describe the sequential phenotypic changes of HCM patients. Influenza A viruses possess an RNA genome consisting of eight single-stranded gene segments, each encoding at least one viral protein. In the virus particle, individual segments are assembled into ribonucleoprotein complexes that contain viral RNA encapsidated by nucleoprotein and an associated RNA-dependent RNA polymerase. As a heterocomplex, the polymerase consists of three virus encoded polypeptides: polymerase basic protein 1, polymerase basic protein 2, and polymerase acidic protein. Upon infection, the viral RNPs migrate into the host cell nucleus where negative-sense vRNA serves as a template for synthesis of positive-sense messenger RNA and complementary RNA through the mechanisms of transcription and replication, respectively. Initiation of viral transcription requires 59-cap primers generated.