Study design and rationale of the Visualizing Subclinical Myocardial Changes with Shear Wave Elastography in Dilated Cardiomyopathy (VISUALIZE-DCM) trial.

Cardiac fibrosis is a key disease hallmark of dilated cardiomyopathy (DCM) and is associated with a risk of malignant arrhythmias and sudden cardiac death. Fibrosis can be the earliest sign of disease in asymptomatic family members carrying pathogenic variants, making timely recognition essential. Although echocardiography is often used for family screening, conventional echocardiography cannot assess myocardial tissue characteristics such as fibrosis. Cardiac magnetic resonance imaging (CMR), the reference standard for detecting myocardial fibrosis, provides tissue characterization but is challenging to be used as a first-line screening for all at-risk family members. Shear wave elastography (SWE) using high-frame rate echocardiography is an emerging technique that enables assessment of myocardial stiffness as a surrogate for fibrosis. The VISUALIZE-DCM trial is an investigator-initiated, single-center prospective study that evaluates SWE as a triage tool for CMR to detect myocardial fibrosis, and to determine whether increased myocardial stiffness is an early feature of genetic DCM. In this study, both naturally occurring and acoustic generated shear wave speeds (SWS) are assessed using high-frame rate imaging. Natural shear waves arise during valvular closure, whereas generated shear waves are induced by the acoustic radiation force. Myocardial stiffness measurements derived from SWS will be obtained in patients with established DCM, their at-risk family members, and healthy volunteers. SWE findings will be compared with fibrosis patterns on CMR, evaluated for their ability to detect early disease development in relatives, and contrasted with reference values from healthy controls to determine their potential clinical utility in DCM screening and risk stratification.