Progression of Myocardial Fibrosis Assessed With Cardiac Magnetic Resonance in Hypertrophic Cardiomyopathy
What is the relationship between progression of fibrosis, as measured by late-gadolinium enhancement (LGE) on magnetic resonance imaging (MRI), and clinical variables in patients with hypertrophic cardiomyopathy (HCM)?
The study examined 55 individuals with HCM imaged by two sequential MRI studies a mean of 719 days apart, and compared interval changes in the prevalence and mass of myocardial fibrosis, as well as the relationship between changes in mass and clinical variables.
The prevalence of LGE increased from 82% to 96% during the study. Amongst individuals with baseline LGE by MRI, there was a significant increase in LGE between the MRI studies (13.3 ± 15.2 g vs. 24.6 ± 27.5 g, p < 0.001). Further, 44 patients had an increase of ≥1 g of myocardium with LGE, with a median increase of 6 g. Among clinical variables, both an apical pattern of HCM (p = 0.001) and the baseline extent of LGE (p = 0.02) were independently associated with the increase in LGE. Finally, individuals with a worsened functional class had a higher increase in extent of LGE than those with a stable or improved functional class (p = 0.03).
This study observed that the prevalence and extent of fibrosis increased rapidly in the majority of individuals with HCM, and that those with a worsened functional status had a greater increase in LGE. Clinical variables independently associated with an increase in LGE included an apical pattern of HCM and the baseline extent of LGE.
Previous studies have demonstrated that myocardial fibrosis by LGE conveys significant prognostic implications in regards to symptoms and cardiovascular events. This study observed a markedly rapid increase in the prevalence and mass of myocardial fibrosis over a mean follow-up of only 2 years. A large majority of individuals demonstrated significant progression of fibrosis over this time, suggesting that a single MRI study may be inadequate to provide optimal risk assessment. Future studies are needed to determine whether changes in the prevalence and extent of fibrosis over time are a useful marker for patient risk.
Clinical Topics: Arrhythmias and Clinical EP, Congenital Heart Disease and Pediatric Cardiology, Heart Failure and Cardiomyopathies, Noninvasive Imaging, SCD/Ventricular Arrhythmias, Congenital Heart Disease, CHD & Pediatrics and Arrhythmias, CHD & Pediatrics and Imaging, CHD & Pediatrics and Prevention, CHD & Pediatrics and Quality Improvement, Acute Heart Failure, Magnetic Resonance Imaging
Keywords: Heart Diseases, Prevalence, Follow-Up Studies, Heart Defects, Congenital, Cardiomyopathy, Hypertrophic, Gadolinium, Heart Failure, Risk Assessment, Magnetic Resonance Spectroscopy, Fibrosis, Magnetic Resonance Imaging, Death, Sudden, Cardiac
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