Progression of Myocardial Fibrosis Assessed With Cardiac Magnetic Resonance in Hypertrophic Cardiomyopathy

Study Questions:

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)?

Methods:

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.

Results:

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).

Conclusions:

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.

Perspective:

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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