Myocardial Fibrosis in Hypertrophic Cardiomyopathy

Study Questions:

What is the relationship between myocardial scar, as measured by late gadolinium enhancement (LGE) on magnetic resonance imaging (MRI), and adverse events in patients with hypertrophic cardiomyopathy (HCM)?

Methods:

This meta-analysis evaluated the association between risk of adverse events and myocardial scar, as measured by LGE on MRI, in patients with HCM. A total of six studies including 3,067 patients were included.

Results:

Mean age was 60 years, and mean follow-up was 3.1 years. The presence of LGE was associated with increased incidence of sudden cardiac death (odds ratio [OR], 2.5; 95% confidence interval [CI], 1.4-4.4; p = 0.001), all-cause mortality (OR, 1.8; 95% CI, 1.2-2.7; p = 0.003), and cardiac death (OR, 2.8; 95% CI, 1.4-5.5; p = 0.003); there was no significant difference in heart failure death (p = 0.52). There was no evidence of publication bias, and there was no significant heterogeneity between these trials. The extent of LGE was not significantly related to sudden cardiac death (p = 0.35), all-cause mortality (p = 0.08), heart failure death, (p = 0.99), or cardiac death (p = 0.59).

Conclusions:

The authors concluded that the presence of any myocardial scar by LGE on MRI is associated with an increased risk of adverse events.

Perspective:

HCM is a common cause of sudden cardiac death particularly in younger patients, and often prompts consideration of implantable cardioverter-defibrillators. Clinical risk markers cannot precisely distinguish low- and high-risk individuals, and improved tools for risk stratification are needed. This meta-analysis demonstrates that the presence of myocardial scar by MRI can identify patients at increased risk, but more work needs to be done to determine how this imaging risk marker should be incorporated into guidelines for implantable cardioverter-defibrillator use in primary prevention of adverse events in patients with HCM.

Clinical Topics: Arrhythmias and Clinical EP, Heart Failure and Cardiomyopathies, Noninvasive Imaging, Prevention, Implantable Devices, SCD/Ventricular Arrhythmias, Acute Heart Failure, Magnetic Resonance Imaging

Keywords: Cardiomyopathy, Hypertrophic, Death, Sudden, Cardiac, Defibrillators, Implantable, Gadolinium, Heart Failure, Magnetic Resonance Imaging, Magnetic Resonance Spectroscopy, Mortality, Myocardium, Primary Prevention, Risk


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