Diagnostic and Prognostic Value of Cardiovascular Magnetic Resonance in Neuromuscular Cardiomyopathies.

Abstract

Neuromuscular diseases (NMD) encompass a broad spectrum of diseases with variable type of cardiac involvement and there is lack of clinical data on Cardiovascular Magnetic Resonance (CMR) phenotypes or even prognostic value of CMR in NMD. We explored the diagnostic and prognostic value of CMR in NMD-related cardiomyopathies. The study included retrospective analysis of a cohort of 111 patients with various forms of NMD; mitochondrial: n = 14, Friedreich's ataxia (FA): n = 27, myotonic dystrophy: n = 27, Becker/Duchenne's muscular dystrophy (BMD/DMD): n = 15, Duchenne's carriers: n = 6, other: n = 22. Biventricular volumes and function and myocardial late gadolinium enhancement (LGE) pattern and extent were assessed by CMR. Patients were followed-up for the composite clinical endpoint of death, heart failure development or need for permanent pacemaker/intracardiac defibrillator. The major NMD subtypes, i.e. FA, mitochondrial, BMD/DMD, and myotonic dystrophy had significant differences in the incidence of LGE (56%, 21%, 62% & 30% respectively, chi2 = 9.86, p = 0.042) and type of cardiomyopathy phenotype (chi2 = 13.8, p = 0.008), extent/pattern (p = 0.006) and progression rate of LGE (p = 0.006). In survival analysis the composite clinical endpoint differed significantly between NMD subtypes (p = 0.031), while the subgroup with LGE + and LVEF < 50% had the worst prognosis (Log-rank p = 0.0034). We present data from a unique cohort of NMD patients and provide evidence on the incidence, patterns, and the prognostic value of LGE in NMD-related cardiomyopathy. LGE is variably present in NMD subtypes and correlates with LV remodelling, dysfunction, and clinical outcomes in patients with NMD.