Cardiovascular magnetic resonance in neuromuscular disorders: looking ahead

Abstract Funding Acknowledgements Type of funding sources: None. Background Neuromuscular disorders (NMD) have a wide range of different cardiac presentations. Cardiac magnetic resonance (CMR) has an established role in diagnosis and risk stratification. We sought to access how CMR performs in predicting events in a real cohort of NMD patients (pts). Methods We included consecutive pts followed in a tertiary clinical center with NMD from January 2012 to December 2018. Clinical and CMR data were collected. During follow-up (FUP), we considered major adverse cardiovascular events (MACE) as a composite of device implantation, ventricular tachycardia/appropriate shock therapy and death. Results A total of 65 patients (pts) were included, 33 (51%) women, with mean age of 32 ± 16 years. Most patients had myotonic dystrophy (34, 52%), followed by limb–girdle muscular dystrophy (22; 34%); the remained 9 (13%) had other NMD. About half had inferior limbs predominantly affected and 74% had none, mild or moderate functional impairment. Regarding cardiac manifestations, 18% had cardiac symptoms, 97% were in sinus rhythm, median PR and QRS duration were 169 (IQR 47) ms and 101 (IQR 11) ms, respectively; median BNP was 26 (IQR 25) mg/dl. Regarding CMR, 43,3% of pts had ≥ one abnormality. Six pts had left ventricle dilation and 7 had left ventricle ejection fraction (LVEF) 55%. Three pts had significant hypertrophy (>12 mm) and there were isolated cases of hypertrabeculation, segmental alterations or right ventricle dilation. Regarding tissue characterization, 2 pts had T2 hyperintensity, 8 had early gadolinium enhancement (EGE) and 22 had late gadolinium enhancement (LGE). LGE was located mainly intramyocardium (45%) or subepicardial (36%) and the most affected segments were basal and medium inferolateral (40%). During a median FUP of 77 (IQR 33) months there were 7 deaths, 8 implanted devices (4 pacemakers and 4 CRT-D, 3 in primary prevention) and one sustained ventricular tachycardia in holter; there were no shock therapies. Table 1 describes some CMR parameters according to the occurrence of events. Using Kaplan Meier curves, there were associations between LVEF<55% and presence of LGE with occurrence of allevents (log rank test, p = 0,002 and p = 0,045, respectively), but no association were found with age, LGE pattern nor number/distribution of affected segments. Using Cox Regression, we found that the LVEF<55% was associated with 6 fold higher risk of events (HR crude 6,15; 95% CI 1,65–22,93), that remained significant after adjusting for LGE (HR adjusted 4,81, 95% CI 1,07–15,9). Conclusion In our cohort, CMR LVEF<55% and the presence of LGE were significantly associated with events during FUP, reinforcing the role of this technique on risk stratification of NMD populations