Evidence of cardiomyopathy associated with Marfan syndrome in children.

Objective: Marfan syndrome (MFS)-associated cardiomyopathy, defined as ventricular dilation and dysfunction unexplained by volume loading, is not well defined in children. This study evaluated ventricular size and function in paediatric MFS using cardiac MRI (cMRI).

Methods: This retrospective cohort study examined patients with MFS <19 years old at first cMRI. Left ventricular (LV) ejection fraction (EF) <55% was considered abnormal, as were z-scores >2. Combined mitral and aortic regurgitation indexed to LV stroke volume <20% defined absent/mild volume load. Biventricular volumes and EF on serial cMRI studies were compared with normative paediatric cMRI values, with measures converted to z-scores as appropriate. Longitudinal changes in volumes and EF were evaluated by mixed linear regression. Associations between ventricular, aortic and mitral characteristics were evaluated.

Results: 58 patients (60% male) were evaluated. Median age at initial cMRI was 13.6 years (IQR 10.0-15.8 years). Among patients with absent/mild LV volume load at initial cMRI (n=44, 76%), indexed LV end-diastolic volume (EDV) was significantly increased above normative values (median z-score 1.8, IQR 0.6-3.5, p<0.0001) and LVEF was abnormal in 48% (21/44). In the absence of volume loading, mitral valve prolapse (MVP) was associated with larger ventricular volumes and lower LVEF. Among those with serial cMRIs, LVEF and EDV z-scores did not significantly change over a mean follow-up time between cMRI studies of 1.5 years.

Conclusion: Ventricular dilation and reduced EF are common in children with MFS and occur with no/mild LV volume load, suggesting intrinsic cardiomyopathy. MVP may be associated with cardiomyopathy.