Patterns of late gadolinium enhancement in Duchenne muscular dystrophy carriers

Abstract

Background: This study was designed to assess whether cardiovascular magnetic resonance imaging (CMR) in Duchenne muscular dystrophy carriers (DMDc) may index any cell milieu elements of LV dysfunction and whether this cardiac phenotype may be related to genotype. The null hypothesis was that myocardial fibrosis, assessed by late gadolinium enhancement (LGE), might be similarly accounted for in DMDc and gender and age-matched controls.

Methods: Thirty DMDc patients had CMR and genotyping with 37 gender and age-matched controls. Systolic and diastolic LV function was assessed by 2D-echocardiography.

Results: Absolute and percent LGE were higher in muscular symptomatic (sym) than asymptomatic (asy) DMDc (1.77 ± 0.27 vs 0.76 ± 0.17 ml; F = 19.6, p < 0.0001 and 1.86 ± 0.26% vs 0.68 ± 0.17%, F = 22.1, p < 0.0001, respectively). There was no correlation between LGE and age. LGE was seen most frequently in segments 5 and 6; segment 5 was involved in all asy-DMDc. Subepicardial LGE predominated, compared to the mid-myocardial one (11 out of 14 DMDc). LGE was absent in the subendocardium. No correlations were seen between genotyping (type of mutation, gene region and protein domain), confined to the exon's study, and cardiac phenotype.

Conclusions: A typical myocardial LGE-pattern location (LV segments 5 and 6) was a common finding in DMDc. LGE was more frequently subepicardial plus midmyocardial in sym-DMDc, with normal LV systolic and diastolic function. No genotype-phenothype correlation was found.

Figure 1

Myocardial LGE findings in asymptomatic DMDc. CMR short-axis image of asymptomatic Duchenne carrier (ID 5, 32-year old). Myocardial LGE was only subepicardial and confined to the segments 5 and 6 of the inferolateral left ventricular wall.

Figure 2

Midwall fibrosis in asymptomatic DMDc. CMR short-axis plane of asymptomatic Duchenne carrier (ID 6, 30-year old), representing the midwall fibrosis of the inferolateral left ventricular wall. Both presented patients (ID 5 and ID 6) had normal left ventricular function, without regional hypokinesia in all the segments LGE-positive.