Selina S Vickery, BS; Jerry R Mendell, MD, Kelly Lehman, APN, Kan N. Hor, MD
Background: Limb-Girdle Muscular Dystrophies (LGMD) are an inheritable group of genetic disorders primarily involving progressive weakening and atrophy of the pelvic or shoulder girdle musculature with potential cardiac dysfunction. Prior reports stratified frequency of cardiac disease based on genetic mutations. The general incidence of cardiac muscle involvement in LGMD is variable depending on genetic factors and carry important indications for clinical management. Cardiac magnetic resonance imaging (CMR) is increasingly used in dystrophinopathies and determining management. There is limited CMR data in adult LGMD patients and fewer reports in younger patients. Therefore, we sought to determine the extent of cardiac involvement based on genetic risk of cardiomyopathy.
Methods: This is a retrospective review of LGMD patients followed at our institution who underwent CMR assessment. Patients stratified into Group A (high incidence of cardiomyopathy; LGMDs 1B, 2E, 2F and 2I) and Group B (rare or no reported cardiomyopathy; LGMDs 1A, 1C, 2A, 2B, 2C, 2D, 2G, 2H, 2J) with CMR studies were assessed for presence of cardiac scar defined as late gadolinium enhancement (LGE) and LVEF for each subject.
Results: 41 subjects were identified with average age of 21.3±11.5 years (range 6-50) with normal LVEF 58±12.1% and 12/41 (29.3%) with LGE with the youngest patient age 12.4 years. Group A included 14/41 (34%) and 27/41 (66%) were in Group B. Group A had higher incidence of LGE 6/14(42.9%) with preserved LVEF of 58.2±11% compared to Group B with 6/27 (22.2%) with no difference in LVEF of 55.7±16.4% (p = 0.5). When stratified by LGE status, the LGE-positive group was older at 26.4±11.9 years and had preserved LVEF of 61.9±11.1% versus LGE-negative group of 19.1±10.9 years (p = 0.03) with abnormal LVEF of 49.4±9.5% (p =0.0008).
Conclusion: This is the largest study of CMR in LGMD patients, confirming presence of cardiac disease by LGE in the high risk group. Surprisingly, nearly 25% of the low risk mutations have evidence of LGE. Abnormal LGE predicted abnormalities in LVEF in both Group A and Group B. Management of LGMD patients should include CMR even in low risk population. Ongoing data collection may reveal disease cluster in previous low risk groups.