Background: Duchenne muscular dystrophy (DMD) is the most common inherited muscle disease. The incidence of cardiomyopathy increases with age and currently represents the main death cause. Close follow-up by cardiologists and stratification of heart disease is recommended.
Objective and methods: We assessed left ventricular (LV) systolic dysfunction, in a retrospective cross-sectional study, using conventional echocardiography and LV global longitudinal strain (GLS) by speckle-tracking echocardiography. We firstly aimed to confirm the impairment of LV dysfunction related to age. Second, to describe GLS profile in teenagers and young adults with DMD followed by a cardiology outpatient unit in Brazil.
LV systolic dysfunction was defined by ejection fraction (EF) with Simpson’s method of < 52% and/or GLS < 20% (considering absolute values), both performed with GE®-Vivid E9. We first performed a descriptive analysis where continuous variables were described as mean ± SD and categorical variables as percentages. We assessed the association between both LV systolic dysfunction parameters (EF and GLS) and age (by Pearson’s correlation), and in a binary logistic regression analysis.
Results: A total of 18 patients were evaluated with a mean age of 16.4 ± 5.4 years. EF was 50 ± 9%, where 12 patients (67%) presented EF < 52%. Segmental abnormalities involving inferolateral wall were reported in 8 (44%) individuals. Mean GLS was ?15.4 ± 3.5%, where 16 patients (89%) presented GLS < 20%. In four cases (22%) GLS was reduced with preserved EF. As continuous variables, progressive reduction of EF and GLS worsening were both associated with increasing age (r = ?0.589 and 0.602, respectively). In a logistic regression, older patients (each 1-year) were associated with EF < 52% (OR 1.35, 95% CI 1.01 – 1.83).
Conclusions: In this group of young patients with DMD, LV systolic dysfunction defined by conventional or speckle-tracking echocardiography, was common with age-related worsening of measurements. In addition to traditional parameters such as EF, assessment of GLS was useful in the monitoring of myocardial involvement in DMD, including patients in early stages of LV systolic dysfunction.