Evaluation of Left-Sided Heart Chambers With Novel Echocardiographic Techniques in Men With Duchenne or Becker Muscular Dystrophy

Early assessment of cardiomyopathy in Duchenne patients by means of longitudinal strain echocardiography

INTRODUCTION

The diagnosis of Duchenne-linked cardiomyopathy may be challenging. Conventional echocardiographic measurements typically show deterioration beyond the second decade. Global longitudinal strain has been proposed as an earlier marker than left ventricular ejection fraction.

MATERIAL AND METHODS

A prospective, observational, cross-sectional, case-control study was carried out. Both Duchenne patients and control subjects underwent transthoracic echocardiogram in order to assess left ventricle function. Bayesian linear regression was the main tool for inference. Age effects were parameterised by means of a spline function because of its simplicity to characterise continuous variables and smooth contributions. The posterior distribution of the marginal age effects was used to assess the earliest age of deterioration of each marker.

RESULTS

Sixteen Duchenne patients and twenty-two healthy male subjects were enrolled. On overage, cardiac function measures were found for ejection fraction and longitudinal strain among different groups. Age effects on global longitudinal strain are more reliably found at ages of 6 and above, while ejection fraction starts to deteriorate at an older age. Progressive left ventricular dysfunction in Duchenne patients is one of the key issues and starts at an early age with subtle symptoms.

CONCLUSION

This cross-sectional study provides supporting evidence that global longitudinal strain is an earlier marker of disease progression than ejection fraction in Duchenne patients.

Evaluation of Cardiac, Autonomic Functions in Ambulant Patients with Duchenne Muscular Dystrophy

Duchenne muscular dystrophy (DMD) is an X-linked genetic disorder caused by dystrophin gene mutation resulting in muscle weakness, motor delays, difficulty in standing, and inability to walk by 12 years. As disease progresses, it leads to cardiac and respiratory failure. Evaluation of cardiac autonomic status and echocardiography in DMD patients at a young age can be a potential biomarker to assess disease progression. This study aimed to investigate the younger DMD population of 5-11years of age with mild to moderate cardiac involvement for early detection using non-invasive and cost-effective tools. Genetically confirmed male DMD patients, aged 5-11 years (n = 47), screened from the outpatient department of a tertiary neuroscience institution were subjected to heart rate variability and echocardiographic analysis, and values were correlated with their clinical variables. DMD patients showed a significantly higher difference in HR, interventricular septum, E m/s, and E-wave to A-wave (E/A) ratio than normal values (p < 0.001). Significantly higher HR indicates initial sinus tachycardia and decreased IVD (d), and increased E m/s and E/A ratio mark the onset of cardiac symptoms in DMD patients even though its chamber dimension remains normal and are associated with cardiac muscle fibrosis.

Value of Global Longitudinal Strain for Identification and Monitoring of Left Ventricular Dysfunction in Becker Muscular Dystrophy

Cardiac involvement is the main cause of death in Becker muscular dystrophy (BMD). Identification of left ventricular (LV) function is crucial, but standard echocardiographic measurements such as LV ejection fraction (LVEF) might not be sensitive enough to detect early myocardial dysfunction. We explored the value of LV global longitudinal strain (GLS) as a more accurate echocardiographic parameter to detect and monitor LV dysfunction in BMD. Furthermore, we studied possible factors associated with LV dysfunction and progression. A total of 40 patients with BMD (age 39.0 ± 13.2 years) and 21 matched controls were included. Clinical variables, pulmonary tests, serum biomarkers, and echocardiograms were collected at baseline and after 2 years. LV systolic function was assessed by LVEF and LV GLS; a significant progression in LV dysfunction was defined as an absolute LV GLS deterioration ≥15%. Responsiveness to cardiac disease progression was determined using standardized response means. Patients showed impaired LVEF and LV GLS compared with controls (p <0.001). Of interest, 31 patients (77.5%) showed impaired LV GLS (defined as greater than -18%), whereas only 24 patients (60%) had reduced LVEF. LV GLS and LVEF correlated with troponin I (ρ = 0.553 and -0.523) and N-terminal pro-b-type natriuretic peptide (ρ = 0.506 and -0.585), but not with skeletal muscle or pulmonary function. At follow-up (2.0 ± 0.5 years, n = 29), LV GLS worsened significantly (-1.3 ± 0.8%, p = 0.002, standardized response mean = 0.70, annually = 0.60%), whereas LVEF remained stable. No risk factors for LV dysfunction progression were identified. In BMD, LV GLS is frequently impaired and shows deterioration over time compared with LVEF. LV GLS could be used as a more sensitive parameter to identify and monitor LV dysfunction.

Duchenne Dilated Cardiomyopathy: Cardiac Management from Prevention to Advanced Cardiovascular Therapies

Duchenne muscular dystrophy (DMD) cardiomyopathy (DCM) is characterized by a hypokinetic, dilated phenotype progressively increasing with age. Regular cardiac care is crucial in DMD care. Early recognition and prophylactic use of angiotensin converting enzyme inhibitors (ACEi) are the main stay therapeutic strategy to delay incidence of DMD-DCM. Pharmacological treatment to improve symptoms and left ventricle (LV) systolic function, have been widely implemented in the past years. Because of lack of DMD specific drugs, actual indications for established DCM include current treatment for heart failure (HF). This review focuses on current HF strategies to identify, characterize, and treat DMD-DCM.