Impaired rotational mechanics and strain revealing subclinical left ventricular dysfunction in children with neuromuscolar disorders: a speckle tracking study

Background:Neuromuscolar disorders (NMD) progressively involvecardiovascularsystem over time. Overt heart failure usuallymanifests in the seconddecade, while younger children showapparently normal cardiac function.We aimed to identify early subclinical left ventricular (LV)dysfunctionin children affectedbyDuchenneMuscolar Distrophy (DMD)and Becker Muscolar Distrophy (BMD), evaluating myocardial strain and rotational patterns. Methods:Weanalyzed, through anEchopac(GE, Vivid 7) workstation, echocardiographic recordings from 28 asymptomatic children with NMD (22 DMD, 10+3 yrs and 6 BMD, 11+2.8 yrs), with normal LV function (ejection fraction (EF) .50%). Beyond conventional echocardiographic parameters, LV longitudinal (LS) and circumferential strain (CS) as well as rotations, twist and untwisting rate were evaluated. Results: were compared to those collected from 22 age-matched healthy children. Results: LVEF was within the normal range in our population (61+5% and 59+4%, respectively in DMD and BMD patients), although lower than in normal controls (69+4%, p=0.012 and p=0.020; vs. DMD and BMD, respectively). Results from LV strain and rotations analysis are detailed in the table. Conclusions: Global myocardial deformation is impaired in children withNMD, despite a normal EF. Furthermore, different changes in regional rotational patterns can be identified in DMD and BMD patients: a significant impairment of basal rotation is identified in DMD patients, likely an expression of inferior and lateral wall dysfunction, whereas prevalent alteration of apical rotation, twist and untwisting is observed in BMD group, which might reflect a far more widespread myocardial damage. Evidence of subtle impairment of LV function could be useful to guide patient-tailored cardio-protective therapy, in order to delay progression of the disease.