Increased mid-left ventricular rotation in patients with Duchenne muscular dystrophy using two-dimensional speckle tracking echocardiography.

Abstract

In patients with Duchenne muscular dystrophy (DMD), cardiomyopathy initially occurs during adolescence. In routine echocardiographic examination, we often recognize increased rotational movement of the left ventricle in DMD patients even if their conventional echocardiographic finding is normal. Two-dimensional speckle tracking echocardiography can assess left ventricular (LV) rotation. The aim of this study was to analyze the mid-LV rotation and to investigate the clinical implication of this abnormal movement. Nineteen DMD patients (age 15.5±3.1years) and 22 age-matched healthy subjects were recruited. The two-dimensional speckle tracking method was used to determine the mid-LV rotation at the papillary muscle level. The mid-LV rotation and rotational velocity were calculated and were compared with other echocardiographic data and indices of autonomic function. Total rotation was greater in the DMD group than in the normal group (7.3±1.4° versus 5.2°±1.3°, p<0.05). Both peak diastolic clockwise and counterclockwise rotational velocity were greater in the DMD group (p<0.005 and p<0.05, respectively). Time from the second heart sound to peak diastolic clockwise rotation (% diastolic duration) was greater in the DMD group (p<0.005). Total rotation and percentage of adjacent normal R-R intervals more than 50ms different showed a negative correlation (r=-0.72) in the DMD group. In DMD patients, cases diagnosed with normal LV fractional shortening showed an increase in mid-LV rotation that might be due to relative increase of sympathetic nervous function before global cardiac function decreases.