Screening for cardiomyopathy in muscular dystrophy with tissue doppler imaging

To study role of Tissue Doppler imaging (TDI) in identification of cardiomyopathy before development of ventricular dysfunction.

Twenty-five patients with Duchenne's (DMD) and 10 with Becker's (BMD) muscular dystrophy along with 20 controls were evaluated using TDI.

Pulse Tissue Doppler signals of the lateral left ventricle wall (lateral mitral annulus) revealed reduced systolic velocities in the DMD patients (mean +/- SD: 7.8 +/- 1.1 cm/sec vs. 8.6 +/- 1.1 cm/sec in controls) in patients of DMD. 60% of the non ambulatory DMD (ejection fraction 45+/-9%) patients had mild LV dysfunction and reduced systolic velocities (6.96 +/- 1.7 cm/sec, p<0.05 vs controls). The ambulatory DMD patients also had reduced systolic velocities (7.8 +/- 1.1 cm/sec) though ejection fraction was normal. Reduced tissue Doppler systolic velocities in the ambulatory DMD patients with normal conventional echocardiography would suggest that perhaps some of these patients (20% had velocities less than Mean - 2 SD of controls) have early myocardial dysfunction (picked up only as abnormal myocardial velocities).

TDI picked up systolic dysfunction of the lateral wall in DMD even when overall LV function was normal conventional echocardiography. Tissue Doppler imaging is a useful technique to pick up early ventricular dysfunction and should be evaluated in larger studies and also with other techniques like magnetic resonance imaging.