Tissue Doppler imaging detects early asymptomatic myocardial abnormalities in a dog model of Duchenne's cardiomyopathy.
OBJECTIVE
Early diagnosis of Duchenne's dilated cardiomyopathy remains a challenge for conventional echocardiography. We sought to determine whether tissue Doppler imaging (TDI) could detect early alteration in myocardial function in a dog model of Duchenne muscular dystrophy, i.e. the Golden Retriever Muscular Dystrophy (GRMD).


RESULTS
Myocardial function was assessed by TDI in 20 dogs with normal conventional parameters of systolic function (eight controls and 12 GRMD, 25+/-11 weeks) without knowledge of the genotype. M-mode TDI was recorded from a short-axis view for measurement of endocardial and epicardial velocities and myocardial velocity gradient (MVG) within the posterior wall. Controls and GRMD dogs were comparable regarding left ventricular fractional shortening (37+/-2 vs 42+/-3%, p=ns). Conversely, TDI showed, in all GRMD dogs, a dramatic decrease in systolic MVG (0.8+/-0.1 vs 2.9+/-0.3 s(-1), p<0.0001) and early diastolic MVG (2.3+/-2.2 vs 10.8+/-1.1 s(-1), p<0.0001). This MVG alteration was related to a significant decrease in endocardial velocities in GRMD whereas epicardial velocities were comparable in the two groups.


CONCLUSIONS
These results show that TDI is more sensitive than conventional echocardiography in detecting pre-clinical myocardial abnormalities before occurrence of left ventricular dilation and dysfunction. TDI should be part of the screening techniques for the early diagnosis of cardiomyopathy.
Chetboul
Valérie
V
INSERM E0001, Kremlin-Bicêtre, France. vchetboul@vet-alfort.fr
Escriou
Catherine
C
Tessier
Dominique
D
Richard
Vincent
V
Pouchelon
Jean-Louis
JL
Thibault
Hélène
H
Lallemand
Françoise
F
Thuillez
Christian
C
Blot
Stéphane
S
Derumeaux
Geneviève
G
D000818:Animals; D009202:Cardiomyopathies / Q000000981:diagnostic imaging / Q000473:pathology*; D004285:Dogs; D015150:Echocardiography, Doppler / Q000379:methods; D008297:Male; D008954:Models, Biological; D020388:Muscular Dystrophy, Duchenne / Q000000981:diagnostic imaging / Q000473:pathology*