Increase in endocardial rotation during doxorubicin treatment

Treatment of cardiomyopathy, when detected early, may slow myocardial deterioration and even reverse its course. However, no efficient, noninvasive measure of cardiac function is yet able to detect the early signs of cardiomyopathy. The aim of this study was to determine whether ultrasound speckle tracking analysis is a more sensitive measure of early changes of cardiac function than standard echocardiographic parameters. Eight Wistar rats were injected with doxorubicin and scanned weekly by ultrasound in order to follow the early stages of cardiomyopathy. Apical short-axis scans were analyzed by a novel speckle tracking imaging program, enabling layer-specific assessment of myocardial function. Only four of eight rats survived the full treatment. They showed a significant elevation of endocardial apical rotation (P<0.006) after 4 weeks of treatment (25.1+/-3.7 deg) versus baseline values (8.0+/-2.8 deg), while ejection fraction remained normal (78.5+/-3.5%). Thus, in the rat model, layer-specific assessment of myocardial function may detect cardiomyopathy at its early stages.