Detection of subclinical LV dysfunction by tissue Doppler imaging

Abstract

in a murine model of LV dysfunction suggests that abnormal tissue Doppler and strain rate indices may predict late cardiac dysfunction and death, at a time when conventional echocardiographic parameters are still normal. In this context, the study eludes the next step whether those new technologies may predict clinical endpoints such as heart failure and cardiac death, which is a crucial information for the clinical relevance of new technologies currently invading cardiology. To confirm the toxic impact of doxorubicin on the investigated myocardium, invasive haemodynamic measurements and also histological studies on cardiac apoptosis were taken as the gold standard of cardiac assessment. Tissue Doppler data were related to those haemodynamic and histological abnormalities and even of more importance to clinical outcome. This supports the concept to use tissue Doppler imaging for monitoring cardiac effects of new therapeutic strategies to prove cardiac efficacy or side effects. Another importantaspect of this study isthe fact that tissue Doppler imaging was used in a small animal model (mice). Currently, murine models of cardiac diseases play an increasingly important role in the understanding of the disease process and the evaluation of different therapies. In this respect, it is interesting to see that tissue Doppler imaging is also applicable in the experimental environment even in the presence of heart rates up to 500/min. 9 Although the original recordings of Doppler traces which were presented in this paper look reliable, the spatial resolution in mice hearts remains a matter of discussion, especially when endocardial velocitiesaregivenandtransmyocardialstrainratesarecalculated. In clinical application, we currently try to compensate for false measurements by tracking the region of interest throughout the cardiac cycle. It remains unclear how to do this technically in mice with high heart rates and thin LV walls. Maybe automated algorithms based on raw data measurements with speckle tracking facilities will solve this probleminthe future. First,applications havebeen presented and are under evaluation. 10