Anne-Marie Koop

216 may underestimate the ejection fraction. Furthermore, the current protocol focuses on parameters used in clinical practice, representing global function. Parameters such as the tricuspid annular plane systolic excursion (TAPSE), fractional septum to freewall distance at the middle of the RV (fSFD), and fractional tricuspid annulus-apex distance change (fTAAD) were not analyzed. A major advantage of CMR is the ability to perform noninvasive, serial testing within one subject with a relatively high accuracy of volumetric and functional measurements. Because it is a measurement after which the animal can survive, unlike open-chest pressure-volume analysis, for example, it allows for a follow-up after the measurements. Although we have focused on cardiac dimensions and function, future uses of this technique include CMR-derived tissue characterization or scar tissue assessment by means of late gadolinium enhancement. This enables reduction of histopathological assessments, which will lead to a reduction in animals required for studies. More CMR research may optimize tissue characterization in humans and reduce iatrogenic damage due to biopsies. In conclusion, this protocol was created to provide guidance in the assessment of cardiac morphology and function in mice exposed to increased RV pressure load. The combination of PAB with CMR improves standardization and reproducibility . This makes it a very valuable technique for the study of signaling pathways involved in the failure of the pressure-loaded RV by the use of transgenic or knockout mice. ACKNOWLEDGMENTS We would like to thank P. Da Costa-Martins for her support with the animal experiments in this study. DISCLOSURES The University Medical Center Groningen has contracted with Actelion and Lilly for consultancy activities of R.M.F. Berger outside the content of this manuscript. The other authors declare that they have no competing interests.