- Oral presentation
- Open Access
Differential response of the left and right ventricles to pressure overload revealed with diffusion tensor MRI tractography of the heart in vivo
© Mekkaoui et al; licensee BioMed Central Ltd. 2015
- Published: 3 February 2015
- Left Ventricle
- Pulmonary Hypertension
- Right Ventricle
- Pressure Overload
- Helix Angle
The left ventricle (LV) can tolerate pressure overload from hypertension or aortic stenosis for many years. In contrast, the right ventricle (RV) adapts to pulmonary hypertension only if this develops at birth, while in the adult heart severe and often fatal RV failure develops. We hypothesized that i) these divergent responses could be due to differences in myofiber architecture in the free walls of the LV and RV and that ii) adaptive changes to pressure overload would be seen in the LV but not the RV.
Mice subjected to aortic banding (AB), pulmonary artery banding (PB), and healthy controls, (n=6 per group), were imaged in vivo, ensuring that myofiber architecture was imaged under true loading conditions. Diffusion Tensor MRI (DTI) tractography was performed at 9.4T with a 1500 mT/m gradient, a motion-compensated Stejskal-Tanner sequence, 24 gradient directions, b-value of 500 s/mm2, and an isotropic resolution of 156 μm3 . Fiber tracts were color-coded by their helix angle (HA) .
The LV contains a large number of circumferential myofibers at baseline and undergoes a rightward shift in fiber architecture in response to pressure overload. In contrast, the RV contains few circumferential myofibers, and its architecture remains largely unchanged in response to increased load. These differences may account for the inability of the RV to tolerate acquired pulmonary hypertension in adulthood.
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