Left ventricular blood flow patterns at rest and under dobutamine stress in healthy pigs

In this study the feasibility of 4D flow MRI during dobutamine ‐induced stress was assessed, and changes in intraventricular blood flow patterns are reported for the porcine heart. A decrease in cardiac volume, antero‐septally oriented diastolic inflow and high velocity flow was found, providing unfavorable conditions for diastolic vortex development compar ed with the rest condition. Intracardiac blood flow patterns are affected by the morphology of cardiac structures and are set up to support the heart's pump function. Exercise affects contractility and chamber size as well as pre ‐ and afterload. The aim of this study was to test the feasibility of four‐dimensional phase contrast cardiovascular MRI under pharmacological stress and to study left ventricular blood flow under stress. 4D flow data were successfully acquired and analysed in 12 animals. During dobutamine infus ion, heart rate and ejection fraction increased (82 ± 5 bpm versus 124 ± 3 bpm/46 ± 9% versus 65 ± 7%; bothp <  0.05). A decrease in left ventricular end‐diastolic volume (72 ± 14 mL versus 55 ± 8 mL;p <  0.05) and end‐systolic volume (40 ± 15 mL versus 19 ± 6 mL;p <  0.05) but no change in stroke volume were observed. Trans‐mitral diastolic inflow velocity increased under dobutamine and the trajectory of inflowing blood was directed towards the anterior septum with increased inflow angle (26 ± 5°) when compared with controls (15 ± 2°). In ...
Source: NMR in Biomedicine - Category: Radiology Authors: Tags: RESEARCH ARTICLE Source Type: research