Investigation of the effect of deep-breathing on the caval circulation in patients with cardiac rhythm disorders using 5D radial Flow MRI

International audience ; INTRODUCTION: Conventional assessment of thoracic blood flow using three-dimensional cardiac-resolved (4D) phase contrast MRI (PC-MRI) is not suitable for the assessment of the respiratory pump effect because standard pencil beam respiratory gating is performed in only one specific respiratory phase. To overcome this limitation, free-running self-gated non-cartesian 4D Flow MRI acquisitions have been developed. Ma et. Al. demonstrated recently the feasibility of assessing the respiratory related changes in the caval circulation under physiological breathing conditions using a 5D radial phase contrast acquisition with compressed sensing reconstruction1.It is known that deep inspirations increase strongly the systemic venous return with immediate repercussions on right ventricular stroke volume. At the same time, pulmonary resistance is increased leading to decreased inflow in the left chambers, which will be compensated in the following heartbeat. In patients with atrial myopathy, such as in the presence of atrial fibrillation, all these quick adjustments might be more difficult or not possible. Although a few studies have explored alterations of hemodynamic parameters on in the left atrium in patients with atrial fibrillation, the effect of deep breathing has not yet been assessed.Therefore, our aim was to assess the impact of deep breathing on hemodynamic parameters in patients with atrial fibrillation, paroxysmal and permanent, and in a healthy population as compared to normal breathing.METHODS: We included 4 patients with paroxysmal AF, 4 patients with permanent AF, and 5 age matched healthy volunteers. All subjects underwent MR imaging that included standard of care cardiac function assessment using 2D cine bSSFP sequences and a free-running 3D radial Flow acquisition that we implemented on a 1.5T Philips Ingenia system (Philips, Best, The Netherlands)2. The 3D radial trajectory is based on a spiral phyllotaxis pattern for k-space sampling adapted from Piccini et al.3. The ...