Noninvasive stereotactic radioablation for the treatment of atrial fibrillation: First‐in‐man experience

Figures

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  Figure 1. Placement of an internal fiducial point to improve radioablative accuracy. This shallow left anterior oblique projection fluoroscopic image demonstrates the position of the fiducial marker placed via right internal jugular vein access, and affixed to the right side of the interatrial septum, in close proximity to the left atrial target. Compensation for cardiorespiratory motion during radioablation is achieved by the external beam delivery system through tracking of fiducial movement using planar xray

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  Figure 2. Anatomical considerations in tailoring the radioablative lesion set. Treatment dosing for Patient 2 is displayed on the 3D rendered left atrial volume using the radioablation treatment planning software (Cardioplan, Cyberheart, Inc and Cyberknife, Accuray Inc) Panel A shows a posterior‐anterior projection of the left atrium with the esophagus in situ to demonstrate the arrangement of the lesion set to minimize esophageal dosing. Panel B and C are additional posterior‐anterior and right lateral caudal views with the esophagus removed. Red signifies dosing at or above 90%, green (60%‐90%) and blue (<60%) of the target dose of 25 Gy. LSPV:Left superior pulmonary vein; LIPV:left inferior pulmonary vein; RSPV:right superior pulmonary vein, RIPV:right inferior pulmomary vein; LV:left ventricle

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  Figure 3. Planning and delivering steretotactic radioablation to the left atrium. Preprocedural CT scan of the chest obtained for patient 1; treatment volume planning requires defining a treatment volume using orthogonal imaging planes. Panel A and B show transverse and sagittal planes through the left atrium demonstrating radioablative isodose contours within and around the planned treatment volume, P, shown bounded by the orange line. Panel C demonstrates the calculated multiple beam angles used to deliver and concentrate radioablative energy within this treatment volume. Panel D shows the proportion of dose delivered to the targeted atrial myocardium and other key nearby visceral tissues as a function of tissue volume; it can be seen that approximately 89% of the target volume received at least 25 Gy

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  Figure 4. Cardiac magnetic resonance imaging demonstrating left atrial fibrosis in the radioablation treatment zone. Cardiac MRI for Patient 2, performed one year post stereotactic radioablation therapy, is shown. In this four‐chamber view, areas of late gadolinium enhancement (arrows), consistent with fibrosis, are seen within the left atrium septal and laterally consistent with treatment areas