Real-time MRI guided percutaneous transthoracic left ventricular access and closure

Methods Sixteen Yorkshire swine underwent percutaneous transthoracic LV access and followed up to three months (n=8). All procedures were guided by real-time bSSFP MRI (Espree, Siemens) using two slices along the needle trajectory and a short-axis slice for cardiac monitoring. Transthoracic ventricular puncture was performed using a customized 18G active needle with integrated loop coil. Puncture trajectory was planned using realtime MRI to identify optimal LV puncture target and trajectory with respect to intraventricular and valvular structures (Figure 1A). After needle entry, an 18-French sheath was inserted and anticoagulation begun. Ventricular puncture hole was closed using a modified Amplatzer muscular VSD occluder with a titanium screw to improve MR appearance. A custom active delivery cable incorporating a loopless antenna was used to enhance the visibility of the device deployment. Occluder device was deployed by opening the distal disk at the endocardial surface (Figure 1B), separating pericardial layers by instillation of fluid into the pericardial space (“permissive pericardial tamponade”) in order to enable deployment of the proximal disk directly on top of the epicardial surface yet inside the pericardium (Figure 1C).