Catheter Ablation Versus Radio-Ablation for Ventricular Tachycardia: a Randomized Controlled Trial

Currently standard of care involves surgical resection of myocardial scarring in structural heart disease. Imaging is performed to identify culprit areas for ablation, pre procedural imaging involves echocardiography, CT scanning and PET imaging to assess cardiac function, ischemia, inflammation and scarring. Radiofrequency energy is delivered via catheter to the targets and is performed under sedation or anesthesia using multiple catheters placed in the heart while the patient is anticoagulated. A conventional approach will be used advancing multiple catheters via femoral veins and/or arteries under a combination of fluoroscopic, ultrasound and electroanatomic guidance. Ablation targets include an arrhythmogenic focus or the critical isthmus of the VT circuit and/ or substrate identified on preprocedural imaging or low voltage areas, "scar", identified during endocardial mapping. CA procedures for VT are often long, averaging approximately 5 hours .

Patients undergoing a non-invasive RA procedure for VT similarly require medical stabilization and multimodal imaging prior to treatment. A non-invasive electrophysiology study is performed under light sedation using ECGi mapping. This procedure requires only the placement of an IV cannula for light sedation, uses the ICD to stimulate VT which is mapped in real time using the ECGi mapping system. The multimodal imaging data is digitally fused and combined with the ECGi data to identify the VT circuit(s) and to attain the targets for radio-ablation. This analogue process is performed off-line by a physician team. The treatment plan is sent for alignment on a 4D planning CT performed with breath holding in the radiotherapy suite. Final treatment targets are reviewed by the local treating team and discussed with our collaborators remotely. Thereafter the patient is booked for a 15 minute out-patient radiotherapy treatment performed on a standard linear accelerator.