The ablation of simple and complex cardiac arrhythmias has become a first-line therapy in interventional cardiology and is mainly guided by conventional fluoroscopy. Cardiac magnetic resonance imaging (cMRI) allows exact three-dimensional (3D) visualization of complex anatomical structures and serves in the planning and implementation of ablation procedures. Post-procedural lesion visualization using cMRI can assess the success of ablation therapy and may distinguish potential complications. Performing ablation directly in the MRI scanner, with the option of anatomical substrate imagining, exact catheter navigation and real-time lesion visualization, holds the promise of improving success rates and safety in the interventional therapy of simple and complex arrhythmias.