Magnetic navigation in invasive electrophysiological diagnostic and therapy]

Electrophysiological stimulation and ablation is currently performed with manually deflectable catheters of different lengths and curves. Disadvantages of conventional therapy are catheter stiffness, limited local stability, risk of dislocation or perforation, and reduced tissue contact in regions with difficult access. Fluoroscopy to control catheter movement and position may require substantial radiation times. Magnetic navigation was first applied for right heart catherization in congenital heart disease in 1991; the first electrophysiological application took place in 2003. Today, an ablation electrode with small magnets is aligned in the patient's heart by two external magnets positioned at both sides of the thorax. Antegrade and retrograde movement of the distal catheter tip are performed via an external device on the patient's thigh. Three-dimensional MRI scans acquired before intervention can be merged with electroanatomical reconstruction, leading to further reductions of radiation burden. During treatment of supraventricular tachyarrhythmias high local precision of magnetically guided catheters, good local stability, and a substantially reduced radiation time have been reported. First applications in ventricular tachyarrhythmias and complex congenital cardiac defects indicate a comparable effect. Limitations of this therapy are the application in left atrial procedures (open irrigated ablation catheters not yet available), difficult transaortic retrograde approach (high lead flexibility), and the considerable costs. Magnet-assisted navigation is feasible during percutaneous coronary interventions of tortuous coronary arteries and in positioning guidewires in coronary sinus side branches for resynchronisation therapy. Future applications will be complex left atrial procedures, magnetically guided cardiac stem cell therapy, local drug application, and extracardiac vessel therapy.