[Cryothermal energy: a new perspective for interventional therapy of cardiac arrhythmias?]

Cryothermal ablation is a new method in cardiac electrophysiology for the percutaneous catheter ablation of cardiac arrhythmias. Cryothermal mapping make possible the functional assessment of a particular site before permanent ablation. In this way the targeted tissue may be confirmed as safe for ablation. This is useful in high-risk ablation, for example next to the AV node. In this method pressurized liquid nitrogen is delivered to the tip of the ablation catheter. Cooling of the tip is temperature-controlled. Cryothermal balloons are also available, in addition to standard cryothermal catheters, for the isolation of pulmonary veins. The tissue freezing provides high catheter stability. Cryothermal lesions have a similar depth to radiofrequency energy, but area and volume of the lesions are reduced. Furthermore, they are well demarkated and the incidence of thrombus-formation is reduced. Cryothermal ablation has been evaluated for the treatment of AV-nodal reentry tachycardia (AVNRT), accessory pathways, atrial flutter, atrial fibrillation and ventricular tachycardias originating in the right ventricular outflow tract. Current experience indicates that the method is painless for the patient and safe. However, its use seems to be limited by a longer ablation time and lower efficacy. Further studies evaluating long-term success of cryothermal ablation are warranted. For high-risk ablations cryothermal energy is helpful and should be used for para-Hisian accessory pathways and difficult cases of AVNRT. It has a widely demonstrated safety profile. The clinical efficacy will have to be evaluated in further studies.