Experimental Study on the Effectiveness and Safety of Radiofrequency Catheter Ablation With the Cooled Ablation System

Abstract

Experimental in vitro and in vivo studies were performed to assess the effectiveness and safety of the cooled-tip catheter and the Cooled Ablation System, which enables the creation of deeper and wider burn lesions in the myocardial tissue using radiofrequency current. This system was confirmed to consistently create large burns by cooling the catheter tip with circulating water within the catheter, even under unfavorable conditions. On the other hand, unfavorable effects, as a result of over burning, such as explosive vaporization within the tissue (the `pop' phenomenon), tissue carbonization, coronary artery injury and lung injury were identified. `Pop' was difficult to predict, but it is important to know how it can be avoided. No `Pop' was seen without first observing an impedance decrease, thus it was considered safe to decrease the radiofrequency current if the impedance began to decrease. This system will be very effective for ablation of refractory arrhythmias, such as ventricular tachycardia or atrial flutter, but it is recommended that only experienced electrophysiologists use this system to avoid serious complications. (Circ J 2003; 67: 154 - 158)