Abstract 10897: Development of a Novel Shock Wave Catheter Ablation System -A Feasibility Study in Pigs in vivo
Background: Although radio-frequency catheter ablation (RFCA) is widely used for the treatment of tachy-arrhythmias, it has 2 unavoidable limitations caused by the usage of Joule heat as an energy source. One is the limited lesion depth due to decremental heat propagation with a resultant incomplete treatment of ventricular tachy-arrhythmias of epicardial focus and the other is the risk of thrombus formation with resultant thromboembolic events. In contrast, focused shock wave (SW) could cause tissue damages at an arbitrary point without heat generation. Thus, we aimed to develop a SW catheter ablation (SWCA) system to overcome the limitations of the current RFCA system.
Methods and Results: We developed a novel SWCA system consisting of a 2-polar 14Fr catheter equipped with a SW reflector at the tip. The energy source is a Q-switched Ho:YAG laser beam. The SW is generated by irradiation of a pulse laser beam through 0.6 mm core-diameter quartz optical fiber, then reflected by a reflector, and converged onto the focus point at 3.0 mm apart from the tip, where the overpressures ranged 35-45 MPa. We performed a feasibility test of our SWCA system with regard to creating atrioventricular (AV) node block in pigs in vivo. In 9 normal domestic male pigs (32.1±4.1(SD) kg), the SW catheter was inserted through right jugular vein and was located by reference to His bundle potential. In all pigs, the SWCA caused AV node injury, including junctional escaped rhythm in 2 and AV conduction disturbance in 7 (complete AV block in 6 and advanced AV block in 1). In 6 pigs, myocardial tissue damages, including AV nodal cell body atrophy, were noted immediately after the procedure. In order to examine the long-term effects, the remaining 3 pigs with persistent AV block were implanted with a pacemaker and were euthanized at 10.3±3.9 days after the SWCA treatment, where complete AV block was sustained and fibrotic myocardial lesions were noted at the treated sites. Importantly, the SWCA caused no acute or chronic fatal complications.
Conclusions: These results indicate that our novel SWCA system has an acceptable feasibility as a non-thermal ablation method for the treatment of tachy-arrhythmias to overcome the limitations of the RFCA therapy.
- © 2012 by American Heart Association, Inc.