Ethanol Injection for the Treatment of VT
Trans-coronary arterial injection has been established as a potentially useful therapeutic alternative in VTs that fail to respond to RF (18-21). However, the limitations of this technique include inadvertent coronary artery damage, lacking of a suitable branch to deliver the ethanol and non-homogenized tissue injury paradoxically producing new VT substrate. Therefore, some other investigators tried to use venous route for ethanol delivery. Wright et al. explored the retrograde venous approach in a canine model showing the feasibility and efficacy.(22) Kreidieh et al. used retrograde coronary venous ethanol ablation as a bail-out approach to failed VT ablation, particularly from left ventricular summit.(23) Meanwhile, transcatheter intra-myocardial ethanol injection was tested in animal models.(24-28) However, so far this technique has not been reported in human beings and this special catheter has not been widely used clinically. In our study, we directly injected the ethanol to the myocardium to reinforce surgical ablation. As a supplementary treatment, it worked in association with surgical RF ablation and achieved the final success. To our knowledge, this is the first study describing the safety and efficacy of intramural ethanol injection via surgical approach in VT patients. In our animal study, epicardial ethanol injection created homogenous and well-circumscribed lesions which could be less arrhythmogenic. Meanwhile, the impact of small dosage of ethanol injection on cardiac function is still not significant in the long-term follow up. Therefore, the efficacy of ethanol injection at the critical VT sites is promising. This novel technique can be used to supplement surgical epicardial RF ablation.