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.