Surgical VT Ablation Techniques
With improvements in catheter-based ablation technology, the outcomes of
percutaneous VT ablation have also been improved. However, inadequate
contact force, epicardial fat tissue, substrate close to the coronary
arteries and intramural foci limited the success with percutaneous
ablation. The other important issue was pericardial adhesion. Soejima et
al described a series of 6 patients with pericardial adhesion, for which
a hybrid subxiphoid surgical window approach to treat VT in
electrophysiology (EP) lab was adopted.(16) However, the subxiphoid
approach allowed inadequate access to anterior and lateral regions.
Michowitz then used limited anterior thoracotomy in patients with
previous cardiac surgery and pericardial adhesion in EP lab.(17) This
approach could permit access to the whole anterior and lateral wall as
well as the apex. Anter et al reported their surgical cryoablation
experience in 8 non-ischemic cardiomyopathy patients with refractory
VT.(15) Two patients died of heart failure and sepsis eventually, while
the other 6 patients had significant reduction in VT burden. All these
studies emphasized that direct epicardial ablation via limited
thoracotomy or even open chest approach could be effective in difficult
VT cases.
Compared with percutaneous access, surgical RF ablation has the
following advantages: (1) contact force is ensured by pressing the
catheter tip against epicardium, which makes deeper lesions (Figure 1);
(2) under direct vision, the substrates in close proximity to the
coronary arteries could be ablated safely and adequately;(3) other
concomitant surgical procedures could be done simultaneously; (4) in
patients with CRT indication, the LV lead can be placed at a more
electrophysiological site (high voltage, latest activation, away from
scar) guided by 3-D electroanatomic mapping system. However, the
limitation of this traumatic approach is apparent. This approach can
only be served as the last resort for patients with frequent VT attack
and refractory to both antiarrhythmic drugs and conventional ablation
therapy, especially those with frequent ICD shocks.