Left ventricular access
Access to LV can generally be achieved through an anterograde
transseptal or aortic retrograde approach. However, access to the LV
could be challenging with previous heart surgery especially with the
presence of mechanical valves. In our series, 17 patients underwent
antegrade approach, 13 patients had retrograde aortic approach, 1
patient had a combined approach. Only 1 patient had a percutaneous
epicardial approach following a failed ablation through
antegrade-transseptal approach during the same procedure. As expected,
all patients with a mechanical mitral valve underwent retrograde
approach.
The presence of mechanical MV may slightly hinder ablation due to one
less route of access to the LV which may reduce maneuverability and
contact force. 26,27 Oftentimes, a combined approach
is required to maximize mapping and allow sufficient access to certain
regions e.g. the posterior papillary muscle.28
While no patients in our cohort had inaccessible LV, in certain
circumstances such as the presence of mechanical aortic and mitral
valves, non-conventional techniques might be necessary to access LV. In
such cases, options would include epicardial approach,29 transventricular septal puncture,30 transcoronary venous approach,31transapical approach,32 or trans–right atrial to the
LV approach.33
Percutaneous epicardial access can be challenging in patients with prior
cardiac surgery. A previous study reported that prior cardiac surgery
precludes LV access in most patients with only 20% success
rate.34 Other reports demonstrated the feasibility of
percutaneous epicardial approach in patients with prior cardiac
surgery.35,36 In one patient, we used transcutaneous
epicardial approach as endocardial mapping did not show an obvious exit
of the VT. Epicardial access was very challenging in this patient due to
adhesions associated with prior surgery and the presence of pectus
excavatum deformity. However, this was overcome with a more anterior
approach and a complete epicardial map was achieved with successful VT
ablation.