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.