Feasibility of Echocardiography-guided Percutaneous Transapical Lead Implantation for Intraventricular Septal Pacing: Acute and 3-Month Evaluation

Background: Transvenous lead implantation often faces challenges regarding venous access and lead-related complications. This study evaluated the feasibility and safety of a novel echocardiography-guided percutaneous transapical intraventricular septum (PTAIVS) pacing approach in an animal model. Methods: Twelve adult dogs underwent PTAIVS lead implantation guided by transthoracic and transoesophageal echocardiography. Leads were introduced percutaneously through the apex and fixed in the mid-to-basal septum. The first six dogs were implanted with a pacing set with a coaxial introducer needle (CareFusion) and a Model 3830 lead (Medtronic), whereas an improved pacing set with an extended helix lead was used in the next six dogs. The first three dogs were used for evaluation of acute gross pathology, with the remaining nine followed up over a period of 4-12 weeks. Pathological examinations were performed at the end of the follow-up period. Results: Successful lead placement without procedural complications was achieved in all dogs, with a mean (± SD) procedural time of 28.8 ± 4.8 min. At implantation, the median (interquartile range) capture threshold was 1.7 (0.85-2.50) V, the R-wave amplitude was 6.80 (6.13-13.00) mV and impedance was 536 (510-922) Ω. In the initial six dogs in which the unmodified pacing system was used, lead dislodgement occurred at the 1-month follow-up. Modifications to the system eliminated dislodgement at 1 month, but varying degrees of displacement were observed by 3 months. Conclusion: This study demonstrates the initial technical feasibility of echocardiography-guided PTAIVS pacing, offering a potential alternative to traditional transvenous methods. However, further refinements are essential to improve long-term lead stability.