Video Assisted Pericardioscopic Surgery: Assesment of Redo-Operation and pacemaker parameters in a Chronic Ovine Model

Objective: Appliance of Video-Assisted-Pericardioscopic-Surgery (VAPS) as a non-transthoracic/-pleural, subxiphoid approach for epicardial lead implantation has proven good acute results concerning feasibility, safety and latitude inside the pericardial cavity in an animal model. The ability of reoperation from the same approach as well as long-term in-vivo effects of VAPS-implanted pacemaker-leads with their on-site electrical and mechanical behaviour have not been assessed yet and are therefore the aim of this study.

Methods: Six adult female sheep were used in this investigation. The animals were divided into 2 groups: 1) VAPS applied without lead implantation; 2) VAPS-implantation of small-calibre (4 Ch) epicardial screw-in leads onto each chamber (Σ: 16), where left sided leads were representatively connected to a dual-chamber pacemaker for follow-up assessments, held after 4, 8 and 12 weeks post implantation. Lead position was confirmed by biplane fluoroscopy. After 6 months, reoperation was conducted from the same subxiphoid entry point in order to investigate A) feasibility of re-operation, B) pacemaker values and C) intrapericardial adhesions. The latter was classified in degrees depending on the possibility of dissection with a rigid endoscope: I° no relevant, II° minor (easily dissectible, no bleeding), III° moderate (partially dissectible with possible epicardial oozing) and IV° severe adhesions (not dissectible).

Results: A) Reentry through the identical pericardial entry-site was not feasible in both groups, although yielding horizontally in the immediate vicinity allowed simple entrance. B) Throughout the follow-up pacing parameters showed satisfying values. Lead-dislodgement occurred in one (right atrial) out of 16 leads. C) Apart from the pericardial entry-sites, both groups showed I° to II° adhesions, except the immediate area of the implanted leads (III°) in group 2. Removal of the implanted leads was simple by counterrotation.

Conclusion: Our study revealed a fair dislodgement rate of 6.2% after 6 months for this specific screw-in lead. Reoperation from the same subxiphoid approach is feasible, if the identical pericardial entry point is avoided. The intrapericardial adhesions caused by VAPS are mild (I°-II°), whereas implanted leads generate more profound encircling adhesions (III°), yet permitting lead-removal/-implantation if necessary. In summary VAPS can be used confidently in man for epicardial lead implantation.