Chronic performance of subxiphoid minimally invasive pericardial Model 20066 pacemaker lead insertion in an infant animal model

Purpose: To describe chronic performance of subxiphoid minimally invasive pacemaker lead insertion in a piglet model. Methods: Minimally invasive pacemaker lead implantation was performed through a 10-mm incision under direct visualization using the PeriPath port. Epicardial access was obtained and the commercially available Medtronic Model 20066 pacemaker lead was inserted into the pericardial space and epicardial fixation was performed using the side-action helix. The lead was connected to a pacemaker generator in a para-rectus pocket. Animals underwent a 12–14-week observation period and lead impedances, R-wave amplitudes, and ventricular capture thresholds were tested biweekly. After the survival period, animals were euthanized and gross and histopathology were performed. Results: Subxiphoid minimally invasive pacemaker lead placement was performed in 8 animals (median 4.9 kg) with 100% acute success. Median procedure time was 65 min (IQR 60.5–77). At implant, median lead impedance was 650 Ω (IQR 244–984), R-wave amplitude 11.1 mV (IQR 8–12.3), and ventricular capture threshold 1.5 V @ 0.4 ms (IQR 1–2.6). Over a median survival period of 13 weeks, there was a median lead impedance change of + 262 Ω (IQR 5.3–618.3), R-wave change of − 4.5 mV (IQR − 7.1–− 2.7) and capture threshold change (1.0 ms) of + 1.5 V (IQR 0–3.3). At autopsy, epicardial fixation sites showed fibrovascular proliferation and minimal chronic inflammation. Conclusions: Subxiphoid pericardial pacemaker placement is safe and effective in a piglet model. Further study and development of leads designed for pericardial placement are warranted.