Acute and chronic performance evaluation of a novel epicardial pacing lead placed by percutaneous subxiphoid approach in a canine model.

BACKGROUND

Endovascularly implanted leads risk vascular injury and endocarditis, and can be difficult to locate in desired positions for LV pacing. We evaluated the acute and long-term stability, electric performance and histopathology of a percutaneously placed intrapericardial lead (IPL).

METHODS AND RESULTS

Twelve adult mongrel dogs underwent defibrillator implants incorporating IPLs. Successful uncomplicated percutaneous implantation of an IPL was achieved in all. Early fluoroscopic shift noted with 3 of 6 of the initial version IPL-1 was not seen with the modified IPL-2. Mean±95% confidence interval bipolar capture threshold at 0.5-ms pulse width for the IPL increased from 0.69±0.14 V at implant to 1.50±0.34 V (P=0.003) at 12 weeks. The 12-week thresholds were higher for IPL compared with right ventricular endocardial leads (0.75±0.33 V; P=0.001) but not different compared with coronary sinus leads (1.33±0.58 V; P=0.994). IPL impedance increased from 742±46 Ω at implant to 1066±207 Ω at 12 weeks (P=0.007). R-wave amplitude at 12 weeks was 8.37±1.52 mV. There was no important phrenic nerve stimulation from IPL pacing. Histopathology in 8 animals showed adequate adhesion of the electrodes or mesh to the epicardium without damage to underlying vasculature. There was no evidence for late pericardial inflammation or effusion.

CONCLUSIONS

The IPL demonstrated adequate stability of position and acceptable electric parameters without chronic pericardial inflammation in this canine model and offers a potential alternative to endocardial pacing leads.