Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study

Background

Pacemaker implantation in infants and small children is limited to epicardial lead placement via open chest surgery. We propose a minimally invasive solution using a novel percutaneous access kit.

Objective

To evaluate the acute safety and feasibility of a novel percutaneous pericardial access tool kit to implant pacemaker leads on the epicardium under direct visualization.

Methods

A custom sheath with optical fiber lining the inside wall was built to provide intrathoracic illumination. A Veress needle inside the illumination sheath was inserted through a skin nick just to the left of the xiphoid process and angled toward the thorax. A needle containing a fiberscope within the lumen was inserted through the sheath and used to access the pericardium under direct visualization. A custom dilator and peel-away sheath with pre-tunneled fiberscope was passed over a guidewire into the pericardial space via modified Seldinger technique. A side-biting multipolar pacemaker lead was inserted through the sheath and affixed against the epicardium.

Results

Six piglets (weight 3.7–4.0 kg) had successful lead implantation. The pericardial space could be visualized and entered in all animals. Median time from skin nick to sheath access of the pericardium was 9.5 (interquartile range [IQR] 8–11) min. Median total procedure time was 16 (IQR 14–19) min. Median R wave sensing was 5.4 (IQR 4.0–7.3) mV. Median capture threshold was 2.1 (IQR 1.7–2.4) V at 0.4 ms and 1.3 (IQR 1.2–2.0) V at 1.0 ms. There were no complications.

Conclusion

Percutaneous epicardial lead implantation under direct visualization was successful in six piglets of neonatal size and weight with clinically acceptable acute pacing parameters.     

Continuous fiberoptic arterial oxygen tension measurements in dogs

An experimental study using a new fiberoptic sensor for the continuous intraarterial measurement of oxygen tension is described. This optode sensor uses the phenomenon of fluorescence quenching to determine the oxygen tension of the surrounding medium. To assess the accuracy of this device, we anesthetized 4 dogs and monitored them continuously with arterial catheters and an intraarterial optode probe, and intermittently with arterial blood gas analysis. The inspired oxygen fraction was varied from 1.0 to 0.1, and arterial blood gases were measured for comparison with the optode reading. Two hundred ninety data sets yielded a correlation coefficient of 0.96, with a linear regression slope of 0.98 and intercept of 5.1 mm Hg. In the 72 data sets from the last dog, the bias and precision of the optode arterial oxygen tension values were –10.3 mm Hg and 20.0 mm Hg, respectively. The optode probe was easily inserted through a 20-gauge catheter and did not interfere with continuous arterial pressure measurement or blood sampling. This study suggests that the optode has great potential as a continuous, real-time monitor of arterial oxygen tension.