Design and In Vivo Test of a Batteryless and Fully Wireless Implantable Asynchronous Pacing System.

Goal: The aim of this study is to develop a novel fully wireless and batteryless technology for cardiac pacing. METHODS: This technology uses radio frequency (RF) energy to power the implanted electrode in the heart. An implantable electrode antenna was designed for 1.2 GHz; then, it was tested in vitro and, subsequently, integrated with the rectifier and pacing circuit to make a complete electrode. The prototype implanted electrode was tested in vivo in an ovine subject, implanting it on the epicardial surface of the left ventricle. The RF energy, however, was transmitted to the implanted electrode using a horn antenna positioned 25 cm above the thorax of the sheep. RESULTS: It was demonstrated that a small implanted electrode can capture and harvest enough safe recommended RF energy to achieve pacing. Electrocardiogram signals were recorded during the experiments, which demonstrated asynchronous pacing achieved at three different rates. CONCLUSION: These results show that the proposed method has a great potential to be used for stimulating the heart and provides pacing, without requiring any leads or batteries. It hence has the advantage of potentially lasting indefinitely and may never require replacement during the life of the patient. SIGNIFICANCE: The proposed method brings forward transformational possibilities in wireless cardiac pacing, and also in powering up the implantable devices.

Anatomical basis of central venous catheter fracture.

Central venous catheter fracture is a rare complication of long-term indwelling subclavian venous access. Subclavian vein access has been the recommended approach for placing central venous catheters. The anatomical landmark method for subclavian access remains a highly successful and nonequipment-dependent method for rapid central access. More recently, the internal jugular vein approach has emerged as the preferred route for long-term central venous access. However, variations in internal jugular vein anatomy make the landmark method less reliable. Use of two-dimensional real-time ultrasound during internal jugular vein access is associated with better success, a lower complication rate, and faster access. A case of central venous catheter fracture initiated an internal review of long-term central venous access procedures. We have converted to a predominantly internal jugular vein approach. This case report and literature review may assist other physicians and institutions in re-evaluating long-term central venous access protocols.