title: Super-selective electrical stimulation of the left ventricle via a miniaturized magnetized stimulation wire: proof of concept study.
abstract: Cardiac resynchronization therapy provides a treatment option for patients with congestive heart failure. Electrodes are usually advanced via the cardiac venous system (CVS). Placement is often hampered by small vessel diameter or tortuosity. The aim of this study was to develop and test a magnetized stimulation wire (MSW) capable of being navigated into small and tortuous CVS branches. Therefore, a conventional guide wire with a permanent magnet and a single stimulation electrode at its tip was coated with iridium oxide at the distal end and insulated except for the very tip (coating thickness: 500 nm, active uncoated area: 10 mm(2)). The MSW was designed to allow for a remote magnetic steering using a magnetic navigation system (MN) (Stereotaxis™). After in vitro testing of the electrical properties, the MSW was tested in an animal model (n=6 sheep): the MSW was placed in a CVS side branch and navigation characteristics of the MSW were determined. The effective (unipolar) pacing threshold was 4.9±2.4 V (at 2 ms pulse width). The rheobase was 1.89±0.44 V and the chronaxie time was 0.75±0.7 ms. The MSW could be navigated into small CVS branches with reasonable MN properties. This could allow stimulation at CVS sites currently not accessible for conventional stimulation catheters or electrodes.
authors: Department of Cardiology, RWTH Aachen University, Aachen, Germany. c.knackstedt@dshs-koeln.de
authors: Christian
authors: C
authors: Knackstedt
authors: Thomas
authors: T
authors: Schimpf
authors: Andreas
authors: A
authors: Napp
authors: Boerge
authors: B
authors: Wessling
authors: Christine
authors: C
authors: Rothe
authors: Karl
authors: K
authors: Mischke
authors: Uwe
authors: U
authors: Schnakenberg
authors: Patrick
authors: P
authors: Schauerte
mesh_terms: D000818:Animals; D058409:Cardiac Resynchronization Therapy Devices; D004567:Electrodes, Implanted; D004867:Equipment Design; D019544:Equipment Failure Analysis; D006329:Heart Conduction System / Q000502:physiology*; D008280:Magnetics / Q000295:instrumentation*; D008904:Miniaturization; D010865:Pilot Projects; D012680:Sensitivity and Specificity; D012756:Sheep; D016277:Ventricular Function, Left / Q000502:physiology*