Feasibility of An Entirely Extracardiac, Minimally Invasive,Temporary Pacing System

Circ Arrhythm Electrophysiol. 2019 Jul;12(7):e007182. doi: 10.1161/CIRCEP.119.007182. Epub 2019 Jul 3.

Abstract

Background: A completely extracardiac pacing system provides the potential for clinical advantages over existing device alternatives that require intravascular, endocardial, or epicardial contact. Preliminary studies evaluating the feasibility of cardiac pacing with a lead in the anterior mediastinum, outside the pericardium and circulatory system have been completed. These studies examined (1) the anatomic access route, (2) the usability of a delivery tool to facilitate lead placement, and (3) the pacing performance of the extracardiac lead.

Methods: Feasibility evaluations included (1) a retrospective computed tomography analysis to characterize anatomic variations related to lead access, (2) accessing the anterior mediastinum in cadavers and human subjects using a custom delivery tool, and (3) acute clinical pacing performance.

Results: Major findings: (1) A total of 166 (95%) out of 174 patients had a viable lead access path through the fourth, fifth, or sixth intercostal space. (2) Access to the targeted implant location using a delivery tool was successful in all 5 cadavers and 3 humans without use of fluoroscopy and with an average lead delivery time of 121±52 s. No damage to the lung, pericardium, heart, or internal thoracic vessels occurred. (3) Pacing performance was tested in 6 human subjects showing a threshold voltage of 4.7 V (2.7-6.7), threshold pulse width of 1.8 ms (1.0-2.5), and an impedance of 1205 Ω (894-1786). R-wave amplitudes measured 9.6 mV (5.6-12.0).

Conclusions: Results support the feasibility for this completely extracardiac pacing method in a heterogeneous patient population, using a minimally invasive, parasternal, delivery approach and with adequate sensing and thresholds suited for temporary pacing.

Keywords: bradycardia; cadaver; extra-cardiac pacing; pacemaker; pericardium; temporary pacing.

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Arrhythmias, Cardiac / diagnosis
  • Arrhythmias, Cardiac / physiopathology
  • Arrhythmias, Cardiac / therapy*
  • Cadaver
  • Cardiac Pacing, Artificial*
  • Dissection
  • Equipment Design
  • Feasibility Studies
  • Female
  • Humans
  • Male
  • Mediastinum* / diagnostic imaging
  • Middle Aged
  • Pacemaker, Artificial*
  • Radiography, Interventional
  • Retrospective Studies
  • Tomography, X-Ray Computed
  • Young Adult