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Preclinical testing and optimization of a novel fetal micropacemaker

      Complete heart block (CHB) in the human fetus may result in progressive bradycardia with the development of hydrops fetalis in one-fourth of these pregnancies.
      • Lopes L.M.
      • Tavares G.M.
      • Damiano A.P.
      • Lopes M.A.
      • Aiello V.D.
      • Schultz R.
      • Zugaib M.
      Perinatal outcome of fetal atrioventricular block: one-hundred-sixteen cases from a single institution.
      • Eliasson H.
      • Sonesson S.E.
      • Sharland G.
      • et al.
      for the Fetal Working Group of the European Association of Pediatric Cardiology
      Isolated atrioventricular block in the fetus: a retrospective, multinational, multicenter study of 175 patients.
      If hydrops fetalis occurs and the fetus cannot be delivered because of prematurity or other clinical concerns, fetal demise is nearly inevitable. Although the degree of myocardial dysfunction due to antibody-mediated damage in congenital CHB is variable, successful pacing of a fetus with CHB and hydrops fetalis theoretically could allow resolution of hydrops in several weeks and permit an otherwise normal gestation. However, historical attempts at pacing human fetuses have invariably failed, with no survivors reported to date.
      • Walkinshaw S.A.
      • Wlech C.R.
      • McCormack J.
      • Walsh K.
      In utero pacing for fetal congenital heart block.
      • Assad R.S.
      • Zielinsky P.
      • Kalil R.
      • Lima G.
      • Aramayo A.
      • Santos A.
      • Costa R.
      • Marcial M.B.
      • Oliveira S.A.
      New lead for in utero pacing for fetal congenital heart block.
      • Carpenter Jr, R.J.
      • Strasburger J.F.
      • Garson Jr, A.
      • Smith R.T.
      • Deter R.L.
      • Engelhardt Jr, H.T.
      Fetal ventricular pacing for hydrops secondary to complete atrioventricular block.
      • Eghtesady P.
      • Michelfelder E.C.
      • Knilans T.K.
      • Witte D.P.
      • Manning P.B.
      • Crombleholme T.M.
      Fetal surgical management of congenital heart block in a hydropic fetus: lessons learned from a clinical experience.
      To address this problem, we designed a single-chamber pacing system that is self-contained and can be percutaneously implanted in the fetus without exteriorized leads, thereby permitting subsequent fetal movement without risk of electrode dislodgment (Figure 1).
      Figure thumbnail gr1
      Figure 1Implantation equipment. A: Implantation cannula with trocar inside. B: Sharp tip of trocar protruding from end of cannula. C: Micropacemaker inside its implantation sheath protruding through cannula. D: Micropacemaker device with distal electrode screw connected to the micropacemaker (3.475-mm diameter, 18 mm long) via a coiled flexible lead.

      Abbreviations:

      CHB (complete heart block)

      Keywords

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