Abstract:The heart of an anencephalic baby can be used as a donor after death. There exists insufficient information in literature, however, for the possible morphological differences in anencephalic hearts. This study compares ventricular myocardial thicknesses of anencephalic fetuses with normal fetuses in the same gestational age group. The comparison was made histologically on the slices taken from three levels of anterior and posterior walls of the left and right ventricles and from two levels of the interventricu… Show more
“…We changed the iridium wire diameter from 150 µm to 254 µm, which should improve the lateral rigidity and the elastic stability by 7.7 times (keeping other parameters constant). The adjustment of the pitch from 0.5 mm to 1 mm changes n 0 from 8 to 4 turns for the same length corkscrew (4 – 4.5mm in accordance with 80% of predicted ventricular wall thickness for a human fetus at 27–34 gestational weeks [24]. This does not affect the elastic stability, but it improves the lateral rigidity by 15.4 times when combined with the increase of wire diameter.…”
This paper discusses the technical and safety requirements for cardiac pacing of a human fetus with heart failure and hydrops fetalis secondary to complete heart block. Engineering strategies to meet specific technical requirements were integrated into a systematic design and implementation consisting of a novel fetal micropacemaker, a percutaneous implantation system, and a sterile package that enables device storage and recharging maintenance in a clinical setting. We further analyzed observed problems on myocardial fixation and pacing lead fatigue previously reported in earlier preclinical trials. This paper describes the technical refinements of the implantable fetal micropacemaker to overcome these challenges. The mechanical performance has been extensively tested to verify the improvement of reliability and safety margins of the implantation system.
“…We changed the iridium wire diameter from 150 µm to 254 µm, which should improve the lateral rigidity and the elastic stability by 7.7 times (keeping other parameters constant). The adjustment of the pitch from 0.5 mm to 1 mm changes n 0 from 8 to 4 turns for the same length corkscrew (4 – 4.5mm in accordance with 80% of predicted ventricular wall thickness for a human fetus at 27–34 gestational weeks [24]. This does not affect the elastic stability, but it improves the lateral rigidity by 15.4 times when combined with the increase of wire diameter.…”
This paper discusses the technical and safety requirements for cardiac pacing of a human fetus with heart failure and hydrops fetalis secondary to complete heart block. Engineering strategies to meet specific technical requirements were integrated into a systematic design and implementation consisting of a novel fetal micropacemaker, a percutaneous implantation system, and a sterile package that enables device storage and recharging maintenance in a clinical setting. We further analyzed observed problems on myocardial fixation and pacing lead fatigue previously reported in earlier preclinical trials. This paper describes the technical refinements of the implantable fetal micropacemaker to overcome these challenges. The mechanical performance has been extensively tested to verify the improvement of reliability and safety margins of the implantation system.
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