Percutaneous epicardial placement of a prototype miniature pacemaker under direct visualization: An infant porcine chronic survival study

Abstract

Introduction: Pacemaker implantation in infants typically consists of surgical epicardial lead placement with an abdominal generator. Here, we describe the chronic performance of our minimally invasive prototype miniature pacemaker implanted under direct visualization in an immature porcine model. Methods:Twelve piglets underwent miniature pacemaker implantation. A self-anchoring twochannel access port was inserted into a 1 cm incision in the subxiphoid space, and a thoracoscope was inserted into the main channel to visualize the thoracic cavity under insufflation. The pacemaker leadlet was inserted through a sheath via secondary channel and affixed against the epicardium using a helical side-biting electrode. The miniature pacemaker was tucked into the incision, which was sutured closed. Ventricular sensing, leadlet impedance, and capture thresholds were measured biweekly. A limited necropsy was performed after euthanasia.Results: Nine piglets were followed for a median of 78 (IQR 52-82) days and gained 6.6 ± 3.2 kg.Three animals were censored from the analysis due to complications unrelated to the procedure. Capture thresholds rose above maximal output after a median of 67 (IQR 40-69) days. At termination, there was a significant decrease in R-wave amplitude (P = .03) and rise in capture thresholds at 0.4 ms (P = .01) and 1.0 ms pulse widths (P = .02). There was no significant change in leadlet impedance (P = .74). There were no wound infections.Conclusions: There were no infections following minimally invasive implantation of our prototype miniature pacemaker. Improvements to epicardial fixation are necessary to address diminished leadlet efficacy over time. K E Y W O R D S epicardial, miniature pacemaker, minimally invasive, pediatric, porcine 1 Pacing Clin Electrophysiol. 2020;43:93-99. c

Surgical pericardial adhesions do not preclude minimally invasive epicardial pacemaker lead placement in an infant porcine model

“…This procedure has been described extensively in our previous work. [13][14][15][16] The experimental group (or adhesion group) underwent left thoracotomy and partial pericardiectomy followed by a 6 week recovery period to develop intrathoracic adhesions. Other studies have used similar animal models to develop adhesions by performing a partial pericardiectomy and epicardial irrigation to simulate congenital heart surgery.…”

“…Median sensed R-wave amplitudes and capture thresholds at 0.4 and 1.0 ms pulse width were not statistically significantly different between the adhesion and control groups. Sensing and capture thresholds were both superior in T A B L E 1 Adhesion volumes and strengths were noted during each thoracoscopic procedure and graded on the scale defined by Kojima et al, volume: (a) one-third of the cardiac surface is covered, (b) two thirds of the cardiac surface is covered, (c) ninety percent of the cardiac surface is covered; strength: (a) adhesion tissue is easily divided, (b) tissue is partially divided, and (c) tissue is completely adhered to epicardium Total procedure time* 25 (21-43) 13 (11)(12)(13)(14)(15)(16)(17)(18)(19) Abbreviation: IQR, interquartile range.…”

“…The control group underwent acute implantation of a pacing lead (Model 4796, Medtronic Inc, Mounds View, MN) using our minimally invasive thoracoscopic approach with PeriPath. This procedure has been described extensively in our previous work 13–16 . The experimental group (or adhesion group) underwent left thoracotomy and partial pericardiectomy followed by a 6 week recovery period to develop intrathoracic adhesions.…”

Percutaneous epicardial pacing in infants using direct visualization: A feasibility animal study

“…Previous studies have proposed alternative surgical methods to decrease the invasiveness of lead implantation, either with different, smaller surgical incisions, or thoracoscopy via multiple ports 19–24 . Our group has previously established the feasibility of epicardial lead placement using a single incision access port to successfully implant ICDs and prototype miniature pacemakers under direct visualization in acute and chronic porcine studies 25–28 . However, all of the prior implants still required a small surgical incision.…”

“…[19][20][21][22][23][24] Our group has previously established the feasibility of epicardial lead placement using a single incision access port to successfully implant ICDs and prototype miniature pacemakers under direct visualization in acute and chronic porcine studies. [25][26][27][28] However, all of the prior implants still required a small surgical incision. A novel, truly percutaneous approach that requires just a single needle stick represents a significant improvement in the invasiveness of this procedure for infants and small children.…”