On the Management of Ventricular Arrhythmias Following Leadless Pacemaker Implantation

Ahmad et al. 1 present an interesting case of a patient undergoing leadless pacemaker placement with subsequent ventricular fibrillation (VF) induced cardiopulmonary arrest.As they mention, there are several published case reports of ventricular tachycardia (VT) and VF proximate to implantation of the Micra™ device (Medtronic, Minneapolis, MN, USA).In their clinical scenario, a leadless pacemaker appears to have been the ideal device choice given the presence of complete heart block in a patient with end-stage renal disease on hemodiaysis, Staphylococcous aureus bacteremia, suspected endocarditis, and limited upper-extremity access.All reported device parameters that were observed upon implant appear to be acceptable but not ideal, and single-view X-ray suggested appropriate device positioning.A few concerning electrical parameters included an impedance of less than 800 Ω, which has been demonstrated to be an independent predictor of elevated Micra™ thresholds at 12 months, 2 and an initial threshold of 1.3 mV, which is also a predictor of elevated thresholds during follow-up. 3These suboptimal numbers, while acceptable, could imply that the Micra™ device had suboptimal tissue contact.