Leadless pacemaker implantation during pregnancy: Quantitative assessment of fetal radiation exposure

Leadless pacemakers offer an alternative to conventional pacing by eliminating lead- and pocket-related complications. However, their use during pregnancy remains very limited because of concerns related to radiation exposure. We describe the clinical experience of a 17-week pregnant patient who presented with episodes of dizziness, profound weakness, and syncope. Further evaluation revealed second-degree atrioventricular block, Mobitz type II, and transient third-degree atrioventricular block documented by Holter monitoring, indicating the need for permanent pacing. The patient underwent implantation of a Micra AV (Medtronic, USA) leadless pacemaker under fluoroscopic guidance using optimized radiation safety protocols. The estimated fetal absorbed dose was 1.4 mGy, well below reported thresholds for deterministic effects and associated with a very low additional radiation risk compared with background risks of congenital malformations and childhood cancer. The maternal effective dose was 15 mSv. Post-procedure follow-up demonstrated complete symptom resolution, an uncomplicated continuation of pregnancy, and delivery of a healthy infant. This case illustrates the practical feasibility of leadless pacemaker implantation during pregnancy when careful radiation minimization strategies are applied and adds real-world experience to the limited data available for critical pacing indications in pregnant patients.