Beyond a mirror-image procedure: a case report of leadless pacemaker implantation in dextrocardia with situs inversus

Dextrocardia with situs inversus (DC + SI) is a rare congenital anomaly characterized by mirror-image positioning of the heart and thoracoabdominal organs. Leadless pacemaker (LP) implantation in patients with DC + SI presents unique anatomical and technical challenges, and clinical experience remains limited.

A 76-year-old woman with DC + SI presented with tachycardia-bradycardia syndrome. Given her symptomatic bradycardia, we undertook LP implantation (Micra, Medtronic, Minneapolis, MN, USA). Pre-procedural computed tomography demonstrated a mirror-image arrangement of the thoracoabdominal organs including the heart in the right hemithorax, establishing the diagnosis of DC + SI. During implantation, conventional mirror-image catheter manipulation-counterclockwise rotation mirroring clockwise rotation in normal anatomy-caused the catheter tip to deflect towards the right ventricular free wall, due to the pre-shaped curvature of the Micra delivery catheter. Additional counterclockwise torque was required to redirect the tip towards the septum for successful deployment. The procedure was completed without complications, and the patient remained asymptomatic with stable device parameters at the 1-year post-implantation.

This case highlights how the pre-shaped curvature of the Micra delivery catheter introduces procedural complexity beyond a simple mirror-image manipulation. Additional counterclockwise torque is often required to achieve septal positioning. Comprehensive pre-procedural imaging and an understanding of the device-specific characteristics are essential for successful LP implantation in these anatomically reversed cases.