Unintentional Septal Arterial Entry During Left Bundle Branch Area Pacing

Left bundle branch area pacing (LBBAP) is increasingly adopted as a physiological pacing strategy. Deep septal lead deployment, however, may occasionally result in unexpected vascular staining.

A 70-year-old woman with advanced atrioventricular block and preserved ejection fraction underwent LBBAP. During contrast injection to assess septal lead depth, unexpected opacification of the left anterior descending artery and a septal perforator branch occurred, suggesting inadvertent vascular entry. The lead was promptly repositioned more proximally, achieving optimal electrical parameters. The patient remained asymptomatic, and follow-up echocardiography confirmed preserved ventricular function without pericardial effusion or hematoma.

To our knowledge, this is the first report providing direct angiographic visualization of coronary opacification during LBBAP, highlighting the importance of septal vascular anatomy and imaging guidance.

Inadvertent vascular staining during LBBAP is rare and usually benign when promptly recognized. Angiographic contrast injection is useful to confirm lead position and detect unintended vascular entry.