A novel technique for vein of Marshall blood sampling and its application in assessing atrial remodeling in atrial fibrillation.

BACKGROUND

Atrial fibrillation (AF) involves structural and autonomic remodeling, yet direct biochemical assessment of the atrial microenvironment remains challenging due to limited access to atrial tissue.

OBJECTIVE

To develop and validate a novel catheter-based technique for selectively sampling blood from the vein of Marshall (VOM), and to assess its utility in capturing atrial-specific molecular signals relevant to AF pathophysiology.

METHODS

In 22 patients undergoing catheter ablation for AF, we collected blood from the VOM, anterior interventricular vein (AIV), coronary sinus (CS), and left atrial (LA) cavity using a fluoroscopy-guided over-the-wire balloon catheter approach. Atrial natriuretic peptide (ANP) and norepinephrine (NE) concentrations were measured by ELISA.

RESULTS

VOM blood exhibited significantly higher levels of ANP and NE compared to AIV and CS samples (p < 0.0001), indicating atrial-enriched biochemical content. ANP levels in the VOM were significantly elevated in patients with persistent versus paroxysmal AF (p = 0.0055) and correlated with left atrial diameter (r = 0.45, p = 0.036), suggesting a link to structural remodeling. While NE levels did not differ by AF subtype, the trans-atrial NE gradient (VOM-LA) was significantly higher in persistent AF (p < 0.05), suggesting localized sympathetic activation.

CONCLUSIONS

This study introduces a feasible and reproducible method for real-time biochemical profiling of the human atrium. VOM-derived blood provides a unique window into atrial remodeling, with ANP and NE offering complementary insights into structural and autonomic substrates of AF. This technique may serve as a platform for future mechanistic studies and biomarker discovery.