SVC Mapping Using an Ultra-High Resolution 3-Dimensional Mapping System in Patients With and Without AF

Area of Science:

• Cardiology
• Electrophysiology
• Anatomy

Background:

• Previous studies on human SVC myocardial extensions used autopsied hearts.
• Limited in-vivo data exists on SVC sleeve morphology and electrical properties.

Purpose of the Study:

• To characterize the superior vena cava (SVC) sleeve in patients with and without atrial fibrillation (AF).
• To investigate differences in SVC sleeve electrical properties between AF and non-AF patients.

Main Methods:

• Ultra-high-resolution mapping of the SVC in 64 patients (34 with AF, 30 without AF) during sinus rhythm.
• SVC isolation performed in 18 AF patients, followed by repeat mapping.
• Analysis of SVC sleeve length, conduction time, and pre-existing conduction block.

Main Results:

• The SVC sleeve exhibited asymmetric length, varying by SVC segment.
• Conduction time within the SVC sleeve was significantly longer in AF patients (76.1 ms vs. 61.0 ms).
• Pre-existing conduction block in the SVC sleeve was more frequent in AF patients (3/34 vs. 0/30).

Conclusions:

• Ultra-high-resolution SVC mapping reveals asymmetric musculature and patient-specific sleeve variations.
• Conduction disturbances in the SVC sleeve are more pronounced in patients with atrial fibrillation.
• These findings may have implications for understanding AF mechanisms and guiding ablation strategies.