Use of Three-dimensional Electroanatomic Mapping for Epicardial Access: Needle Tracking, Elctrographic Characteristics and Clinical Application

Background and Aims Pericardiocentesis is usually completed under fluoroscopy. The electroanatomic mapping (EAM) system allows visualizing puncture needle tip (NT) while displaying the electrogram recorded from NT, making it possible to obtain epicardial access (EA) independent of fluoroscopy. This study was designed to establish and validate a technique by which EA is obtained under guidance of 3-dimensional (3D) EAM combined with NT electrogram. Methods 3D shell of the heart was generated and the NT was made trackable in the EAM system. Unipolar NT electrogram was continuously monitored. Penetration into pericardial sac was determined by an increase in NT potential amplitude and an injury current. A long guidewire of which the tip was also visible in the EAM system was advanced to confirm EA. Results EA was successfully obtained without complication in 13 pigs and 22 patients. In the animals, NT potential amplitude was 3.2± 1.0 mV when it was located in mediastinum, 5.2±1.6 mV when in contact with fibrous pericardium and 9.8±2.8 mV after penetrating into pericardial sac (all p≤0.001). In human subjects, it measured 1.54±0.40 mV, 3.61±1.08 mV and 7.15±2.88 mV respectively (all p<0.001). Fluoroscopy time decreased in every 4-5 cases (64±15, 23±17 and 0 second for animals 1-4, 5-8, 9-13 respectively, p=0.01; 44±23, 31±18; 4±7 seconds for patients 1-7, 8-14, 15-22 respectively, p<0.001). In 5 pigs and 7 patients, EA was obtained without X-ray exposure. Conclusions By tracking NT in the 3D EAM system and continuously monitoring the NT electrogram, it is feasible and safe to obtain EA with minimum or no fluoroscopic guidance.