Detection of Leak From Left Atrial Appendage Occlusion Using Dielectric Imaging

Peri-device leak (PDL) following left atrial appendage occlusion (LAAO) may lead to an increased risk of thrombosis. However, current modalities for PDL detection, such as trans-esophageal echo (TEE) and cardiac CT do not provide quantitative measures of PDL.

to use dielectric imaging (DI) to measure PDL from a Watchman (WM) LAAO device.

A conductivity contrast agent is injected into the left atrium (LA) through the WM delivery system, while making DI measurements. Recordings are analyzed with a two-compartment model and the flow from the left atrial appendage (LAA) characterized by a "% clearance / beat" (CPB) parameter. With ethics approval, four dogs (26 ± 1.8  kg) were anesthetized and ventilated. Body-surface electrodes were placed and impedance data continuously acquired. WM devices (0-35% oversized) were introduced and placed into the LAA. During the study, the WM was either fully or partial deployed. At each deployment level, 10 mL of conductivity contrast was injected through the WM delivery sheath. At twenty-two deployment conditions, Doppler-flow TEE measurements were made, and compared to the DI-based value.

In all cases, CPB values correctly predicted the TEE-based assessment of PDL (100% sensitivity/specificity). The TEE leak size also corresponded to CPB values with a correlation of r = 0.914 (p 0.001).

Using DI signals, the leak flow from the WM LAAO can be measured and yields comparative results to TEE for detection of PDL. The DI method requires no other imaging modality or ionizing radiation and iodine contrast agent injection.