A dedicated radiofrequency microcatheter assembly for trans-right atrial appendage pericardial carbon dioxide...

Trans-right atrial appendage (RAA) pericardial insufflation of carbon dioxide can improve safety of percutaneous epicardial access. Dedicated device solutions for safe, effective, and standardized microperforation are needed.

We evaluated the efficacy and safety of a novel radiofrequency (RF)-powered microcatheter specifically designed to facilitate trans-RAA exit to the pericardial space.

Four healthy swine underwent repeated RAA and left atrial appendage (LAA) perforations to access the pericardial space by a dedicated 1.8F microcatheter with an RF tip. Perforations were obtained by delivering short bursts of RF energy (20-25 W, <1 second, "cut" mode). Animals were sacrificed immediately after the experiment, and the hearts were assessed by gross pathologic and histologic examination.

A median number of 7 microperforations/animal (interquartile range, 7-9) were performed in the RAA and 3/animal (interquartile range, 2-3) in the LAA. In 1 animal, a posterolateral right atrial perforation was also performed. All perforations and microcatheter advancements in the pericardial space were successful (<5 seconds). There was no evidence of pericardial effusion by intracardiac echocardiography and no hemodynamic changes with any of the perforations. On pathologic examination, no pericardial effusion was noted, and the atrial perforations could be identified as punctate red areas (0.5-1 mm) in 28 of 31 targeted RAA sites and 5 of 8 targeted LAA sites. Histologic evaluation showed central full-thickness defects with associated acute thrombus formation and surrounded by a small rim of contraction band necrosis.

In this preclinical study, repeated trans-RAA/LAA perforations with pericardial space access were successfully obtained with a dedicated RF-tip 1.8F microcatheter with no evidence of significant pericardial bleeding.