Abstract 12870: Transesophageal Echocardiography to Guide Correct Implantation Site of the Leadless Pacemaker

Abstract

Introduction: MICRA™ (Medtronic USA) leadless pacemakers are used to avoid complications common to conventional pacemakers, but there is still a 4% risk of complications (e.g., cardiac perforation, tamponade, and embolization). Septal device implantation may decrease risk, but helpful cardiac landmarks (e.g., tricuspid valve, pulmonary valve (PV)) are not seen under fluoroscopy. There is little guidance regarding alternative intra-procedural (IP) imaging. We studied the spatial relationship of the MICRA™ to cardiac landmarks via transesophageal echocardiography (TEE) and transthoracic echocardiography (TTE). Methods: Our prospective observational study included 23 patients undergoing MICRA™ implantation with TEE ( Table 1) . Interventricular septal placement was confirmed by fluoroscopy, electrocardiography (ECG) and TEE. Distances between the device and cardiac landmarks were measured by TTE and TEE and analyzed with ECG parameters during pacing ( Fig 1A, Fig 1B ). Results: Septal positioning of the device was achieved in all patients. TEE transgastric (0-20/90-110°) and lower mid-esophageal (40-60/130-150° with biplane) views best visualized device position. The aortic valve (AV) in the TTE apical 5 chamber view was used as a surrogate for RV apex to PV distance. With appropriate septal deployment, QRS morphology showed earlier R wave transition and 44% increased QRS width ( Table 1 ). Conclusions: TEE can guide appropriate leadless pacemaker septal implantation, and correlates with QRS pacing morphology. Further studies are required to establish reference ranges of distances from the device to cardiac landmarks to prove optimal device deployment.