Assessing the position of pacemaker leads via transthoracic echocardiography: a prospective study

Abstract Funding Acknowledgements Type of funding sources: None. BACKGROUND/ INTRODUCTION Lead-induced tricuspid regurgitation (TR) in patients with cardiac implantable electronic devices (CIED) is associated with increased morbidity and mortality. Mechanisms proposed to explain CIED-induced TR can be classified as primary (implantation-related, lead-related) and secondary (pacing related). Primary CIED-induced TR results from the direct interaction of the lead with the tricuspid valve (TV). Determination of exact lead position via echocardiography is crucial however often difficult via standard views. Previous research has shown the value of an atypical subcostal 2D en-face view to describe the exact anatomy of the TV (Figure 1) (1-3). PURPOSE In this prospective observational investigation, we aimed to demonstrate the feasibility of the subcostal 2D en-face view of the TV to determine RV lead position at the level of TV passage and thereby to unmask potentially unfavorable lead-positions and interactions with the TV, which might otherwise remain unnoted. METHODS Consecutive patients who underwent implantation of CIED with at least one RV lead were prospectively included. Comprehensive transthoracic echocardiography (TTE) was performed before and after the procedure. An en-face view of the TV by an approximately 90° counter-clockwise rotation of the transducer from a standard subcostal 4-chamber view was attempted in all patients. Exact lead-position (e.g. postero-septal commissural, central, etc., see Figure 1) was described whenever possible. RESULTS A total of  35 patients were included in the final analysis, median age was 62 years, 27/35 (77%) were male. Thirteen patients (37%) already had an RV lead prior to the recent procedure and therefore showed 2 or more leads passing the TV in post-procedural controls. Implanted devices included cardiac contractility modulation (CCM) (7/35 patients, 20%), implantable cardioverter-defibrillator (ICD) (11/35 patients, 31%), cardiac resynchronization therapy (CRT) (7/35 patients 20%) and pacemaker (PM) (7/35 patients, 20%). Three patients (9%) received an additional RV lead due to RV lead dysfunction. The exact position of the RV lead could be determined applying the en-face view in 27/35 patients (77%). In the majority of cases (20/35 patients, 57%), the RV lead passed through the tricuspid plane in a postero-septal commissural position. Central trajectory was observed in 5/35 patients (14%). Anteroseptal and anteroposterior passage were each found in one patient. In the remaining 8/35 patients (23%), lead position could not be determined due to inferior image quality from the subcostal view. CONCLUSIONS RV lead position can be determined from a subcostal en-face view of the TV in a majority of patients after CIED implantation. Hereby, 2D-TTE can add significant value to the management, follow-up, and monitoring and should therefore be included in the standard TTE protocol of every patient with CIED. Abstract Figure 1