120 The diagnostic value of multi-modality imaging prior to first pacemaker implant in younger patients with AV block

Introduction ESC guidelines recommend multi-modality imaging be considered for patients ≤60 years with conduction disorders to identify underlying systemic diseases. Ideally this should be done prior to PPM implantation but this is often not practicable due to clinical urgency or difficulties with data acquisition due to slow/irregular heart rates. The aim of the study was to review pre-existing cardiac pathologies in this group from their past medical history/diagnostic imaging performed prior to implant and in the follow-up period. We also determined if new cardiac pathologies came to light post-implant and therefore for how many the presentation of significant AV block was the index presentation of another cardiac condition. Method We identified 142 patients from the Trust's pacing database who received a first pacemaker implant between Jan-13 and Jan-22 aged ≤60 years. We used the electronic patient notes and pacing file to clarify the patient demographics, clinical characteristics, pre-implant investigations, known pathologies, post-implant investigations and any new cardiac pathologies that developed. Follow up data was collected up to Aug-23. Results 38 patients were paced for high degree AV block during the study period. Clinical characteristics, demographic data and conditions predisposing to the development of high degree AV block are in table 1. 2 patients were diagnosed with congenital heart block. 7 patients died during follow-up (table 2). 21 patients had an echocardiogram before or during the index admission. 2 patients had abnormalities consistent with idiopathic dilated cardiomyopathy. 4 patients had a CMR prior to implant of which 2 were consistent with cardiac sarcoid. 1 of these had bilateral hilar lymphadenopathy on an earlier CT scan and a subsequent PET CT confirmed the diagnosis. The other was under respiratory for suspected pulmonary sarcoid but did not attend their PET CT. In the post-implant period 14 patients had a variety of investigations including echo, CMR, cardiac CT, PET CT and MPS. 24 patients had no additional investigations. 3 patients had a new cardiac pathology diagnosed in the post-implant period. 2 developed severe LVSD secondary to RV pacing within a year of PPM implantation. 1 new case of DCM developed during the follow up period. There were no confirmed cases of cardiac sarcoid or other systemic cardiac conditions in the post-implant monitoring period. Conclusions Younger patients who develop high degree AV block have a low prevalence of systemic cardiac pathologies in our Trust. This could reflect a low prevalence in this patient cohort or an under-diagnosis due to lower use of multimodality imaging such as CMR. A study from 2014 suggested routine FDG-PET imaging in this patient group revealed a 34% incidence of cardiac sarcoid, however this has not been reproduced in other studies. Patients were more likely to develop complications related to their pacemaker than any other kind of cardiac pathology. Conflict of Interest None