B-PO05-159 CLINICAL PROFILE OF YOUNG PATIENTS WITH ATRIOVENTRICULAR CONDUCTION BLOCKS REQUIRING PERMANENT PACING

Abstract

Atrioventricular (AV) conduction blocks are uncommon at a young age, most common causes being congenital or genetic. Other causes include inflammatory cardiomyopathies (IC) which can infiltrate the His-Purkinje system leading to AV blocks. The clinical profile of this group of patients has not been described previously. To describe the clinical and imaging profile of young patients with AV blocks and IC. We included young (<60 years) patients presenting with AV blocks (requiring permanent pacing) between August 2019 and December 2020. All patients underwent clinical evaluation, transthoracic echocardiography, and positron emission tomography computed tomography (PET-CT) of the chest to look for associated IC. Patients with mediastinal lymphadenopathy underwent transbronchial lymph node biopsy for histopathological confirmation of IC. Patients were categorized into clinical cardiac sarcoidosis (CS), isolated CS, or nonspecific IC based on the 2016 Japanese Circulation Society guidelines (JCS). A total of 21 patients were included in the study with a mean age of 40.4±12.4 years with a male predominance (M:F=2:1). Complete AV block was the commonest type of AV block (85.7%), with a mean ventricular escape rate of 39.7±11 bpm and a wide QRS morphology in 66% of the patients. Five of the patients (23.8%) had left ventricular systolic dysfunction. The mean left ventricular ejection fraction was 53.1±10.9%. Ten (47.6%) patients showed a combination of metabolic and perfusion defect on PET CT whereas seven (33.3%) patients had mediastinal lymphadenopathy. Four patients (19.1%) underwent transbronchial lymph node biopsy, of which only one (4.8%) had granulomatous lymphadenitis. After complete evaluation, the most common classification was nonspecific inflammatory cardiomyopathy in 13 (61.9%) patients, followed by isolated cardiac sarcoidosis in seven (33.3%) patients, and one patient (4.8%) had clinical cardiac sarcoidosis. Patients presenting with AV blocks at a young age (<60 years) should be evaluated for inflammatory cardiomyopathy, even with normal LVEF. They can be considered for appropriate anti-inflammatory medications for the underlying cardiomyopathy.