Conduction system pacing in a congenital heart block patient with epicardial left ventricular pacing heart failure

Conduction system pacing plays a major emerging role for electrical cardiac resynchronization in patients with heart failure with reduced ejection fraction and inter-ventricular dyssynchrony.1 Congenital atrioventricular block occurs in 2%–5% of pregnancies with positive autoantibodies (anti-Ro/SSA) affecting the cardiac conduction system. These autoantibodies tend to affect the cardiac ion channels leading to electrophysiological disturbances such as bundle branch block, corrected (QTc)interval prolongation, and sudden cardiac death. A 16-year-old girl with congenital complete heart block had an epicardial left ventricle lead (VVIR) implanted in 2008. Her echocardiogram in 2009 showed a left ventricular ejection fraction of 72%. Her mother was diagnosed as anti-Ro/SSA antibody positive. She was admitted for heart failure with New York Heart Association (NYHA) Class III in 2023. Her echocardiogram on admission showed a poor left ventricle systolic function of 15% with global hypokinesia and poor right ventricle systolic function (tricuspid annular plane systolic excursion 1.20 cm; peak systolic velocity of lateral tricuspid annulus= 4.3 cm/s) and severe tricuspid regurgitation (estimated pulmonary artery systolic pressure= 48 mmHg). Coronary angiogram showed smooth coronaries with no anomalies. A right heart study yields no evidence of intracardiac shunts or pulmonary hypertension. She had biventricular heart failure requiring optimization of heart failure medications inclusive of oral entresto, bisoprolol, and spironolactone. An Abbott Assurity MRITM 2272 dual-chamber pacemaker was implanted. The right ventricle lead (TendrilTM STS 2088TC/58 cm) was deployed and extended to the left bundle branch capturing the posterior fascicle with a left ventricle activation time (LVAT) of 75 ms and an interpeak of 60 ms. The right atrial lead helix was extended to the right atrial appendage with a P wave of >4.0 mV and good current of injury. Her native electrocardiogram showed broad left bundle branch block (LBBB) morphology, and post-conduction system implantation showed narrow complex left bundle branch capture.2 Her follow-up in device clinic at 6 months and 1 year showed remarkable improvement in her left ventricular ejection fraction from 35% to 52% respectively with improved activities of daily living to NYHA Class I. Her left ventricle end systolic volume (LVESV) showed reduction from 97.8 to 38.2 mL over the duration of 1 year post-implant demonstrating successful reverse remodelling and outcome. She was kept on the same optimal heart failure medications during the post-implant device clinic follow-up.3 Conduction system pacing is proven to be beneficial in patients with epicardial left ventricle pacing-related cardiomyopathy due to the direct activation of the left bundle branch by preventing delay in left ventricle activation. It also improves left ventricular ejection fraction and restores ventricular synchrony together with left ventricle reverse remodelling.4–6 Hence, left bundle branch pacing for physiologic activation in these congenital atrioventricular block patients with exposure to maternal anti Ro/SSA antibodies might be the preferred strategy warranting further data. (A) Dual-chamber conduction system pacing with the left bundle branch pacing lead with an old abdominal pulse generator connected to the epicardial left ventricle lead. (B) Lateral chest X-ray showing the location of the epicardial left ventricle lead at the apical left ventricle. (C) Transthoracic echocardiogram with improvement of left ventricle ejection fraction to 35% and left ventricle end-systolic volume of 97.8 mL at 6 months. (D) Transthoracic echocardiogram with improvement of left ventricle ejection fraction to 52% and left ventricle end-systolic volume of 38.2 mL at 1 year. (E) Marked improvement to mild tricuspid regurgitation severity at 1 year. (F) Broad complex QRS in keeping with RBBB pattern in Lead V1 and superior axis in Leads II, III, and aVF together with positive Leads I and aVL indicates the location of the left ventricle apical lead to be laterally apical in location leading to dyssynchrony. (G) Narrow complex QRS (100 ms) with terminal r′ in Lead V1 and qR pattern in Leads II, III, and aVF together with rS pattern in Leads I and aVL. The left ventricular activation time of 75 ms and interpeak of 60 ms in keeping with left bundle branch pacing with left posterior fascicle capture. Kunaraj Perumalu (Writing—original draft [lead], Writing—review & editing [lead]), Saravanan Krishinan (Supervision [lead]), Sotheenathan Krishinan (Supervision [lead]), and Mohamed Jahangir Abdul Wahab (Supervision [lead]) Consent: The authors confirm that written consent for submission and publication of this case report including images and associated text has been obtained from the patient in line with the COPE guidelines Funding: This research did not receive any specific grant from funding agencies in the public, commercial or not-for-profit sectors. Data available on request from the authors.