Cardiac resynchronization therapy with left bundle branch area pacing in patients with a definitive diagnosis of cardiac sarcoidosis

Abstract Background Cardiac sarcoidosis (CS) is an infiltrative cardiomyopathy characterized by myocardial granulomatous inflammation, leading to conduction system abnormalities and ventricular arrhythmias. Cardiac resynchronization therapy (CRT) outcomes in CS patients are controversial. The efficacy of CRT with left bundle branch area pacing (LBBAP) in these patients has not yet been elucidated. Objective To evaluate electrocardiographic, echocardiographic and long-term clinical outcomes after CRT with LBBAP in CS patients. Methods In this retrospective multicenter study, conducted between June 2020 and March 2024, patients with a histopathologically confirmed diagnosis of CS with an indication for CRT were included in the analysis. The primary outcome was a composite of all-cause mortality, heart failure related hospitalizations, implantable cardioverter defibrillator shocks and requirement of left ventricular assist device/heart transplant. The primary safety outcome was procedure-related complications. Secondary outcomes included pre- and post-procedural electrocardiographic and echocardiographic parameters and change in NYHA functional class. Results A total of 16 patients were included in the analysis (mean age 66.2 ± 9.4 years; 62.5% female; body mass index 30.4 ± 8.5 kg/m2). Four patients (25%) had isolated CS. The median follow-up was 579 [Q1: 295.5 – Q3: 797.5] days. Five patients (31.25%) experienced the composite outcome. Among these, two patients (12.5%) had acute heart failure related hospitalizations, two patients (12.5%) died due to severe pulmonary hypertension and sepsis complicated by cardiorenal syndrome, respectively; and one patient (6.25%) presented an episode of ventricular tachycardia that was successfully terminated with an implantable cardioverter defibrillator shock. No patients required advanced heart failure therapies. There were no procedure-related complications. There was a significant improvement in paced QRS duration (Pre 156.8 ± 36.2 vs. Post 128.3 ± 22.3 milliseconds, p=0.003), left ventricular ejection fraction (Pre 36.5 ± 10.6% vs. Post 50.4 ± 12.2%, p<0.001), left ventricular end systolic diameter (Pre 52 [39.5 – 84.3] vs. Post 41 [29 – 72] millimeters, p=0.011) and left ventricular end diastolic diameter (Pre 66.7 [48 – 159] vs. Post 61 [44 – 135] millimeters, p=0.023). Ten (62.5%) patients exhibited an improvement ≥ I in NYHA functional class post procedure. Conclusion In CS patients, CRT with LBBAP was associated with significant improvements in electrocardiographic and echocardiographic parameters, as well as NYHA functional class, alongside favorable long-term clinical outcomes by optimizing interventricular dyssynchrony.Graphical abstract ECG and Echo parameters