Real-world clinical outcomes after cardiac resynchronization therapy in cardiac sarcoidosis.

Cardiac sarcoidosis (CS) is an inflammatory/granulomatous disease that affects the heart and is responsible for mortality due to fatal arrhythmias or systolic heart failure. The efficacy and outcomes of cardiac resynchronization therapy (CRT) for CS remain uncertain. We retrospectively analyzed a cohort of 108 patients diagnosed with CS at Nippon Medical School Hospital and extracted 19 patients who underwent CRT implantation between 2007 and 2024 (68% female, mean age 70 ± 8 years). The mean follow-up period was 6.7 ± 4.3 years. Of 19 patients with CRT devices (2 CRT-Ps and 17 CRT-Ds), 5 patients were upgraded from pacemakers and 5 from ICDs. At 6 months after device implantation, QRS duration shortened (172 ± 34 vs. 128 ± 27ms, p < 0.001), NYHA (2.6 ± 0.8 vs. 2.1 ± 1.0, p = 0.037) improved, and BiV pacing percentage was 98 ± 2%. However, LVESV (147 ± 74 vs. 155 ± 70 ml, p = 0.878) and LVEF (28 ± 9 vs. 28 ± 11%, p = 0.452) did not improve. During the follow-up period, 8 hospitalizations due to heart failure, 2 appropriate ICD shocks, and 6 deaths due to progressive heart failure were observed. Device-related complications developed in 4 patients. In this small retrospective cohort of patients with advanced cardiac sarcoidosis undergoing CRT implantation, echocardiographic reverse remodeling was limited despite improvements in QRS duration and NYHA functional class. Clinical outcomes remained poor, likely reflecting the advanced and heterogeneous nature of the underlying disease. Further comparative studies are warranted.