Outcomes of cardiac resynchronization therapy (CRT) in cardiac sarcoidosis patients with a range of ejection fractions.

Aims: In cardiac sarcoidosis (CS) patients, the benefit of cardiac resynchronization therapy (CRT) remains unclear. We sought to assess the short-term and long-term effects of CRT in CS patients with a range of left ventricular (LV) ejection fractions (LVEFs).

Methods: Consecutive CS patients with heart failure with reduced ejection fraction (HFrEF; LVEF ≤ 40%), mildly reduced ejection fraction (HFmrEF; LVEF 41%-49%) and preserved ejection fraction (HFpEF; LVEF ≥ 50) treated with CRT under the care of a tertiary UK centre between 2008 and 2023 were reviewed. CRT response was defined by >5% improvement in serial LVEF. The primary endpoint was a composite of all-cause mortality, cardiac transplantation or unplanned hospitalization for decompensated heart failure. The secondary endpoint included ventricular arrhythmic events.

Results: Of the 100 patients enrolled (age 58 ± 10 years; 71% male), 63 had HFrEF, 17 had HFmrEF and 20 had HFpEF. After short-term follow-up (9.8 ± 5.4 months), HFrEF patients demonstrated significant LVEF response (P < 0.01). On Kaplan-Meier analysis (follow-up 38 ± 32 months), HFrEF non-responders had significantly worse event-free survival compared with HFrEF responders for the primary (P < 0.001) and secondary (P = 0.001) endpoints. Despite short-term LV function improvement, CRT responders still had worse event-free survival compared with HFmrEF/HFpEF patients for the primary endpoint (P < 0.001). On multivariable Cox analysis, age [hazard ratio (HR) 1.05, 95% confidence interval (CI) 1.01-1.10, P = 0.008] and HFrEF CRT non-response (HR 12.33, 95% CI 2.45-61.87, P = 0.002) were associated with the primary endpoint.

Conclusions: In CS patients with HFrEF, CRT response is associated with a better long-term prognosis than non-response. However, HFrEF CRT responders still have worse long-term prognosis than HFmrEF/HFpEF patients.