Associations between cardiac resynchronization therapy and clinical outcomes according to the atrial fibrillation status in patients with heart failure with reduced ejection fraction

Aims To evaluate in patients with heart failure with reduced ejection fraction (HFrEF) the association between patient characteristics and likelihood of receiving cardiac resynchronization therapy (CRT), as well as between CRT and clinical outcomes, according to comorbid atrial fibrillation (AF). Methods and results Patients in the Swedish Heart Failure (HF) Registry who met the guidelines’ recommendation for CRT between 2014 and 2022 were included. The primary endpoint was the composite of time to first HF hospitalization or cardiovascular (CV) death. Secondary endpoints were its individual components, all-cause death, and the total number of HF hospitalizations. Out of 3530 patients with HFrEF and an indication for CRT, 24.7% received a CRT. A history of or concomitant AF were observed in 51.6% of patients. AF was not associated with the likelihood of receiving a CRT, and the patient characteristics independently associated with CRT were consistent regardless of AF, except for CRT being less likely implanted in patients with valvular disease without AF, and more likely among those with AF and university (vs. compulsory) education. Regardless of AF, CRT use was associated with a lower adjusted risk of CV death/first HF hospitalization [hazard ratio (HR): 0.71, 95% confidence interval (CI) 0.64–0.79], of its individual components, and of all-cause death (HR: 0.72, 95% CI 0.64–0.81), but not with total number of HF hospitalizations. Conclusion A diagnosis of AF was not associated with the likelihood of receiving CRT in real-world HF care, nor did it affect the association between CRT and lower risk of clinical outcomes.