Beating the clock: the impact of heart failure duration on CRT efficacy

Abstract Background Cardiac Resynchronization Therapy (CRT) stands as an established intervention for selected patients with heart failure (HF) presenting with a wide QRS complex. The optimal timing for CRT implantation remains uncertain. Current evidence suggests superior outcomes post-CRT in patients who have not been previously hospitalised for HF and those receiving the implant during their initial hospitalisation for HF.1 Purpose The primary objective of this study is to investigate the long-term clinical outcomes following CRT implantation relative to the duration of HF previous to the implant. It was analysed in a cohort of consecutive patients from a HF Unit who met the criteria for CRT as recommended by the ESC guidelines (QRS duration ≥150ms, left bundle branch block morphology, and left ventricular ejection fraction (LVEF) ≤35% despite optimal medical therapy). Methods We evaluated all patients who received CRT from January 2011 through September 2022. Follow-up ended in September 2023. Patients with CRT indicated for ventricular pacing due to high-degree atrioventricular block were excluded. Patients were categorized into two groups based on the duration of HF progression prior to CRT implantation: more than 3 years and 3 years or less. The primary outcome was all-cause mortality (ACM). Secondary outcomes included a composite of ACM and HF hospitalisation and the proportion of patients who demonstrated a significant improvement in LVEF (defined as an increase of ≥10% from baseline and a subsequent measurement of LVEF ≥40%). Results The cohort consisted of 127 patients, mean age 65.8±10.7 years, 23.6% were women, mean LVEF was 28.4±8.6% and 36.2% had ischaemic aetiology (Table 1). 62 patients either died or were hospitalized for HF. Mean follow-up was 4.9±2.7 years. After adjusting for age, sex and baseline LVEF, patients with HF for more than three years before CRT implantation had a worse prognosis: HRs of 2.31 for ACM (p=0.016) and 2.13 for the combined endpoint of ACM+HFH (p=0.010) (Figure 1). The proportion of patients with improved LVEF after CRT was significantly higher in the group with shorter HF duration (68.25%) compared to the group with longer HF duration (25%), p <0.001. Conclusions Our findings reveal that patients with a shorter history of HF (less than three years) prior to CRT implantation exhibit significantly better clinical outcomes. These results highlight the role of early intervention with CRT in patients with HF, suggesting that shorter HF duration prior to CRT may lead to more favourable long-term outcomes.