Adherence to 2016 European Society of Cardiology guidelines predicts outcome in a large real-world population of heart failure patients requiring cardiac resynchronization therapy

Background Professional guidelines are based on the best available evidence. However, patients treated in clinical practice may differ from those included in reference trials. Objective The aim of this study was to evaluate the effects of cardiac resynchronization therapy (CRT) in a large population of patients implanted with a CRT device stratified in accordance with the 2016 European heart failure (HF) guidelines. Methods We collected data on 930 consecutive patients from the Cardiac Resynchronization Therapy MOdular REgistry. The primary end point was a composite of death and HF hospitalization. Results Five hundred sixty-three (60.5%) patients met class I indications, 145 (15.6%) class IIa, 108 (11.6%) class IIb, and 114 (12.3%) class III. After a median follow-up of 1001 days, 120 patients who had an indication for CRT implantation had died and 71 had been hospitalized for HF. The time to the end point was longer in patients with a class I indication (hazard ratio 0.55; 95% confidence interval 0.39–0.76; P = .0001). After 12 months, left ventricular (LV) end-systolic volume had decreased by ≥15% in 61.5% of patients whereas in 57.5% of patients the absolute LV ejection fraction improvement was ≥5%. Adherence to class I was also associated with an absolute LV ejection fraction increase of >5% ( P = .0142) and an LV end-systolic volume decrease of ≥15% ( P = .0055). Conclusion In our population, ∼60% of patients underwent implantation according to the 2016 European HF guidelines class I indication. Adherence to class I was associated with a lower death and HF hospitalization rate and better LV reverse remodeling.