Relationship between pre-implant ejection fraction and outcome after cardiac resynchronization therapy in symptomatic patients

Background Left-ventricular ejection fraction (LVEF) is regarded as a strong predictor for morbidity and mortality in heart failure patients. The aim of the analysis was to assess the relationship between pre-implant LVEF and outcome of patients with advanced heart failure who received cardiac resynchronization therapy (CRT). Methods We analysed the two-year follow-up of 366 patients who had been enrolled in the MASCOT study which included NYHA class III/IV patients with a class I CRT indication. Pre-implant LVEF was stratified by tertile. Results The boundaries for pre-implant LVEF were < 22% (n = 128; 18.2 +/- 3.1%; T-low), 22% to 28% (n= 121; 25.4 +/- 1.4%; T-middle) and > 28% (n = 117; 32.6 +/- 3.9%;T-high) for each tertile. Two-year post-implant LVEF was 32.0 +/- 11.5% (T-low), 33.7 +/- 10.8% (T-middle) and 36.4 +/- 9.9% (T-high).T-low had a greater increase between pre- and post-implant LVEF compared to T-middle (P= 0.03) and T-high (P = 0.0001). NYHA class improved similarly among the three groups as well as the quality of life score. No significant differences were detected between the three groups for all-cause mortality, cardiac death, all-cause hospitalization, and hospitalization due to worsening heart failure. Conclusions Symptomatic heart failure patients with a wide QRS complex and a severe impaired LV function had a better improvement of their pre-implant LVEF than patients with a more preserved LVEF. This may be one reason that in these patient groups long-term morbidity and mortality were not related to their pre-implant LVEF. Pre-implant LVEF was in symptomatic CRT patients not predictive for their long-term cardiovascular morbidity and mortality.