RESUMEN
INTRODUCTION: There is a lack of consensus on the definition of response to cardiac resynchronization therapy (CRT), and it is not clear which response criteria have most influence on cardiac event-free survival. OBJECTIVES: To assess the predictive value of various response criteria in patients undergoing CRT and the agreement between them. METHODS: We performed a secondary analysis of the BETTER-HF trial. Patient response was classified at six months after CRT according to eleven criteria used in previous trials. The predictive value of response criteria for survival free from mortality, cardiac transplantation and heart failure hospitalization was assessed by Cox regression analysis. Agreement between the different response criteria was assessed using Cohen's kappa (κ). RESULTS: A total of 115 patients were followed for a mean of 25 months. During follow-up, 15 deaths occurred (13%) and 29 patients had at least one adverse cardiac event (25%). Only five of the eleven response criteria were predictors of event-free survival. The most powerful isolated clinical and echocardiographic predictors were a reduction of ≥1 NYHA functional class (HR 0.39 for responders; 95% CI 0.18-0.83, p=0.014) and an increase of at least 15% in left ventricular ejection fraction (HR 0.43, 95% CI 0.20-0.90, p=0.024), respectively. Agreement between the different response criteria was poor. CONCLUSIONS: Most currently used response criteria do not predict clinical outcomes and have poor agreement. It is essential to establish a consensus on the definition of CRT response in order to standardize studies.