Author(s): Pinto, Maria Rita da Silva Alexandre
Date: 2012
Persistent ID: http://hdl.handle.net/10400.5/5473
Origin: Repositório da UTL
Subject(s): Cardiac resynchronization therapy; Cardiopulmonary exercise testing; Exercise capacity; Heart failure; Heart rate response; Oxigen uptake; Prognosis; Responders; Slope of the ventilatory response; Ventilatory threshold
Mestrado em Exercício e Saúde
Background: Cardiac resynchronization therapy (CRT) is an established treatment modality for moderate to severe heart failure (HF) but 30–40% of patients treated with CRT do not experience clinical improvement. Purpose: the aim of this study was to identify predictors of response to CRT, in two different definitions of responders, by using the cardiopulmonary exercise testing (CPET) before CRT implantation. In definition A, responders were defined as ≥15% improvement in left ventricular ejection fraction (LVEF); in definition B combined parameters were defined as ≥5% improvement in LVEF and ≤1 level NYHA classification. Methods: this is a prospective observational study of 15 HF patients undergoing CRT. Clinical CPET and echocardiography assessment using standard methods were performed at baseline and 5 months. Results: the number of patients classified as responders in definition A was 9 (60%) and 6 (40%) as non-responders; the number of responders in definition B was 11 (73.3%) and 4 (26.7%) as non-responders at 5 months after CRT. The responders according to definition A did not present any statistically significant difference. According to definition B, the heart rate (HR) response during CPET was higher in non-responders: HR peak (157±13bpm vs. 118±18bpm, p<0.05) and HR recovery at minute 3 (54±13bpm vs. 31 ± 14bpm, p<0.05). Overall, the responders were older (68±9years vs. 55±9years, p<0.05). Conclusions: baseline measurements of CPET may be utilized to identify patients that benefit from CRT. The use of combined criteria is a better predictor than LVEF alone.
