Cardiac resynchronization therapy: QRS index as a response predictor

• Main Authors: Frank Martínez López, Osmín Castañeda Chirino, Roylán Falcón Rodríguez, Jesús A. Castro Hevia, Margarita Dorantes Sánchez, Marleny Cruz Cardentey, Ana Mengana Betancourt, Alain Gutiérrez López, Joanna de Zayas Galguera, Inti R. Quiñones Milián, Michel Cabrera Ortega, Katherine de la Vega Valcárcel
• Format: Article
• Language: English
• Published: Cardiocentro Ernesto Che Guevara 2019-07-01
• Series: CorSalud
• Online Access: http://www.revcorsalud.sld.cu/index.php/cors/article/view/486

Introduction:Cardiac resynchronization therapy (CRT) is an indication in heart failure with wide QRS and severely reduced left ventricular ejection fraction. Objectives: To define the response predictors favorable to CRT. Method: An observational, descriptive, retrospective study was conducted to evaluate the QRS index (difference between the QRS width before and after implantation, divided by its value before implantation, multiplied by 100) as a predictor of favorable response to CRT. Electrocardiograms were performed before the procedure, at 6 and 12 months after implantation. The measurements were made by two independent observers, the first digital on the operating room monitor and the rest manual. Results: A total of 91 patients (mean age 61.2 years, 76% men) were included, with QRS wider than 120 ms and ejection fraction less than 35%. A favorable response was obtained in 59%. There were no significant pre-implant differences in the QRS duration between responders and non-responders (151.3 ms vs. 151.34 ms, p=0.98), but there were differences post-implant (100 vs. 115 ms, p<0.0001), as well as in the QRS percentage of decrease (33.2% vs. 24.3%, p<0.0001). The ROC curve showed that a cut-off value of the QRS index of 30% was sensitive (62%) and specific (75%) in order to predict a favorable response. Conclusions: The decrease in the QRS width after the CRT implant is related to a favorable response to it.