Associazione Nazionale Medici Cardiologi Ospedalieri




Madaudo Cristina Palermo(Palermo) – University Hospital Paolo Giaccone, Operative Unit of Cardiology – UTIC & EP Lab, Palermo, Italy | Coppola Giusepe Palermo(Palermo) – University Hospital Paolo Giaccone, Operative Unit of Cardiology – UTIC & EP Lab, Palermo, Italy | Mascioli Giosuè Desenzano del Garda(Brescia) – Garda Regional Social-Healthcare Institution, Operative Unit of Cardiology – UTIC, Desenzano Del Garda, Italy

BACKGROUND: Several studies have evaluated the role of QRS duration (QRSd) or QRS narrowing as a predictor of response to cardiac resynchronization therapy (CRT) to reduce non-responders.

PURPOSE: The aim of our study was to determine the correlation between the relative change in QRS narrowing index (QI) compared to clinical outcome and prognosis in patients who underwent CRT implantation.
METHODS: A three-center study involving 398 patients with a CRT device was conducted. Clinical variables, echocardiographic parameters and drug therapies, QRS duration before and after CRT implantation, and QRS index (QI) were measured.

RESULTS: In a six-month follow-up, a significant improvement in left ventricle ejection fraction (EF), left ventricle end-diastolic and systolic volumes (LVEDV and LVESV) were observed. QI was significantly related to reverse remodelling (r = + 0.22; 95% CI: 0.11 to 0.32, p= 0.001) and the cut-off value that best predicted LV reverse remodelling was 12.25% (AUC 0.7, p=0.001). At 24 months, a statistically significant difference was found between patients with a QI < 12.25% and those with a QI > 12.25%, regarding NYHA class worsening (p= 0,04). The mean of the QI of patients who died from cardiovascular causes was lower than patients who died of other causes (p=0,0179). A correlation between pre-CRT QRSd/LVEDV and QI was observed (r = + 0.20; 95% CI: 0.09 to 0.30, p=0.0003). A higher QRSd/LVEDV ratio was associated with an improved LVEF, LVEDV, LVESV (p <0.0001) at follow-up. CONCLUSIONS: QI narrowing after CRT was related to greater echocardiographic reverse remodelling and lower rate of adverse events. The QI can improve adverse events' prediction in a population with CRT regardless of comorbidities according to the Charlson Comorbidity index. QI could be used to predict CRT response.