Prediction of response to cardiac resynchronization therapy: the selection of candidates for CRT (SCART) study

Pacing Clin Electrophysiol. 2006 Dec;29 Suppl 2:S11-9. doi: 10.1111/j.1540-8159.2006.00486.x.


Background: The aim of this study was to evaluate the ability of baseline clinical and echocardiographic parameters to predict a positive response to CRT.

Methods: We analyzed 6-month data from the first 133 consecutive patients enrolled in a multicenter prospective study. These patients had symptomatic heart failure (HF) refractory to pharmacological therapy (NYHA class II-IV), left ventricular ejection fraction (LVEF) < or =35%, and prespecified electrocardiographic, echocardiographic or tissue Doppler imaging markers of left ventricular (LV) dyssynchrony.

Results: After a follow-up period of 6 months, 1 patient died and 13 were hospitalized for worsening HF. There were significant (P < 0.01) clinical, functional, and echocardiographic improvements that included: New York heart Association Class, Quality-of-Life Score, QRS duration, LVEF, LV end-diastolic and end-systolic diameter (LVESD), and severity of mitral regurgitation A positive response was documented in 90/133 (68%) patients who presented an improved clinical composite score associated to an increase in LVEF > or = 5 units. A multivariate analysis identified that a smaller LVESD (OR = 0.957, 95% CI 0.920-0.996; P = 0.030) and longer interventricular mechanical delay (IVMD) (OR = 1.017, 95% CI 1.005-1.029, P = 0.007) as independent predictors of a positive response. Receiver-operating curve analysis showed that a positive response to CRT may be predicted in patients with IVMD > 44 ms (with a sensitivity of 66% and a specificity of 55%) or with LVESD < 60 mm (with a sensitivity of 66% and a specificity of 61%).

Conclusions: Our results confirm the limited value of QRS duration in the selection of patients for CRT. A less-advanced stage of disease and echocardiographic evidence of interventricular dyssynchrony demonstrated to predict response to CRT, while intraventricular dyssynchrony did not predict response.

Publication types

  • Clinical Trial
  • Multicenter Study

MeSH terms

  • Aged
  • Cardiac Pacing, Artificial / statistics & numerical data*
  • Comorbidity
  • Female
  • Heart Failure / diagnostic imaging*
  • Heart Failure / epidemiology
  • Heart Failure / prevention & control*
  • Humans
  • Italy / epidemiology
  • Male
  • Middle Aged
  • Outcome Assessment, Health Care / methods*
  • Patient Selection*
  • Prevalence
  • Prognosis
  • Risk Assessment / methods
  • Risk Factors
  • Ultrasonography / statistics & numerical data*
  • Ventricular Dysfunction, Left / diagnostic imaging
  • Ventricular Dysfunction, Left / epidemiology
  • Ventricular Dysfunction, Left / prevention & control