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To evaluate potential parameters related with super-response to CRT.
60 CRT patients (mean age 54.3±9.8 years; 80% men) with congestive heart failure (CHF) II-IV NYHA functional class were enrolled. At baseline, 1 month, 3 months and each 6 months after implantation clinical, electrocardiographic and echocardiographic parameters, NT-proBNP level were evaluated. According to the best decrease of left ventricular end-systolic volume (LVESV) (mean follow-up period 33.7±15.1 months) patients were classified as super-responders (SR) (n=28; reduction in LVESV ≥30%) and non-SR (n=32; reduction in LVESV <30%).
At baseline groups differed in age (58.1±5.8 years in SR vs 50.8±11.4 years in non-SR; p=0.003), gender (female gender 32.1% vs 9.4% respectively; p=0.028), width of QRS complex (157.6±40.6 ms in SR vs 137.6±33.9 ms in non-SR; p=0.044). Percentage of LBBB was equal between groups (75% in SR vs 59.4% in non-SR; p=0.274). All parameters of mechanical dyssynchrony were higher in SR, but only difference in left ventricular pre-ejection period (LVPEP) was statistically significant (153.0±35.9 ms vs 129.3±28.7 ms p=0.032). NT-proBNP level was lower in SR (1581±1369 pg/ml vs 3024±2431 pg/ml; p=0.006).
The survival rates were 100% in SR and 90.6% in non-SR (log-rank test P=0.002). Multiple logistic regression analysis showed that LVPEP (HR 1.024; 95% CI 1.004–1.044; P = 0.017), baseline NT-proBNP level (HR 0.628; 95% CI 0.414–0.953; P=0.029) and age at baseline (HR 1.094; 95% CI 1.009-1.168; P=0.30) were independent predictors for CRT super-response. ROC curve analysis demonstrated sensitivity 71.9% and specificity 82.1% (AUC=0.827; p<0.001) of this model in prediction of super-response to CRT.
Super-response to CRT is associated with better survival in long-term period. Presence of LBBB was not associated with super-response. LVPEP, NT-proBNP level and age at baseline can be used as independent predictors of CRT super-response.