QRS duration in evaluating ventricular dyssynchrony in patients with chronic systolic heart failure

Abstract

Objective To observe the types,prevalence of cardiac dyssynchrony in patients of chronic systolic heart failure(SHF),and to investigate the value of QRS duration 135 ms in selecting patients for cardiac resynchronization therapy(CRT).Methods Forty-five patients with SHF were randomly divided into two groups according to QRS width: Group 1(QRS width 120 ms,21 patients) and Group 2(QRS width ≥120 ms,24 patients).Electrocardiography,conventional echocardiography,and tissue doppler were performed in all patients to evaluate the cardiac systolic dyssynchrony.Meanwhile,the diagnostic value of optimized QRS width to evaluate the dyssynchrony indices was tested while using 135 ms as new cutoff value.Results Systolic function: compared with Group 2,Group 1 had significantly higher LVEDD and LVEDV(P=0.03 and 0.01,respectively),lower LVEF(P=0.004),and had significantly higher NYHA class(P=0.002)and more frequent use of diuretics and digoxins(P=0.01,both).Dyssynchrony parameters: Group 2 had a significantly higher prevalence of interventricular dyssynchrony(70.8% vs 15%,P0.000 1) and higher IVMD value(P0.000 1) than Group 1;the prevalences of intraventricular dyssynchrony were high in both groups(71.4% vs 79.2%,P=0.55),except that the APET value was prolonged in Group 2.Other indices(Ts-SD,Ts-12,and SPWMD)showed no significant difference between the two groups.Correlation analysis: a strong correlation was found between QRS duration and interventricular dyssynchrony(r=0.58,P0.000 1),while it was fairly poor between QRS duration with intraventricular dyssynchrony(r=0.07,P=0.64).ROC analysis: QRS width 135 ms could finely predict the presence of interventricular dyssynchrony,with a sensitivity of 80% and a specificity of 87.5%;while the same cutoff value to predict intraventricular dyssynchrony only yielded a sensitivity of 44.1% and specificity of 73.6%.Conclusion Intraventricular dyssynchrony and(or) interventricular dyssynchrony has a high prevalence in patients with SHF.A QRS duration cutoff value higher 135 ms can well evaluate the cardiac mechanical dyssynchrony in clinical practice,which may be of value for optimizing selection of CRT candidates and reducing the nonresponders.