Abstract 4348: Additive Value of Interventricular Mechanical Delay to Intraventricular Dyssynchrony for Predicting Response to Cardiac Resynchronization Therapy
Echocardiographic measures of dyssynchrony have typically been used individually to predict response to cardiac resynchronization therapy (CRT). Our objective was to test the hypothesis that the addition of interventricular mechanical delay (IVMD) to tissue Doppler (TDI) or speckle tracking radial strain will further improve the ability to predict ejection fraction (EF) response to CRT. We studied 103 consecutive class III-IV heart failure patients for CRT aged 64±12yrs with ejection fraction (EF) 24±7% and QRS 160±30ms (58% had ischemic disease). Dyssynchrony was assessed at baseline and response was defined as a ≥15% increase in EF 7±5months after the CRT. Longitudinal intraventricular dyssynchrony was assessed as tissue Doppler opposing wall velocity delay ≥65ms from 12-sites. Radial intraventricular dyssynchrony was assessed as speckle tracking radial strain anteroseptal to posterior wall delay≥130ms. Interventricular dyssynchrony was assessed as IMVD (difference between right and left ventricular ejection) ≥35ms. Individual measures of dyssynchrony predicted EF response to CRT with respective sensitivities and specificities as follows: Longitudinal tissue Doppler: 84% and 74%, radial speckle tracking: 85% and 72%, and IVMD: 63% and 83%. The addition of IVMD to intraventricular dyssynchrony measures improved the ability to predict EF response: 96% when both were present, and 22% when neither was present. IVMD appears to be of additive value to measures of intraventricular dyssynchrony for predicting EF response after CRT, and has potential for clinical applications.