Myocardial contractile function in the region of the left ventricular pacing lead predicts the response to cardiac resynchronization therapy assessed by two-dimensional speckle tracking echocardiography.

Background: The aim of this study was to test the impact of posterolateral myocardial systolic function on response to cardiac resynchronization therapy (CRT).

Methods: Forty patients were studied before and 4 +/- 2 months after CRT. Dyssynchrony was defined as anteroseptal wall-to-posterior wall delay (> or = 130 ms) caused by speckle-tracking radial strain. The average longitudinal strain in 4 posterior and lateral segments (epsilon-pl) in which the left ventricular pacing lead was positioned was calculated by automated functional imaging. Response to CRT was defined as a > or = 15% decrease in end-systolic volume.

Results: The negative value of epsilon-pl in responders was significantly higher than that in nonresponders at baseline (-7.8 +/- 6.9% vs -2.1 +/- 4.9%, P < .01). Combining dyssynchrony with epsilon-pl < -7.8% was more effective for predicting response to CRT than dyssynchrony parameters alone (92% vs 75%).

Conclusions: The addition of posterolateral myocardial systolic function to the measurement of dyssynchrony appears to be of value for predicting response to CRT.