Aims: Current imaging techniques attempt to identify responders to cardiac resynchronization therapy (CRT). However, because CRT response may depend upon several factors, it may be clinically more useful to identify patients for whom CRT would not be beneficial even under optimal conditions. We aimed to determine the negative predictive value of a composite echocardiographic index evaluating atrial-ventricular dyssynchrony (AV-DYS) and intraventricular dyssynchrony.
Methods and results: Subjects with standard indications for CRT underwent echo before and during the month following device implantation. AV-DYS was defined as a percentage of left ventricular (LV) filling time over the cardiac cycle. AV-DYS, which produces a characteristic rocking of the LV apex, was quantified as the percentage of the cardiac cycle over which tissue Doppler-derived displacement curves of the septal and lateral walls showed discordance. CRT responder status was determined based on the early haemodynamic response to CRT (intra-individual improvement >25% in the Doppler-derived LV dP/dt). Among 40 patients, optimal cut-points predicting CRT response were 31% for LV apical rocking and 39% for AV-DYS. The presence of either apical rocking >31% or AV-DYS ≤ 39% had a sensitivity of 95%, specificity of 80%, positive predictive value of 83%, and a negative predictive value of 94% for CRT response.
Conclusion: After pre-selection of candidates for CRT by QRS duration, application of a simple composite echocardiographic index may exclude patients who would be non-responders to CRT and thus improve the global rate of therapy success.