Rick Schreurs

99 SonR for AV-optimization experiments need to be extrapolated with care to the clinical situation. Importantly also, acute hemodynamic improvements may not (fully) translate into clinical improvements. However, the positive results of the CLEAR and RESPOND-CRT trials are promising in this respect. CONCLUSIONS The SonR1 amplitude is a complex parameter that is influenced by changes in cardiac contractility and AV-delay dependent alterations of transmitral flow. Although the SonR algorithm is an effective way of optimizing AV and VV-delay in patients receiving CRT, the pathophysiology of the SonR1 signal needs further unravelling in order to optimize the algorithm. 5