Kardiale Resynchronisation -wie viel mechanische Dyssynchronie und wie viel Bildgebung ist im Vorfeld notwendig?

Cardiac resynchroinsation therapy (CRT) aims to correct the mechanicaldyssynchrony in patients with heart failure and broad QRS complex.Until now, indication for CRT is based mainly on clinical and electrocardiographiccriteria. Because QRS width is only weakly correlated to mechanicaldyssynchrony, imaging techniques such as echocardiography and magneticresonance tomography (MRT) seem suitable for analysis of dyssynchrony.Echocardiography has been studied in several studies for identificationof suitable CRT candidates. Apart from conventional methods suchas M mode-, 2 D-, and Doppler echocardiography other techniques whichwill be discussed in this article, including tissue Doppler echocardiography,have been used. Despite many positive results in individual studiesno single echocardiographic parameter was able to predict positiveCRT response in a prospective multicenter trial. Thus, QRS widthremains the ”gold standard” for CRT patient identificationat present. In borderline cases, a combination of several echocardiographicmeasures of dyssynchrony may prove helpful. The results of studieswith new techniques such as 2-dimensional strain analysis or 3D-echocardiographyremain to be awaited. In the future, MRT may play a bigger rolein this setting.