[Echocardiography in cardiac resynchronization therapy: identification of suitable patients, follow-up and therapy optimization].

Cardiac resynchronization therapy (CRT) with biventricular stimulation is a new therapeutic option for patients with advanced heart failure and left ventricular asynchrony. The presence of a left bundle branch block morphology in the electrocardiogram is presently the most important selection criterion. Transthoracic echocardiography provides important additional information on the ventricular contraction sequence and the hemodynamic consequences of asynchrony. This may help to identify suitable patients, to improve the selection criteria and to optimize CRT during follow-up. This article discusses the potential techniques and limitations and provides practical guidance for the individual patient follow-up.