Cardiac resynchronisation therapy

Cardiac resynchronisation therapy (CRT) is used to treat heart failure when there is also a left bundle branch block present. Having a LBBB and heart failure worsens the heart failure because of the desynchronised contraction of the right and the left ventricle. The CRT device is a specialised pacemaker which ensures that the two ventricles contract synchronously.

There exist CRT devices with ICD functionality as well, called CRT-D devices. These are useful because some patients with an indication for CRT also have indication for ICD, and the same patient can’t have two devices.

Unfortunately, not all patients fitted with a CRT device achieve synchronicity. Some patients are just CRT non-responders.