2022 Volume 49 Issue 2 Pages 81-86
In the cardiac resynchronization therapy (CRT) era, it has been widely known that electrical conduction disturbance, particularly left bundle branch block (LBBB), contributes to the deterioration of cardiac function. So far, evidence of the effectiveness of CRT has been established in LBBB, but it is controversial with non-LBBB-type electrical conduction disorders such as right bundle branch block. However, dyssynchrony of left ventricular wall motion differs even in LBBB, and some patients with LBBB may not respond to CRT. Therefore, while it is important to respect the recommended level of guidelines in determining the indication for CRT, the perspective of personalized medicine is even more important. Unfortunately, the current guidelines do not include echocardiographic parameters, but echocardiography is useful in assessing cardiac dyssynchrony based on mechanical properties. Many indices have been reported to predict CRT response and to determine adaptation. Various techniques have been proposed for CRT studies, including M-mode, tissue Doppler, speckle tracking, and 3D echocardiography. CRT devices are also constantly evolving and are now equipped with a more complex sequence of cardiac pacing. Therefore, the adaptation of advanced image technique, such as 3D speckle tracking methods, may be necessary to determine the indications for CRT from the viewpoint of personalized medicine.
