Cardiac resynchronization therapy (CRT) is an accepted treatment for patients with heart failure (HF), impaired left ventricular (LV) function, and a wide QRS complex. However, more than 30% of eligible patients fail to benefit from CRT. It is clearly necessary to define the characteristics of the best candidates for this therapy. To this end, surface ECG and echocardiography have been tested. Unfortunately, however, neither of these examinations has proved sufficiently able to identify the best patients. A tailored approach based on the evaluation of both electrical and mechanical delay to guide LV lead placement seems to be the most reasonable strategy in order to increase the efficacy of CRT therapy. The good preliminary data that have been published suggest that using intracardiac echocardiography to define the mechanical delay could be an interesting option. Moreover, at present it is the only option available that can enable intraprocedural evaluation of the mechanical activation sequence. Naturally, further randomized studies with larger populations should be performed in order to ascertain the real benefit of this approach and to evaluate whether it will outweigh the additional cost of this technology.
Credits: Antonio Rossillo; Angelo B. Ramondo