Cardiac resynchronization therapy and the emerging role of echocardiography (part 1): indications and results from current studies.

Cardiac resynchronization therapy (CRT) has been established as an adjunctive treatment for patients with left ventricular systolic dysfunction and medically refractory heart failure with a wide QRS interval. Echocardiography can be used to determine the response in left ventricular structure and function after device implantation and emerging evidence as a method for selection of patients who may derive clinical benefit from CRT. This review discusses the applications of CRT, including results of clinical trials and the current experience using echocardiography. Part 2 will address the practical aspects of obtaining echocardiographic data in patients who are potential candidates for CRT and optimization of pacemaker settings after device implantation.