Optimizing atrioventricular and interventricular intervals following cardiac resynchronization therapy

The number of cardiac resynchronization therapy (CRT) device implantations has been increasing exponentially, with the implant rate doubling over the past few years. While the majority of CRT recipients enjoy symptomatic relief, approximately 30% of individuals reap no benefit and only a minority are rendered completely symptom free. In response, many clinicians engage in the theoretically advantageous process of postimplantation optimization of atrial and ventricular stimulation by altering atrioventricular and interventricular pacing intervals. However, the rationale for routine CRT optimization and the methods of doing so have been the subjects of recent debate. Here, we present an overview of the background, techniques and evidence for CRT optimization.