Role of echocardiography in cardiac resynchronization therapy

Cardiac resynchronization therapy (CRT) is an established treatment of patients with heart failure with reduced ejection fraction associated with QRS complex prolongation. However, about 30% of patients do not respond to CRT favorably, more so patients with shorter QRS duration and QRS morphology other than typical left bundle branch block. Echocardiography plays a crucial role in management of all those patients. Echocardiographic assessment of myocardial mechanics can quantitate myocardial deformation and find myocardial segments that are latest mechanically activated in a dyssynchronously contracting left ventricle. Left ventricular (LV) lead placement in this area is associated with clinical response to CRT. On the other hand, lead placement within a scar has been associated with bad prognosis. The aim of this work was to investigate whether left ventricular lead placed close to the site of latest mechanical activation is beneficial especially in patients with shorter QRS durations or atypical QRS morphology. This has been done by analyzing data of the randomized trial STARTER, which compared echo-guided LV lead navigation to routine empirical lead placement. The STARTER trial proved clinical benefit of echo-guided LV lead placement towards the site of latest mechanical activation. In our..