Cardiac resynchronization therapy: technical issues

Technical aspects of cardiac resynchronization therapy include precise delineation of the target population, the type of device required, the implantation procedure and the evaluation of delivery of therapy. Selection of candidates was initially based on ECG measurement of a wide QRS, but it is evolving toward mechanical identification of cardiac dyssynchrony. Implantation via the coronary sinus route is the preferred approach, with angiography performed either before or at the start of the procedure. Various tools have been developed, including guides, stylets and preshaped leads, which can improve the implant success rate to nearly 90%. Thoracic surgery can be performed if the endovenous technique fails. Unfortunately, the choice of device currently relates more to local reimbursement and financial support than to ideal. medical selection. Follow-up of patients and their devices is based on clinical examination, synchronizer interrogation, and ECG and echocardiographic measurements. Criteria for correct delivery of therapy remain to be determined. (C) 2003 The European Society of Cardiology. Published by Elsevier Science Ltd. All rights reserved.