New Methods: Pacing Therapy to Improve Patients with Advanced Heart Failure

Abstract

Cardiac resynchronization therapy (CRT) has evolved as an effective non pharmacological method of treating patients with heart failure (HF) and left ventricular (LV) dyssynchrony for those who have not responded adequately to medical therapy. CRT requires permanent pacing of the LV wall and restores the synchronicity of the atrio-ventricular, interventricular and intraventricular contractions, resulting in improved clinical outcomes and cardiac performance of advanced HF patients with wide QRS complex. However, a significant percentage of patients treated with CRT do not show an improvement in clinical symptoms or cardiac function. The suboptimal position of the LV pacing lead, an absence of LV dyssynchrony, myocardial scar abundance or suboptimal device programming have been related to a nonresponse to CRT. Furthermore, unsuccessful primary implantation of the LV lead into the coronary venous system has been reported in up to 10 % of patients. In the last decade the indication for CRT expanded and the improvements in lead and delivery tool technologies made CRT more accessible to patients with HF. The number of CRT recipients in the last years increased enormously. Given the fact that 95% of new CRT patients received coronary sinus (CS) leads and assuming 75% patients survival and 10% CS lead failure over 5 years, a high number of CRT recipients will require CS lead revisions or alternative LV pacing methods. Furthermore, 40% of CS lead revision cases will have no usable side branches for LV lead replacement and will need alternative approaches to LV pacing.