Percent biventricular pacing in cardiac resynchronization therapy: Is more always better?

Abstract

c b s i t w t c h Cardiac resynchronization therapy (CRT) has been shown to improve outcomes in selected heart failure patients. However, approximately 30% of patients fail to respond favorably, with loss of consistent pacing being one reason for a poor response. In this issue of Heart Rhythm, Hayes et al report on the importance of biventricular (BiV) pacing xpressed as a percentage of total ventricular beats in a large ohort of the patients with CRT devices from a single anufacturer. The data derive from the LATITUDE remote onitoring patient management system (Boston Scientific, nc., Natick, MA, USA). Since its introduction in 2006, the ATITUDE network has enrolled more than 150,000 paients, with greater than 7 million remote transmissions ogged into the database. These data are managed by the LTITUDE clinical science program in collaboration with physician panel that assists in identifying clinical relevant ssues and patient populations for post hoc analysis. Unlike andomized clinical studies, this postmarketing analysis of evice therapy provides a unique opportunity to monitor utcomes in real world practice. A recent analysis by this roup of survival in more than 180,000 patients treated with n implantable cardioverter-defibrillator and CRT devices howed that survival rates over 5 years were very similar to hose documented in the larger randomized clinical trials. The present analysis from the ALTITUDE project sought to assess the extent of BiV pacing required for achieving maximal symptomatic and mortality benefit from CRT. A otal of 36,935 patients implanted with a CRT defibrillator rom 1,243 U.S. centers were evaluated. Data on percent iV pacing and atrial fibrillation (AF) were obtained from he LATITUDE networked remote transmissions and surival status from the Social Security Death Index. Symptom tatus was collected from a subset of patients who comleted a brief questionnaire as part of their weekly remote ransmissions. The primary findings were as follows: (1) a igher percentage of BiV pacing was associated with lower ortality and fewer heart failure symptoms; and (2) AF was