IS THERE A COMPARABLE BENEFIT OF CARDIAC RESYNCHRONIZATION THERAPY IN PATIENTS RECEIVING AN UPGRADE OF EXISTING DEVICE VS NEW IMPLANT ?

Introduction: Cardiac resynchronization therapy ( CRT ) benefits patients ( pts ) with advanced heart  failure. However, outcomes of CRT upgrade from an existing pacemaker  or defibrillator  in comparison to a de novo device are limited.
Methods:  The cohort consists of 521 consecutive pts ( mean age 66 ± 12 years, male 76% ) who received CRT-P ( 8% ) or CRT-D  ( 92% ) from 1/2004 to 12/2006. Of these, 376 ( 72% ) pts received a de novo device while the remaining 145 ( 28% ) had CRT upgrade from an existing device. Survival data were obtained from the location database. NYHA class and echocardiography were assessed before and after CRT.
Results: Baseline demographics were similar in the upgrade and de novo groups, although chronic AF was more common in the upgrade group ( 43% vs 25%, p<0.001 ). There was no significant  difference in mortality rates over a median follow-up period of 2.6 year ( p=0.67 ). At four years, the respective death rates for the  de novo and upgrade groups were 37% and 33%. Comparisons in NYHA class and echocardiographic parameters between the 2 groups are shown in table (*p<0.05 compared to pre-CRT ). NYHA class and left ventricular ( LV ) function similarly improved in both groups. There was no significant difference in changes in these parameters after CRT between groups.
Conclusions:  One quarter of pts meeting the indication for CRT receive an upgrade device from an existing pacemaker or defibrillator. In comparison to those having a de novo device, this patient population achieves a comparable outcome in survival and reversal of LV remodeling from CRT.