Abstract 14042: Cmr Demonstrates Key Differences in Patients Undergoing De Novo CRT versus CRT Upgrades

Abstract

Introduction: Patients with cardiac resynchronization therapy (CRT) upgrades with right ventricular pacing (RVP) dependence may have a different prognosis after CRT and require a distinct implementation strategy. Hypothesis: Left ventricular (LV) size/function, optimal AHA segments for LV pacing, and survival post-CRT is different for patients with RV pacing undergoing CRT upgrade procedures. Methods: Cardiac magnetic resonance (CMR) with cine imaging, DENSE strain mechanical activation mapping, and scar imaging was performed prior to implants of CRT systems that were "de novo" (Group 1) or upgraded from pre-existing pacemakers or ICDs with RVP (Group 2) and without RVP (Group 3). Optimal LV pacing sites were identified based on latest activation. Patients were followed for clinical outcomes. Results: In 92 patients (23.5% female, 65.8 ± 10.7 years old), the baseline LVEDVI by CMR was significantly smaller in RVP upgrade (Group 2) patients (101.8 +/- 34.3 cc/m 2 ) compared with de novo (Group 1; 140.5 +/- 38.2 cc/m 2 ); p=0.001) and non-RVP upgrade patients (Group 3; 153.6 +/- 46.4 cc/m 2 ; p=0.001) (Figure 1). RVP upgrade patients also had the widest baseline QRS (178.2 +/- 26.6 ms v. 159.7 +/- 18.5 ms in Group 1 v. 154.5 +/- 20.1 ms in Group 3; p = 0.001) and were more likely to have latest mechanical activation in an anterior LV segment (50%) versus Group 1 (10%) and Group 3 (35%) patients (p = 0.0007). As shown in Figure 2, RVP upgrade patients had the worst survival (p = 0.007). Conclusion: Patients with RVP dependence undergoing CRT upgrades are more likely to have smaller baseline LV volumes by CMR, greater QRS durations, optimal pacing sites in anterior segments, and unfavorable survival.