Department of Medicine, Montreal Heart Institute, Montreal, Québec, Canada.
Department of Medicine, Montreal Heart Institute, Montreal, Québec, Canada; Montreal Health Institute Coordinating Center (MHICC), Montreal, Québec, Canada.
Can J Cardiol. 2017 Oct;33(10):1274-1282. doi: 10.1016/j.cjca.2017.07.478. Epub 2017 Jul 31.
Studies comparing biventricular (BiV) cardiac resynchronization therapy (CRT) and left ventricular (LV) pacing alone have yielded conflicting results. We recently reported the results of the Greater Evaluation of Resynchronization Therapy for Heart Failure (GREATER-EARTH) trial demonstrating similar clinical benefits of BiV and LV-CRT on exercise tolerance. We report the prespecified secondary outcomes of the GREATER-EARTH trial, comparing the impact of BiV vs LV-CRT on structural and biochemical cardiac remodelling.
Patients with a LV ejection fraction (LVEF) ≤ 35% and a QRS duration ≥ 120 ms were randomized to BiV-CRT or LV-CRT for a 6-month period, followed by crossover. The primary end point was a change in LV end-systolic volume (LVESV). Secondary end points included changes in LVEF, right ventricular (RV) dimensions and function, mitral regurgitation (MR), indices of diastolic function, systolic pulmonary artery pressure (sPAP), and disease-specific biomarkers.
One hundred twenty patients (60.9 ± 8.8 years; 75.0% men; LVEF, 24.4% ± 6.3%) were enrolled. A similar reduction in LVESV was observed, from a baseline of 162.4 ± 57.2 mL to 130.4 ± 63.4 mL with BiV pacing and 130.3 ± 59.9 mL with LV pacing (P = 0.679, BiV pacing vs LV pacing). Improvements in LVEF, RV remodelling, and N-terminal pro b-type natriuretic peptide were similar between groups. BiV pacing yielded superior outcomes with respect to LV diastolic function, indexed left atrial volume, degree of MR, and sPAP (all P < 0.05), together with decreased N-terminal propeptide of type III collagen with LV-CRT.
In this randomized double-blind crossover trial, BiV and LV pacing resulted in similar improvements in the primary LV remodelling end point (LVESV). Analyses of secondary end points revealed advantages of BiV pacing over LV pacing on several other features of cardiac remodelling, providing mechanistic insights to support the main finding of the GREATER-EARTH trial.
比较双心室（BiV）心脏再同步治疗（CRT）和左心室（LV）起搏的研究结果相互矛盾。我们最近报告了心力衰竭再同步治疗更大评估（GREATER-EARTH）试验的结果，该试验表明 BiV 和 LV-CRT 对运动耐量的临床获益相似。我们报告了 GREATER-EARTH 试验的预设次要结局，比较了 BiV 与 LV-CRT 对结构和生化心脏重塑的影响。
左心室射血分数（LVEF）≤35%和 QRS 持续时间≥120 ms 的患者被随机分配接受 BiV-CRT 或 LV-CRT 治疗 6 个月，然后交叉。主要终点是 LV 收缩末期容积（LVESV）的变化。次要终点包括 LVEF、右心室（RV）大小和功能、二尖瓣反流（MR）、舒张功能指数、收缩期肺动脉压（sPAP）和疾病特异性生物标志物的变化。
共纳入 120 例患者（60.9±8.8 岁；75.0%为男性；LVEF，24.4%±6.3%）。BiV 起搏时 LVESV 从基线的 162.4±57.2 mL 减少至 130.4±63.4 mL，LV 起搏时减少至 130.3±59.9 mL（P=0.679，BiV 起搏与 LV 起搏）。两组之间 LVEF、RV 重塑和 N 末端 pro-B 型利钠肽的改善相似。BiV 起搏在 LV 舒张功能、左心房容积指数、MR 程度和 sPAP 方面的结果优于 LV 起搏（均 P<0.05），同时与 LV-CRT 相比，III 型胶原 N 末端前肽减少。
在这项随机双盲交叉试验中，BiV 和 LV 起搏均使主要 LV 重塑终点（LVESV）得到改善。对次要终点的分析显示，BiV 起搏在心脏重塑的其他几个方面优于 LV 起搏，为支持 GREATER-EARTH 试验的主要发现提供了机制见解。
