Kondo Shun, Inden Yasuya, Yanagisawa Satoshi, Miyamae Kiichi, Miyazawa Hiroyuki, Goto Takayuki, Tachi Masaya, Iwawaki Tomoya, Yamauchi Ryota, Hiramatsu Kei, Shimojo Masafumi, Tsuji Yukiomi, Murohara Toyoaki
Department of Cardiology, Nagoya University Graduate School of Medicine, Nagoya, Japan.
ESC Heart Fail. 2025 Jun;12(3):2210-2224. doi: 10.1002/ehf2.15246. Epub 2025 Feb 20.
Cardiac resynchronization therapy (CRT) improves the prognosis of patients with heart failure (HF) and wide QRS complex. However, patients with non-left bundle branch block (LBBB) show a poor response to CRT. This study evaluated myocardial work estimated by pressure-strain loops on echocardiography for predicting response to CRT in patients with non-LBBB.
Of 267 patients who underwent CRT implantation, 54 patients with non-LBBB (mean age, 62 ± 12 years, 72% males, and 24% with ischemic cardiomyopathy) were retrospectively included. Two-dimensional speckle-tracking echocardiography was performed before and at 6-month follow-up in all patients. Myocardial work was estimated by pressure-strain loop analysis using speckle-tracking echocardiography and non-invasive blood pressure measurement. CRT response was defined as a ≥15% decrease in left ventricular end-systolic volume on echocardiography at the 6-month follow-up. The mean left ventricular ejection fraction (LVEF) before implantation was 27% ± 8% in total. Six months after implantation, 18 patients (33%) responded to CRT. The absolute LVEF improvement for responders and non-responders were 5.5% ± 6.9% and 1.3% ± 7.5%, respectively (P = 0.021). Baseline global work index (GWI), which is the average myocardial work based on the pressure-strain loop, was significantly higher in the responder group than in the non-responder group (590 ± 271 vs. 409 ± 216 mmHg%; P = 0.010). Multivariable analysis showed GWI to be an independent predictor of CRT response (odds ratio, 1.109; 95% confidence interval [CI], 1.013-1.213; P = 0.024). Receiver operating characteristic curve analysis determined the cut-off value of GWI for response as 456 mmHg% (AUC 0.700, 95% CI 0.553-0.840; P = 0.019). During the median 37-month follow-up, all-cause death occurred in 21 patients (39%). On multivariable analysis, GWI ≤ 456 mmHg% was independently associated with an increased risk of all-cause mortality (hazard ratio, 2.882; 95% CI, 1.157-7.176; P = 0.023).
High GWI assessed by speckle-tracking echocardiography and a non-invasively estimated LV pressure curve was independently associated with a favourable response to CRT and improved outcomes in patients with non-LBBB. The use of this non-invasive approach for quantifying myocardial variability and residual contractility can be beneficial for assessing CRT candidates and allow for more accurate patient stratification. Further, large multicentre studies are required to validate these findings.
心脏再同步治疗（CRT）可改善心力衰竭（HF）合并宽QRS波群患者的预后。然而，非左束支传导阻滞（LBBB）患者对CRT反应较差。本研究评估了超声心动图压力-应变环估算的心肌做功，以预测非LBBB患者对CRT的反应。
在267例行CRT植入的患者中，回顾性纳入54例非LBBB患者（平均年龄62±12岁，男性占72%，缺血性心肌病患者占24%）。所有患者在植入前及随访6个月时均行二维斑点追踪超声心动图检查。采用斑点追踪超声心动图和无创血压测量，通过压力-应变环分析估算心肌做功。CRT反应定义为随访6个月时超声心动图测得的左心室收缩末期容积减少≥15%。植入前左心室射血分数（LVEF）平均为27%±8%。植入后6个月，18例患者（33%）对CRT有反应。有反应者和无反应者的LVEF绝对改善分别为5.5%±6.9%和1.3%±7.5%（P=0.021）。基于压力-应变环的平均心肌做功即基线整体做功指数（GWI），有反应组显著高于无反应组（590±271 vs. 409±216 mmHg%；P=0.010）。多变量分析显示GWI是CRT反应的独立预测因子（比值比，1.109；95%置信区间[CI]，1.013-1.213；P=0.024）。受试者工作特征曲线分析确定GWI对反应的截断值为456 mmHg%（曲线下面积0.700，95% CI 0.553-0.840；P=0.019）。在中位37个月的随访期间，21例患者（39%）发生全因死亡。多变量分析显示GWI≤456 mmHg%与全因死亡风险增加独立相关（风险比，2.882；95% CI，1.157-7.176；P=0.023）。
通过斑点追踪超声心动图和无创估算的左心室压力曲线评估的高GWI，与非LBBB患者对CRT的良好反应及改善的预后独立相关。使用这种无创方法量化心肌变异性和残余收缩力，有助于评估CRT候选患者，并实现更准确的患者分层。此外，需要大型多中心研究来验证这些发现。
