Purpose

Response to cardiac resynchronization therapy (CRT) in patients with heart failure with reduced ejection fraction (HFrEF) depends on the degree of correction of interventricular (VV) electromechanical dyssynchrony between the left and right ventricles (LV, RV). Wide (> 130 ms [ms]) QRS interval is used as a qualifying ECG parameter for CRT device implantation. In this study, we aimed to evaluate myocardial strain (S) and myocardial strain patterns (SP) and strain rate (SR) by speckle tracking echocardiography (STE) and mechanical characteristics at different VV intervals in acute settings and long-term outcome from “sequential LV-RV” pacing programming in patients with narrow (< 130 ms) and wide (> 130 ms) QRS complexes as a basis for extending CRT in select patients with narrow QRS.

Methods

From a previously established cohort of patients who had undergone CRT device implantation, we identified patients with narrow (< 130 ms) and wide (> 130 ms) QRS complexes, groups A and B respectively. In all patients, we assessed myocardial SP and SR by STE, and mechanical characteristics at VV intervals: “LV Off,” “VV0,” “VV60,” and “RV Off” to provide “RV-only,” “simultaneous BiV,” “sequential LV-RV,” and “LV-only” pacing in the acute settings, and subsequently long-term clinical outcomes with CRT devices programmed to VV60. We compared acute STE characteristics and long-term clinical outcomes between the groups.

Results

The study cohort comprised 271 patients (age 69.2 ± 10.3 years [mean ± SD], male—60%). Group A (n = 69) and group B (n = 202) were well matched for the clinical variables, including distribution of patients with ischemic versus non-ischemic cardiomyopathies. QRS width and left ventricular ejection fraction (LVEF) in groups A and B were 120.1 ± 12.3 ms and 152.1 ± 12.9 ms (p < 0.05), and 22.3 ± 9.4%, and 23.3 ± 10.2% (p = not significant [NS]). With VV0, VV60, and LV-only timings, corresponding LVEF rates in the acute settings were 31.45 ± 10.9%, 40.08 ± 8.3%, and 44.32 ± 7.98% (p < 0.01) in group A, and 38.94 ± 8.5%, 46.91 ± 7.33%, and 49.9 ± 8.94% (p < 0.01) in group B, and accounted for similar incremental percentage increase in LVEF compared to baseline in group A (43.2 ± 51.7%, 80.9 ± 61.4%, and 93.4 ± 65.6% respectively) and group B (67.3 ± 82.0%, 100.6 ± 94.3%, and 112.9 ± 95.7% respectively) (p = NS). Abnormal SP and SR were consistently observed with RV pacing that improved with VV60 and LV-only pacing in both groups. Strain scores at different VV timings were similar between the groups (p = NS). At 1-year follow-up, LVEF improved from 22.4 ± 8.0% to 39.8 ± 11.5% (p ≤ 0.001) for the total cohort with similar increments observed in both groups (p = NS). There were fewer NYHA III–IV class patients at 1 year in both groups.

Conclusions

Comparable myocardial SP and SR characteristics and LVEF improvement with VV60 and LV-only pacing in the acute setting and long-term outcome of CRT by “sequential LV-RV” pacing seen in patients with both narrow and wide QRS duration suggest that CRT device implantation may be justified in select patients with HFrEF and narrow QRS duration (< 130 ms) who have demonstrable dyssynchrony and abnormal myocardial SP and SR characteristics.

中文翻译：

---

心力衰竭和窄 QRS 波群 (≤ 130 ms) 患者的心脏再同步化治疗：斑点追踪超声心动图和不同心室 (VV) 起搏间隔的作用

目的

射血分数降低的心力衰竭 (HFrEF) 患者对心脏再同步化治疗 (CRT) 的反应取决于左右心室 (LV, RV) 之间的心室间 (VV) 机电不同步的纠正程度。宽 (> 130 ms [ms]) QRS 间期用作 CRT 设备植入的合格 ECG 参数。在这项研究中，我们旨在通过斑点追踪超声心动图 (STE) 评估心肌应变 (S) 和心肌应变模式 (SP) 以及应变率 (SR)，以及在急性环境中不同 VV 间隔的机械特性和长期结果。对窄 (< 130 ms) 和宽 (> 130 ms) QRS 复合波患者的序贯 LV-RV” 起搏程序作为在选定的窄 QRS 患者中延长 CRT 的基础。

方法

从先前建立的接受 CRT 装置植入的患者队列中，我们分别确定了 A 组和 B 组具有窄 (< 130 ms) 和宽 (> 130 ms) QRS 复合波的患者。在所有患者中，我们通过 STE 评估了心肌 SP 和 SR，以及 VV 间期的机械特性：“LV Off”、“VV0”、“VV60”和“RV Off”以提供“仅 RV”、“同时 BiV、 ” “顺序 LV-RV”和“仅 LV”起搏在急性环境中，以及随后使用编程为 VV60 的 CRT 设备的长期临床结果。我们比较了各组之间的急性 STE 特征和长期临床结果。

结果

研究队列包括 271 名患者（年龄 69.2 ± 10.3 岁 [平均值 ± SD]，男性 - 60%）。A 组 (n = 69) 和 B 组 (n = 202) 的临床变量非常匹配，包括缺血性与非缺血性心肌病患者的分布。A 组和 B 组的 QRS 宽度和左心室射血分数 (LVEF) 分别为 120.1 ± 12.3 ms 和 152.1 ± 12.9 ms (p < 0.05)、22.3 ± 9.4% 和 23.3 ± 10.2% (p = 不显着 [NS] ）。对于 VV0、VV60 和仅 LV 时间，急性环境中相应的 LVEF 率在 A 组分别为 31.45 ± 10.9%、40.08 ± 8.3% 和 44.32 ± 7.98% (p < 0.01)，以及 38.94 ± 8.5%、46.91 B 组分别为 ± 7.33% 和 49.9 ± 8.94% (p < 0.01)，与 A 组的基线相比，LVEF 的增量百分比增加相似（43.2 ± 51.7%、80.9 ± 61.4% 和 93.4 ± 65。分别为 6%）和 B 组（分别为 67.3 ± 82.0%、100.6 ± 94.3% 和 112.9 ± 95.7%）（p = NS）。RV 起搏持续观察到 SP 和 SR 异常，两组均使用 VV60 和仅 LV 起搏改善。不同 VV 时间的应变分数在各组之间相似 (p = NS)。在 1 年的随访中，总队列的 LVEF 从 22.4 ± 8.0% 提高到 39.8 ± 11.5% (p ≤ 0.001)，两组观察到的增量相似 (p = NS)。两组在 1 年时的 NYHA III-IV 级患者较少。总队列为 8 ± 11.5% (p ≤ 0.001)，两组观察到的增量相似 (p = NS)。两组在 1 年时的 NYHA III-IV 级患者较少。总队列为 8 ± 11.5% (p ≤ 0.001)，两组观察到的增量相似 (p = NS)。两组在 1 年时的 NYHA III-IV 级患者较少。

结论

可比较的心肌 SP 和 SR 特征和 LVEF 改善与 VV60 和仅 LV 起搏在急性设置和 CRT 的长期结果通过在窄和宽 QRS 持续时间的患者中看到的“顺序 LV-RV”起搏表明 CRT 装置植入对于具有明显不同步和异常心肌 SP 和 SR 特征的 HFrEF 和窄 QRS 持续时间（< 130 ms）的特定患者可能是合理的。