Background

Patients with heart failure undergoing cardiac resynchronization therapy with or without defibrillator function may exhibit recovery of left ventricular ejection fraction (LVEF) during follow-up. Mechanical dispersion (MD; the SD of time to peak longitudinal strain by two-dimensional speckle-tracking echocardiography) is a known predictor of life-threatening ventricular arrhythmias (VAs). Relationships among LVEF recovery, changes in MD, and incidence of VA are still not extensively investigated.

Methods

In this retrospective study, recipients of cardiac resynchronization therapy defibrillation (n = 183) or implantable cardioverter-defibrillators only (n = 87) underwent conventional and speckle-tracking echocardiography, both at baseline and after 10 to 12 months, and were followed clinically. Both a ≥10% increase in LVEF and a final LVEF > 35% defined echocardiographic response (Echo_Resp). Reduction in MD ≥10 msec defined MD response (MD_Resp). Risk for appropriate implantable cardioverter-defibrillator therapy for VAs was assessed using a multivariable Cox hazard model.

Results

The prevalence of Echo_Resp+ and MD_Resp+ was 39% and 46%, respectively. During follow-up (49.8 ± 33.5 months), 74 VA events occurred. The incidence rate (per 100 patient-years) of VAs was lowest in the Echo_Resp+/MD_Resp+ group (1.66%; 95% CI, 0.69%-3.99%), highest in the Echo_Resp−/MD_Resp− group (12.8%; 95% CI, 9.53%-17.2%; P < .0001), and intermediate in the Echo_Resp−/MD_Resp+ (5.5%; 95% CI, 3.3%-9.4%) or Echo_Resp+/MD_Resp− (5.3%; 95% CI, 3.0%-9.4%) group. Multivariable analysis showed that higher MD at follow-up (>71.4 msec) was associated with VAs independent of whether final LVEF was below or above the guideline-reported cutoff of 35% (P < .05).

Conclusions

Among ICD recipients, improvements in both left ventricular function and MD are associated with reduced risk for VAs. In patients whose follow-up LVEFs improved to >35%, risk for VAs, although substantially decreased, remained elevated in the presence of still elevated MD.

中文翻译：

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左心室射血分数恢复的心脏再同步治疗除颤和植入式心脏复律除颤器受者的室性心律失常负担：斑点追踪超声心动图的附加作用

背景

接受心脏再同步化治疗的心力衰竭患者有或没有除颤器功能可能会在随访期间表现出左心室射血分数 (LVEF) 的恢复。机械离散度（MD；二维斑点追踪超声心动图纵向应变峰值时间的 SD）是威胁生命的室性心律失常 (VAs) 的已知预测因子。LVEF 恢复、MD 变化和 VA 发病率之间的关系仍未得到广泛研究。

方法

在这项回顾性研究中，心脏再同步化治疗除颤（n  = 183）或仅植入式心脏复律除颤器（n  = 87）的接受者在基线和 10 至 12 个月后接受了常规和斑点追踪超声心动图，并进行了临床随访。LVEF 增加≥10% 和最终 LVEF > 35% 都定义为超声心动图反应 (Echo _Resp )。MD 减少≥10 毫秒定义的 MD 响应 (MD _Resp )。使用多变量 Cox 风险模型评估对 VAs 进行适当的植入式心脏复律除颤器治疗的风险。

结果

Echo _Resp + 和 MD _Resp + 的患病率分别为 39% 和 46%。在随访期间（49.8 ± 33.5 个月），发生了 74 起 VA 事件。VAs 的发生率（每 100 患者年）在 Echo _Resp +/MD _Resp + 组中最低（1.66%；95% CI，0.69%-3.99%），在 Echo _Resp -/MD _Resp - 组中最高(12.8%; 95% CI, 9.53%-17.2%; P  < .0001)，在 Echo _Resp -/MD _Resp + (5.5%; 95% CI, 3.3%-9.4%) 或 Echo _Resp +/中间_董事总经理− （5.3%；95% CI，3.0%-9.4%）组。多变量分析表明，随访时更高的 MD (>71.4 毫秒) 与 VA 相关，与最终 LVEF 是否低于或高于指南报告的 35% 截止值无关 ( P  < .05)。

结论

在 ICD 接受者中，左心室功能和 MD 的改善与 VA 风险降低有关。在随访 LVEF 改善至 >35% 的患者中，VA 的风险虽然显着降低，但在 MD 仍然升高的情况下仍然升高。