Background

QRS duration and morphology including left bundle branch block (LBBB) are the most widely used electrocardiogram (ECG) markers for assessing ventricular dyssynchrony and predicting heart failure (HF). However, the vectorcardiographic QRS area may more accurately identify delayed left ventricular activation and HF development.

Objective

We investigated the association between QRS area and incident HF risk in patients with LBBB.

Methods

By crosslinking data from Danish nationwide registries, we identified patients with a first-time digital LBBB ECG between 2001 and 2015. The vectorcardiographic QRS area was derived from a 12‑lead ECG using the Kors transformation method and grouped into quartiles. The endpoint was a composite of HF diagnosis, filled prescriptions for loop diuretics, or death from HF. Cause-specific multivariable Cox regression was used to compute hazard ratios(HR) with 95% confidence intervals(CI).

Results

We included 3316 patients with LBBB free from prior HF-related events (median age, 72 years; male, 40%). QRS area quartiles comprised Q1, 36–98 μVs; Q2, 99–119 μVs; Q3, 120–145 μVs; and Q4, 146–295 μVs. During a 5-year follow-up, 31% of patients reached the composite endpoint, with a rate of 39% in the highest quartile Q4. A QRS area in quartile Q4 was associated with increased hazard of the composite endpoint (HR:1.48, 95%CI:1.22–1.80) compared with Q1.

Conclusions

Among primary care patients with newly discovered LBBB, a large vectorcardiographic QRS area (146–295 μVs) was associated with an increased risk of incident HF diagnosis, filling prescriptions for loop diuretics, or dying from HF within 5-years.

中文翻译：

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矢量心电图 QRS 波区与左束支传导阻滞患者心力衰竭诊断和死亡率的关系：一项基于登记册的队列研究

背景

QRS 持续时间和形态包括左束支传导阻滞 (LBBB) 是最广泛使用的心电图 (ECG) 标志物，用于评估心室不同步和预测心力衰竭 (HF)。然而，矢量心电图 QRS 区可能更准确地识别延迟的左心室激动和 HF 发展。

客观的

我们调查了 LBBB 患者 QRS 区与突发 HF 风险之间的关联。

方法

通过交联丹麦全国登记处的数据，我们确定了 2001 年至 2015 年期间首次进行数字 LBBB 心电图的患者。矢量心电图 QRS 区使用 Kors 转换方法从 12 导联心电图获得，并分组为四分位数。终点是心衰诊断、袢利尿剂处方或心衰死亡的综合结果。特定原因的多变量 Cox 回归用于计算具有 95% 置信区间 (CI) 的风险比 (HR)。

结果

我们纳入了 3316 名没有既往 HF 相关事件的 LBBB 患者（中位年龄，72 岁；男性，40%）。QRS 区四分位数包括 Q1，36–98 μVs；Q2，99–119 μVs；Q3，120–145 μVs；和 Q4，146–295 μVs。在 5 年的随访中，31% 的患者达到了复合终点，最高四分位数 Q4 的比例为 39%。与 Q1 相比，四分位数 Q4 中的 QRS 区与复合终点的风险增加有关（HR：1.48，95%CI：1.22–1.80）。

结论

在新发现 LBBB 的初级保健患者中，大的矢量心电图 QRS 区（146-295 μV）与 HF 诊断、填写袢利尿剂处方或 5 年内死于 HF 的风险增加有关。