Department of Internal Medicine, Cardiovascular Division, University of Miami Miller School of Medicine, Miami, FL, USA.
Am J Cardiol. 2013 Sep 1;112(5):671-7. doi: 10.1016/j.amjcard.2013.04.040. Epub 2013 May 29.
The relation of bundle branch block (BBB) with adverse outcome is controversial. We hypothesized that increased QRS duration is an independent predictor of cardiovascular (CV) mortality in a cross-sectional US population. This is a retrospective cohort study on prospectively collected data to assess the relationship between QRS duration on routine ECG and CV mortality. Participants included 8,527 patients with ECG data available from the National Health and Nutrition Examination Survey data set, representing 74,062,796 individuals in the United States. Mean age was 60.5 ± 13.6 years. Most subjects were white (87%) and women (53%). During the follow-up period of 106,244.6 person-years, 1,433 CV deaths occurred. Multivariate analysis revealed that the highest quartile of QRS duration was associated with higher CV mortality than lowest quartile (hazard ratio [HR] 1.3, 95% confidence interval [CI] 1.01 to 1.7, p = 0.04) after adjustment for established risk factors. Both left BBB (HR 2.4, 95% CI 1.3 to 4.7, p = 0.009) and right BBB (HR 1.90, 95% CI 1.2 to 3.0, p = 0.008) were significantly associated with increased CV mortality. The addition of the QRS duration in 10-millisecond increments to the Framingham Risk Score model resulted in 4.4% overall net reclassification improvement (95% CI 0.02 to 0.04; p = 0.00006). In conclusion, increased QRS duration was found to be an independent predictor of CV mortality in this cross-sectional US population. A model including QRS duration in addition to traditional risk factors was associated with improved CV risk prediction.
束支传导阻滞（BBB）与不良预后的关系存在争议。我们假设，QRS 波时限延长是美国横断面人群心血管（CV）死亡率的独立预测因素。这是一项回顾性队列研究，对前瞻性收集的数据进行评估，以评估常规心电图上 QRS 时限与 CV 死亡率之间的关系。参与者包括来自国家健康和营养检查调查数据集的心电图数据可用的 8527 名患者，代表美国 74062796 个人。平均年龄为 60.5 ± 13.6 岁。大多数患者为白人（87%）和女性（53%）。在 106244.6 人年的随访期间，发生了 1433 例 CV 死亡。多变量分析显示，与最低四分位数相比，QRS 时限的最高四分位数与更高的 CV 死亡率相关（危险比 [HR] 1.3，95%置信区间 [CI] 1.01 至 1.7，p = 0.04），调整后为既定危险因素。左束支传导阻滞（HR 2.4，95%CI 1.3 至 4.7，p = 0.009）和右束支传导阻滞（HR 1.90，95%CI 1.2 至 3.0，p = 0.008）与 CV 死亡率增加显著相关。将 QRS 时限每增加 10 毫秒加入 Framingham 风险评分模型，导致总体净分类改善 4.4%（95%CI 0.02 至 0.04；p = 0.00006）。总之，在这项美国横断面人群研究中，QRS 时限延长被发现是 CV 死亡率的独立预测因素。包括 QRS 时限和传统危险因素的模型与改善 CV 风险预测相关。
