Department of Cardiovascular Medicine, Cleveland Clinic Foundation, Cleveland, Ohio.
Department of Cardiovascular Medicine, SUNY Downstate College of Medicine, Brooklyn, New York.
Am J Cardiol. 2019 Oct 1;124(7):1049-1055. doi: 10.1016/j.amjcard.2019.06.024. Epub 2019 Jul 15.
The prognosis associated with prolonged intraventricular conduction on electrocardiogram (ECG) remains uncertain. We aimed to compare clinical outcomes of narrow versus prolonged intraventricular conduction on ECG stratified by QRS morphology and cardiovascular disease (CVD) status. A post-hoc analysis was performed of the randomized-control PRECISION trial. Patients with centrally adjudicated, nonpaced baseline ECGs were included. QRS duration was classified narrow (≤100 ms) versus prolonged (>100 ms) with additional categorization into left (LBBB) or right (RBBB) bundle branch block or nonspecific intraventricular conduction delay (IVCD). IVCD was subclassified if left ventricular conduction delay (LVCD) was present (L-IVCD) or absent (O-IVCD). The primary outcome was adjudicated all-cause and cardiovascular (CV) mortality. Of 24,081 patients randomized, 22,067 (92%) were included with follow-up 34 ± 13 months. Study patients were 63 ± 9 years, 64% female, 75% Caucasian, 23% with established CVD. The prevalence of QRS prolongation was 5.6% (1,240): 760 right bundle branch block (3.4%), 313 LBBB (1.4%), and 161 IVCD (0.7%), 95 subclassified L-IVCD (0.4%). After adjustment, LBBB and L-IVCD were similarly associated with increased all-cause (LBBB: 2.3 [1.4 to 3.8], p = 0.001; L-IVCD: 4.0 [2.1 to 7.9], p <0.001) and CV (LBBB: 3.6 [2.0 to 6.5], p <0.001; L-IVCD 3.6 [1.3 to 9.7], p = 0.001) mortality. The presence of LVCD (LBBB or L-IVCD) was associated with all-cause (2.8 [1.8 to 4.2], p <0.001) and CV (3.6 [2.2 to 6.1], p <0.001) mortality exceeding the observed risks of coronary artery disease, left ventricular hypertrophy, or diabetes. The LVCD hazard persisted across QRS durations (100 to 120 vs >120 ms) and CVD status. In conclusion, LVCD, whether LBBB or L-IVCD, was strongly associated with increased mortality in patients with and at-risk for CVD.
心电图（ECG）上的室内传导延长与预后的关系尚不确定。我们旨在比较心电图 QRS 形态和心血管疾病（CVD）状态分层下，QRS 时限狭窄与延长的临床结局。对随机对照 PRECISION 试验进行了事后分析。纳入了中心裁决的、无起搏的基线心电图患者。QRS 时限分为狭窄（≤100ms）和延长（>100ms），并进一步分为左束支传导阻滞（LBBB）或右束支传导阻滞（RBBB）或非特异性室内传导延迟（IVCD）。如果存在左室传导延迟（LVCD），则将 IVCD 进一步分类为 L-IVCD，如果不存在 LVCD，则为 O-IVCD。主要结局是确定的全因和心血管（CV）死亡率。在 24081 名随机患者中，22067 名（92%）被纳入，随访 34±13 个月。研究患者的年龄为 63±9 岁，64%为女性，75%为白种人，23%有已确诊的 CVD。QRS 延长的患病率为 5.6%（1240 例）：760 例右束支传导阻滞（3.4%），313 例 LBBB（1.4%），161 例 IVCD（0.7%），95 例分类为 L-IVCD（0.4%）。调整后，LBBB 和 L-IVCD 与全因死亡率（LBBB：2.3 [1.4 至 3.8]，p=0.001；L-IVCD：4.0 [2.1 至 7.9]，p<0.001）和 CV 死亡率（LBBB：3.6 [2.0 至 6.5]，p<0.001；L-IVCD 3.6 [1.3 至 9.7]，p=0.001）均显著相关。LVCD（LBBB 或 L-IVCD）的存在与全因（2.8 [1.8 至 4.2]，p<0.001）和 CV（3.6 [2.2 至 6.1]，p<0.001）死亡率相关，超过了冠心病、左心室肥厚或糖尿病的观察风险。LVCD 风险在 QRS 时限（100 至 120 毫秒与>120 毫秒）和 CVD 状态中持续存在。总之，LVCD，无论是 LBBB 还是 L-IVCD，与 CVD 患者和 CVD 高危患者的死亡率增加密切相关。
