Mazza Andrea, Bendini Maria Grazia, De Cristofaro Raffaele, Lovecchio Mariolina, Valsecchi Sergio, Leggio Massimo, Boriani Giuseppe
Cardiology Department, Santa Maria della Stella Hospital, Orvieto, Italy.
CRM department, Boston Scientific, Milan, Italy.
Clin Cardiol. 2017 Jun;40(6):377-382. doi: 10.1002/clc.22673. Epub 2017 Mar 10.
Previous studies have shown that the presence of left bundle branch block (LBBB) is associated with an increased risk of cardiac mortality and heart failure (HF). Recently, new criteria to define strict LBBB have been proposed: QRS duration ≥140 ms for men and ≥130 ms for women, along with mid-QRS notching or slurring in ≥2 contiguous leads.
We assessed the prevalence and prognostic significance of LBBB according to classical (QRS duration ≥120ms) and strict criteria in permanent pacemaker patients.
We retrospectively enrolled 723 consecutive patients who had undergone single- or dual-chamber pacemaker implantation at the study center from July 2002 to December 2014. Patients with a left ventricular ejection fraction ≤35% or a prior diagnosis of HF were excluded.
LBBB was reported in 54 (7%) patients, and strict-LBBB in 15 (2%) patients. During a median follow-up of 48 months (range, 18-92 months), 147 (20%) patients reached the combined endpoint of death or HF hospitalization. Patients with LBBB and those with strict-LBBB displayed significantly higher rates of death or HF hospitalization (log-rank test, all P < 0.0001). In particular, strict-LBBB was associated with the worst outcome. The presence of LBBB according to classical definition criteria (hazard ratio [HR] = 1.98, confidence interval [CI]: 1.23-3.19, P = 0.005) and to strict criteria (HR = 2.20; CI: 1.04-4.65; P = 0.039) were both confirmed as independent predictors of death or HF hospitalization after adjustment for relevant clinical covariates.
Among patients who had undergone standard pacemaker implantation, the prevalence of LBBB was 7% according to classical definition criteria and 2% according to strict criteria. The presence of LBBB, and particularly of strict-LBBB, at the baseline predicted a poor outcome in terms of death or HF hospitalization.
既往研究表明，左束支传导阻滞（LBBB）的存在与心脏死亡及心力衰竭（HF）风险增加相关。最近，有人提出了定义严格LBBB的新标准：男性QRS时限≥140毫秒，女性≥130毫秒，同时在≥2个相邻导联中存在QRS波峰切迹或顿挫。
我们根据经典标准（QRS时限≥120毫秒）和严格标准评估了永久性起搏器患者中LBBB的患病率及预后意义。
我们回顾性纳入了2002年7月至2014年12月在研究中心接受单腔或双腔起搏器植入的723例连续患者。排除左心室射血分数≤35%或既往诊断为HF的患者。
54例（7%）患者报告有LBBB，15例（2%）患者有严格LBBB。在中位随访48个月（范围18 - 92个月）期间，147例（20%）患者达到死亡或HF住院的联合终点。LBBB患者和严格LBBB患者的死亡或HF住院率显著更高（对数秩检验，所有P < 0.0001）。特别是，严格LBBB与最差结局相关。根据经典定义标准存在LBBB（风险比[HR] = 1.98，置信区间[CI]：1.23 - 3.19，P = 0.005）以及根据严格标准存在LBBB（HR = 2.20；CI：1.04 - 4.65；P = 0.039）在对相关临床协变量进行调整后均被确认为死亡或HF住院的独立预测因素。
在接受标准起搏器植入的患者中，根据经典定义标准LBBB的患病率为7%，根据严格标准为2%。基线时存在LBBB，尤其是严格LBBB，预示着在死亡或HF住院方面预后不良。
