Background: The high-grade atrioventricular block (HAVB) occurrence in acute coronary syndrome (ACS) is a potentially life-threatening complication, that demands a rapid and efficient response regarding reperfusion time and rhythm stabilization. This study aimed to analyse the rate, clinical features, therapeutic approach, complications, in-hospital mortality and follow-up of HAVB in the setting of ACS.

Methods: Multicenter retrospective study based on the Acute Coronary Syndrome Portuguese National Registry, including 32157 patients admitted for ACS between 1/10/2010–3/05/2020, classified according to the presence or absence of HAVB during the hospitalization for ACS. Comparison between the two groups was performed. Logistic regression was accomplished to assess predictors of HAVB in ACS patients.

Results: Patients with HAVB were older, and had higher rates of females, history of stroke and neoplasia. HAVB patients presented more frequently ST-segment elevation myocardial infarction, syncope as a major symptom, higher Killip-Kimball class and multivessel disease. Furthermore, HAVB patients had more major adverse cardiac events during the hospitalization for ACS, namely heart failure complication, cardiogenic shock complication, new-onset of atrial fibrillation, ACS mechanical complication, sustained ventricular tachycardia, cardiac arrest, stroke complication and in-hospital death. Logistic regression revealed that female gender, age ≥ 75 years old, heart rate < 60 and Killip-Kimball class > I were predictors of HAVB in ACS patients. Also, HAVB patients presented higher rates of all-causes of death at 1-year follow-up (p = 0.011).

Conclusions: Using real-life data, patients with HAVB in the setting of ACS had a worse prognosis during hospitalization and in the short-term follow-up period.

背景：急性冠状动脉综合征 (ACS) 中发生的高级别房室传导阻滞 (HAVB) 是一种可能危及生命的并发症，需要对再灌注时间和节律稳定做出快速有效的反应。本研究旨在分析 ACS 中 HAVB 的发生率、临床特征、治疗方法、并发症、院内死亡率和随访情况。

方法：基于急性冠状动脉综合征葡萄牙国家登记处的多中心回顾性研究，包括 2010 年 1 月 10 日至 2020 年 3 月 5 日期间因 ACS 入院的 32157 名患者，根据 ACS 住院期间是否存在 HAVB 进行分类。进行了两组之间的比较。完成逻辑回归以评估 ACS 患者 HAVB 的预测因子。

结果：HAVB 患者年龄较大，女性、中风和肿瘤病史的发生率较高。HAVB 患者更常出现 ST 段抬高型心肌梗死、晕厥为主要症状、Killip-Kimball 级别较高和多支血管病变。此外，HAVB患者在ACS住院期间发生的主要心脏不良事件较多，即心力衰竭并发症、心源性休克并发症、新发房颤、ACS机械并发症、持续性室性心动过速、心脏骤停、卒中并发症和院内死亡. Logistic 回归分析显示，女性、年龄≥ 75 岁、心率<60 和 Killip-Kimball 等级 > I 是 ACS 患者 HAVB 的预测因素。此外，HAVB 患者在 1 年随访时的全因死亡率较高（p = 0.011）。

结论：使用真实数据，在 ACS 情况下的 HAVB 患者在住院期间和短期随访期间的预后较差。