High-Grade Atrioventricular Block in Acute Coronary Syndromes: Insights From the Global Registry of Acute Coronary Events
What is the incidence of, and death associated with, high-grade atrioventricular block (HAVB) in acute coronary syndrome (ACS) patients receiving contemporary management?
The incidence of HAVB was determined within the Global Registry of Acute Coronary Events (GRACE). The clinical characteristics, in-hospital therapies, and outcomes were compared between patients with and without HAVB. Factors associated with death in patients with HAVB were determined.
A total of 59,229 patients with ACS between 1999 and 2007 were identified; 2.9% of patients had HAVB at any point during the index hospitalization, 22.7% of whom died in the hospital (adjusted odds ratio [OR], 4.2; 95% confidence interval [CI], 3.6-4.9; p < 0.001). The association between HAVB and in-hospital death varied with type of ACS (OR, ST-segment elevation myocardial infarction [STEMI] = 3.0; non-STEMI = 6.4; unstable angina = 8.2, p for interaction < 0.001). HAVB present at the time of presentation to the hospital (vs. occurring in-hospital) and early (<12 hours) percutaneous coronary intervention or fibrinolysis (vs. >12 hours or no intervention) were associated with improved in-hospital survival, whereas temporary pacemaker insertion was not. Patients with HAVB surviving to discharge had similar adjusted survival at 6 months compared with those without HAVB. A reduction in the rate of, but not in-hospital mortality associated with, HAVB was noted over the study period.
The authors concluded that although the incidence of HAVB is low and decreasing, this complication continues to have a high risk of in-hospital death.
This study suggests that although the incidence of HAVB with ACS is low, in-hospital mortality with this condition remains high, and likely reflects the severity of the ACS. While long-term survival is not compromised in patients with HAVB surviving the acute hospital admission, one cannot exclude impaired quality of life in this subgroup of patients related to the detrimental effects of in-hospital complications. Aggressive supportive care with reperfusion/early revascularization, in addition to pacing and potentially other interventions aimed at attenuating infarct size and minimizing additional complications associated with ACS, could have an impact on the incidence and possibly the outcomes associated with HAVB.
Keywords: Atrioventricular Block, Myocardial Infarction, Acute Coronary Syndrome, Hospital Mortality, Angina, Unstable, Quality of Life, Fibrinolysis, Percutaneous Coronary Intervention
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