Complete Heart Block Complicating ST-Segment Elevation Myocardial Infarction: Temporal Trends and Association With In-Hospital Outcomes.

Objectives: The purpose of this study was to determine the association of complete heart block (CHB) with outcomes and to examine temporal trends in the incidence and outcomes of CHB complicating ST-segment elevation myocardial infarction (STEMI).

Background: There are limited data available on the incidence and outcomes of CHB in STEMI patients who undergo contemporary management.

Methods: We used the 2003 to 2012 National Inpatient Sample databases to identify all patients age ≥18 years hospitalized with STEMI. Patients with a concomitant diagnosis of CHB were then identified. Multivariable logistic regression was used to analyze the association of CHB with outcomes and to examine the temporal trends in incidence and outcomes of CHB complicating STEMI.

Results: Of 2,273,853 patients with STEMI, 49,882 (2.2%) had CHB. The incidence of CHB increased from 2.1% in 2003 to 2.3% in 2012 (adjusted odds ratio [OR] per year: 1.02; 95% confidence interval [CI]: 1.02 to 1.03). STEMI patients with CHB had higher in-hospital mortality than those without CHB (20.4% vs. 8.7%; adjusted OR: 2.47; 95% CI: 2.41 to 2.53). The higher mortality associated with CHB was independent of the location of STEMI; however, the magnitude of this association was greatest in patients with anterior STEMI. In patients with CHB complicating STEMI, although permanent pacemaker implantation rates declined (adjusted OR per year: 0.96; 95% CI: 0.95 to 0.97), in-hospital mortality remained unchanged during the study period (adjusted OR per year: 1.00; 95% CI: 0.99 to 1.01).

Conclusions: The incidence of CHB complicating STEMI has increased slightly over the last decade, although the absolute incidence remains quite low. CHB remains associated with higher in-hospital mortality in STEMI patients even in the current era of prompt reperfusion therapy. In patients with CHB complicating STEMI, there was no change in risk-adjusted in-hospital mortality during the study period.