Location of acute myocardial infarction and associated arrhythmias and outcome.

BACKGROUND

Cardiac arrhythmias and conduction abnormalities complicating acute myocardial infarction (AMI) have been associated with adverse prognosis in numerous reports. Small studies have frequently associated different arrhythmias with various distributions of myocardial infarctions. We analyzed a nationally representative hospital discharge database to evaluate the relationship between the location of AMI and the associated arrhythmias and conduction abnormalities and their impact on in-hospital mortality.

METHODS

We searched the National Hospital Discharge Survey database for patients with a diagnosis of AMI and collected data on the associated arrhythmias and conduction abnormalities. In-hospital death was used as end point for analysis.

RESULTS

A total of 21,807 patients, representing 2,632,217 hospital discharges in the United States, with a primary diagnosis of AMI from 1996 to 2003 were included in this analysis. Patients with inferior or posterior AMI were more likely to develop complete heart block compared to those with anterior or lateral AMI (3.7% vs 1.0%, hazard ratio [HR] = 3.9, p <or= 0.001), but less likely to die prior to hospital discharge (7.7% vs 11.3%, HR = 0.65, p <or= 0.001).

CONCLUSIONS

Patients with an inferior or posterior AMI are more likely to develop conduction system abnormalities when compared to patients with an anterior or lateral AMI. On the other hand, anterior or lateral MI is a significant predictor of in-hospital death.