Early mechanical revascularization in patients with acute myocardial infarction (AMI) complicated by cardiogenic shock is a therapeutic strategy that reduces mortality. It has been a class I recommendation in guidelines from the American College of Cardiology and the American Heart Association since 1999 for patients younger than 75 years. However, little is known about implementation of these guidelines in practice. To assess trends in early revascularization and mortality for patients with cardiogenic shock complicating AMI and to determine whether the national guidelines affect revascularization rates. Prospective, observational study of 293,633 patients with ST-elevation myocardial infarction (25,311 [8.6%] had cardiogenic shock; 7356 [29%] had cardiogenic shock at hospital presentation) enrolled in the National Registry of Myocardial Infarction (NRMI) from January 1995 to May 2004 at 775 US hospitals with revascularization capability (defined as the capability to perform cardiac catheterization, percutaneous coronary intervention [PCI], and open-heart surgery). Management patterns and in-hospital mortality rates. There was an increase in primary PCI rates from 27.4% to 54.4% (P<.001) in hospitals with revascularization capability that paralleled the change in PCI for ST-elevation myocardial infarction. There was no significant change in rates of immediate coronary artery bypass graft surgery (from 2.1% to 3.2%). Propensity-adjusted multivariable analyses demonstrated that primary PCI was associated with a decreased odds of death during hospitalization (odds ratio, 0.46; 95% confidence interval, 0.40-0.53). There were no differences in the rates of change in revascularization rates based on the date when the guidelines were released regardless of patient age. Overall in-hospital cardiogenic shock mortality decreased from 60.3% in 1995 to 47.9% in 2004 (P<.001). The use of PCI for patients with cardiogenic shock was associated with improved survival in a large group of hospitals with revascularization capability. The American College of Cardiology and American Heart Association guidelines had no detectable temporal impact on revascularization rates. These findings support the need for increased adherence to these guidelines.