The first clinical manifestation of coronary artery disease (CAD) varies widely from unheralded myocardial infarction (MI) to mild, incidentally detected disease. The primary objective of this study was to quantify the association between different initial CAD diagnostic classifications and future heart failure. This retrospective study incorporated the electronic health record of a single integrated health care system. Newly diagnosed CAD was classified into a mutually exclusive hierarchy as MI, CAD with coronary artery bypass graft (CABG), CAD with percutaneous coronary intervention, CAD only, unstable angina, and stable angina. An acute CAD presentation was defined when the diagnosis was associated with a hospital admission. New heart failure was identified after the CAD diagnosis. Among 28 693 newly diagnosed CAD patients, initial presentation was acute in 47% and manifested as MI in 26%. Within 30 days of CAD diagnosis, MI hazard ratio (HR) = 5.1; 95% confidence interval: 4.1-6.5 and unstable angina (3.2; 2.4-4.4) classifications were associated with the highest heart failure risk (compared to stable angina), as was acute presentation (2.9; 2.7-3.2). Among stable, heart failure-free CAD patients followed on average 7.4 years, initial MI (adjusted HR = 1.6; 1.4-1.7) and CAD with CABG (1.5; 1.2-1.8) were associated with higher long-term heart failure risk, but an initial acute presentation was not (1.0; 0.9-1.0). Nearly 50% of initial CAD diagnoses are associated with hospitalization, and these patients are at high risk of early heart failure. Among stable CAD patients, MI remained the diagnostic classification associated with the highest long-term heart failure risk, however, having an initial acute CAD presentation was not associated with long-term heart failure.