BACKGROUND: Although dyspnea is a common symptom, there has been only limited investigation of its prognostic significance among patients referred for cardiac evaluation. METHODS: We studied 17,991 patients undergoing myocardial-perfusion single-photon-emission computed tomography during stress and at rest. Patients were divided into five categories on the basis of symptoms at presentation(none, nonanginal chest pain, atypical angina, typical angina, and dyspnea). Multivariable analysis was used to assess the incremental prognostic value of symptom categories in predicting the risk of death from cardiac causes and from any cause. In addition, the prognosis associated with various symptoms at presentation was compared in subgroups selected on the basis of propensity analysis.RESULTS: After a mean(±SD)follow-up of 2.7±1.7 years, the rate of death from cardiac causes and from any cause was significantly higher among patients with dyspnea(both those previously known to have coronary artery disease and those with no known history of coronary artery disease)than among patients with other or no symptoms at presentation. Among patients with no known history of coronary artery disease, those with dyspnea had four times the risk of sudden death from cardiac causes of asymptomatic patients and more than twice the risk of patients with typical angina. Dyspnea was associated with a significant increase in the risk of death among each clinically relevant subgroup and remained an independent predictor of the risk of death from cardiac causes(P< 0.001)and from any cause(P< 0.001)after adjustment for other significant factors by multivariable and propensity analysis. CONCLUSIONS: In a large series of patients, self-reported dyspnea identified a subgroup of otherwise asymptomatic patients at increased risk for death from cardiac causes and from any cause. Our results suggest that an assessment of dyspnea should be incorporated into the clinical evaluation of patients referred for cardiac stress testing. BACKGROUND: Although dyspnea is a common symptom, there has been only only limited investigation of its prognostic significance among patients referred for cardiac evaluation. METHODS: We studied 17,991 patients undergoing myocardial perfusion single-photon-emission computed tomography during stress and at rest. Patients were divided into five categories on the basis of symptoms at presentation (none, nonanginal chest pain, atypical angina, typical angina, and dyspnea). Multivariable analysis was used to assess the incremental prognostic value of symptom categories in predicting the risk of death from cardiac causes and from any cause. In addition, the prognosis associated with various symptoms at presentation was compared in subgroups selected on the basis of propensity analysis .RESULTS: After a mean (± SD) follow-up of 2.7 ± 1.7 years, the rate of death from cardiac causes and from any cause was significantly higher among patients with dyspnea (both those previously known to have coronary arte ry disease and those with no known history of coronary artery disease) than among patients with other or no symptoms at presentation. Among patients with no known history of coronary artery disease, those with dyspnea had four times the risk of sudden death from cardiac causes of asymptomatic patients and more than twice the risk of patients with typical angina. Dyspnea was associated with a significant increase in the risk of death among each clinically relevant subgroup and remained an independent predictor of the risk of death from cardiac causes (P <0.001) and from any cause (P <0.001) after adjustment for other significant factors by multivariable and propensity analysis. CONCLUSIONS: In a large series of patients, self-reported dyspnea identified a subgroup of otherwise asymptomatic patients at increased risk for death from cardiac causes and from any cause. Our results suggest that an assessment of dyspnea should be incorporated into the clinical evaluation of patients referred to c ardiac stress testing.