Background: Dyspnea is a common indication for referral for cardiovascular stress testing. We sought to characterize the utility of gated SPECT stress perfusion imaging in patients referred because of a chief complaint of dyspnea. In this group comorbidities included cad 22%, hyperternsion 74%, hyperlipidemia 49%, diabetes 38%, chf 20%, copd 17%. Methods: a total of 89 consecutive (66 ± 13 yrs) patients from a total referral population of 870 pts were referred for a chief complaint of dyspnea. Patients underwent dual gated SPECT myocardial imaging utilizing either an exercise protocol or an abbreviated, 4 minute adenosine infusion (140 ug/kg/min; 4 min; 1 mph walk) with simultaneous low level exercise. Coronary artery disease was determined by calculation of summed stress scores (SSS) using the conventional, previously validated 17 segment (0–4 perfusion scale) model with a SSS>4 used as a threshold for an abnormal scan. Results: Perfusion defects diagnostic for CAD were present in 22% of the patients presenting with dyspnea and were of varying degree of severity. While mean systolic function for the overall group was normal (EF=52±15%), compared to patients with a negative nuclear scan (SSS<4) those whose study was positive (SSS≥4) had a significantly lower ejection fraction (45±13%; 54±15%;p=0.02). Multiple logistic regression analysis revealed that only age (OR=1.097; CI=1.03–1.17; p=0.008) and gated stress EF (OR=0.932 ; CI=0.88–0.98;p=0.004) were associated with presence of CAD by nuclear imaging. Neither a prior history of CAD, MI, hypertension, congestive heart failure, hyperlipidemia or COPD was predictive of a positive nuclear scan. Conclusion: clinically significant perfusion defects are found in a small but significant percentage of patients referred with an isolated complaint of dyspnea. Scan Results and Risk Category Patients Normal (SSS <4) 78% Low risk (SSS 4–8) 12% Intermediate risk (SSS 9–13) 6% High risk (SSS >13) 4%