The description of the presenting symptom is also important. Patients with chest pain are more likely to have MI or the acute coronary syndrome (7 - 8,11,14), but up to 25% of patients with these diagnoses may present with symptoms such as shortness of breath, dizziness, or weakness, so cardiac ischemia must also be considered in patients with these symptoms. Demographic factors and traditional cardiovascular risk factors (with the very notable exception of a history of MI or coronary disease (5 - 6,20 - 21)) are of little importance in predicting the cause of acute chest pain (21 - 24). Aspects of the medical history that appreciably lower the patient's likelihood of ischemia (likelihood ratios of approximately 0.2) include reproducibility of pain with palpation or positional changes, pleuritic pain, stabbing pain, or pain radiating to the lower extremities (5 - 6,20 - 21,24). However, even these negative predictors cannot reliably exclude MI (20,25). Mrs. T.'s description of painful episodes lasting only 4 to 6 minutes may also seem “atypical,” but the duration of symptoms is not a useful predictor (5,7 - 9) unless the pain has persisted for 48 hours or more without ECG changes (5 - 6). Patients who describe their pain as similar to previous episodes of cardiac ischemia are in a high-risk category (5,18), but any chest pain carries a higher risk than no pain (7 - 8,11). Although the precise reproduction of chest pain by local palpation decreases risk (5,18), normal results on physical examination do not lower the risk (5,18,20,24).