{'fraction_non_alphanumeric': 0.036384976525821594, 'fraction_numerical': 0.035211267605633804, 'mean_word_length': 5.338289962825279, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Long‐term prognostic value of a normal dipyridamole thallium‐201 perfusion scan

In a 4‐year period, 84 patients who were referred for a dipyridamole thallium‐201 stress test to rule out significant coronary artery disease had normal scans. A dipyridamole study was recommended instead of exercise because of arthritis, severe obesity, peripheral vascular disease, pulmonary disease, other chronic illnesses, or combinations of these problems. All patients had three‐view (i.e., anterior, shallow left anterior oblique, and steep left anterior oblique) planar thallium‐201 imaging 10 minutes and 3.5 hours after administration of 0.6 mg/kg of intravenous dipyridamole. The patients were followed for 42±13 (range 1–58) months to document the cardiac event rate. Of the 84 patients with normal results, 14 died during the follow‐up period from noncardiac causes. Three other patients died 29–51 months after the test due to an acute myocardial infarction, a probable acute myocardial infarction, and sudden cardiac death, respectively. Of the survivors, 5 suffered an acute myocardial infarction 28–50 months after the dipyridamole thallium scan and 1 had coronary artery bypass grafting due to increasing angina pectoris 58 months after the scan (overall cardiac event rate of 0.4% per year). Of the remaining 61 patients, 39 (64%) were asymptomatic, 20 (33%) had the same symptoms they had at the time of testing without significant deterioration, while 2 patients (3%) had deterioration of their chest pains but no cardiac complication. Thus, in this group of patients, a normal dipyridamole thallium‐201 perfusion scan predicted a good cardiovascular outcome for at least 24 months following the test.