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SUMMARY Myocardial imaging with intravenous thallium-201 ("'TI) was performed at rest and following maximal treadmill exercise in 101 patients with suspected coronary artery disease. Results were interpreted from Polaroid scintiphotos by three independent observers with complete interobserver agreement in 79%. Of 25 patients with no or insignificant coronary artery disease (< 50% diameter stenosis), one (4%) had a resting 20'TI image defect, one (4%) had an exercise '°'TI defect, none had an ECG Q wave, and four (16%) had exercise ST-segment depression. Among 76 patients with coronary artery disease (2 50% diameter stenosis), 58 (76%) had a defect on either the rest or exercise IO'TI image. The proportion of patients with an exercise image defect (50/76, 66%) was greater than MYOCARDIAL IMAGING following the intravenous or intracoronary injection of radionuclides provides a useful clinical method for the detection of prior myocardial infarction1' 2 and stress-induced regional myocardial ischemia.3-5 Of the various radiopharmaceuticals (tagged particles, 43K, 81Rb, and 129Cs) available, all have had significant limitations. The injection of tagged particles is strictly invasive; 43K and 81Rb provide relatively poor myocardial-to-background ratios,6 necessitate special whole body shielding for use with scintillation cameras,4 5 and have limited availability; myocardial uptake of '29Cs is not sufficiently rapid to detect transient myocardial ischemia induced by exercise stress.7 8 The recent cyclotron production of 201TI by Lebowitz et al.9 10 appears to overcome many of these limitations. Following intravenous injection at rest, myocardial 2"'TI uptake provides diagnostic quality images on currently available scintillation cameras using standard collimation. Myocardial uptake is sufficiently rapid that injection of the isotope during exercise allows detection of stress-induced myocardial ischemia.This study addresses the question: does myocardial imaging at rest and following maximal treadmill stress enhance the diagnostic sensitivity of rest and stress electrocardiography. The image results are also correlated with findings at coronary arteriography. Materials and MethodsMyocardial imaging was performed in 101 patients with known or suspected coronary artery disease; each patient had cardiac catheterization with selective coronary arteriography and ventriculography, clinical evaluation, and rest-stress electrocardiography. The patients represent an unselected consecutive series having catheterization when "'TI was available. Ninety-four patients were male, seven female; mean age was 50 (range 24 to 68). Patients who had had prolonged rest pain (pre-infarction like angina) were considered unsuitable for exercise testing and were not included in this series. The rest and exercise imaging was completed within 14 days of catheterization in all patients, and there was no evidence for progression of cardiac disease during this period. Patients studied for the investigation of valvular heart disease, cardiomyopathy, or...

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Objectives To compare the outcomes and safety of a rapid access chest pain clinic (RACPC) in Australia with those of a general cardiology clinic. Design Prospective comparison of the outcomes for patients attending an RACPC and those of historical controls. Setting Royal Hobart Hospital cardiology outpatient department. Participants 1914 patients referred for outpatient evaluation of new onset chest pain (1479 patients seen in the RACPC, 435 patients previously seen in the general cardiology clinic). Main outcome measures Service outcomes (review times, number of clinic reviews); adverse events (unplanned emergency department re‐attendances at 30 days and 12 months; major adverse cardiovascular events at 12 months, including unplanned revascularisation, acute coronary syndrome, stroke, cardiac death). Results Median time to review was shorter for RACPC than for usual care patients (12 days [IQR, 8–15 days] v 45 days [IQR, 27–89 days]). All patients seen in the RACPC received a diagnosis at the first clinic visit, but only 139 patients in the usual care group (32.0%). There were fewer unplanned emergency department re‐attendances for patients in the RACPC group at 30 days (1.6% v 4.4%) and 12 months (5.7% v 12.9%) than in the control group. Major adverse cardiovascular events were less frequent among patients evaluated in the RACPC (0.2% v 1.4%). Conclusions Patients were evaluated more efficiently in the RACPC than in a traditional cardiology clinic, and their subsequent rates of emergency department re‐attendances and adverse cardiovascular events were lower.

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