modality of choice, since MPI does not appear to add significant value if thestress ECG is normal. This finding applies mainly to the low to intermediaterisk group of female patients who have normal baseline ECG, normalLVEF, and normal exercise capacity.

29.04PREVALENCE AND PREDICTORS OF CORONARY ARTERYDISEASE IN PATIENTS WITH LEFT BUNDLE BRANCH BLOCKV Jeevanantham, K Manne, JM Haley, J Thomas, PK Mathew, DH HsiCardiology Division, Department of Medicine, Park Ridge Hospital,Unity Health System, Rochester, New York, USABackground: Studies looking at the prevalence of coronary artery disease(CAD) in patients with left bundle branch block (LBBB) have reportedvaried results (9 to 48%). The diagnosis of myocardial ischemia in patientswith LBBB is often a challenge. Understanding the prevalence of CAD andrisk predictors of CAD in patients with LBBB will assist clinical decision-making in the evaluation for ischemia in this population.Methods: We conducted a cross sectional study from June 2005 to February2006 in patients who underwent stress testing and myocardial perfusionimaging (MPI). Seventy-nine patients with LBBB underwent adenosine ordypyridamole gated MPI and 538 patients with normal baseline EKGunderwent treadmill stress testing and gated MPI. All patients had similarindications to assess for myocardial ischemia. The data on demographicvariables and risk factors for CAD were collected.Results: In patients with LBBB, the average age was 70 � 12yrs, 86.7%had hypertension, 69.3% had hyperlipidemia, 58.7% were women,25.3% had diabetes, 22.7% had peripheral vascular disease, and 16% hada history of smoking. MPI was positive for myocardial ischemia orinfarct in 62.7% of patients with LBBB compared to 25.1% in patientswith normal baseline EKG (p �0.001). Positive MPI tests were presentin 93.3% of patients having LBBB and left ventricular ejection fraction(LVEF) �50%, compared to only 68.3% of patients with normal ECGand LVEF �50% (p 0.008). In the MPI negative group, the mean LVEFwas similar in patients with and without LBBB [(60.39 � 9.4 vs 61 �7.2), p 0.673]. Multivariate regression analysis revealed significantpredictors of CAD being LVEF �50% [OR 8.4, p �0.001], LBBB [OR5.4, p �0.001], male gender [OR 3.2, p � 0.001], and hyperlipidemia[OR 1.59, p 0.04].Conclusions: In patients with LBBB, the probability of CAD is highbased on MPI findings. Patients with both LBBB and LVEF �50% areat particularly high risk. In patients with LBBB undergoing evaluationfor myocardial ischemia, we propose consideration of LVEF assessmentwhich, if found to be less than 50%, warrants proceeding directly tocoronary arteriography rather than to additional noninvasive testing.This new diagnostic strategy needs to be validated in further largeprospective studies.

29.05PREDICTORS OF NORMAL MYOCARDIAL PERFUSION IMAGINGIN PATIENTS ADMITTED TO AN EMERGENCY DEPARTMENTCHEST PAIN UNITTM Maddox, KJ Reid, JS Corriel, MJ HenzlovaMount Sinai Medical Center, New York, NYBackground: Emergency department chest pain units (CPU) haveemerged as an efficient and safe method for rapidly triaging patients withchest pain and without evidence of myocardial necrosis into low,intermediate, and high risk for acute coronary syndrome (ACS). Wesought to define clinical and exercise stress variables of these patientsthat would accurately predict normal results of myocardial perfusionimaging, and thus avoid further time and exposure to radiation prior tosafe discharge from the ED chest pain unit.Methods: We retrospectively evaluated 514 consecutive patients withoutknown CAD from the Mount Sinai ED chest pain unit between February2004 and March 2005 who received stress testing with nuclear perfusionimaging. 283 (55.1%) patients underwent exercise stress testing, 231(44.9%) patients underwent pharmacological stress testing, and allreceived Tc-99m gated SPECT myocardial perfusion imaging. For theexercise stress test patients, demographic (age, sex, race, insurancestatus), clinical (hypertension, hyperlipidemia, diabetes, family historyof CAD, PVD, smoking, BMI, resting heart rate, resting blood pressure,normal/abnormal resting EKG), and exercise (�/� 5 METS and Duke

treadmill score) variables were collected and analysed by logisticregression to determine predictors of abnormal perfusion imaging.Results: Compared to pharmacologic stress test patients, exercise stresstest patients were younger (50.2 �/� 10.1 vs. 60.7 �/�13.8 years),more likely male (29.1% vs. 47.5%), non-Hispanic (61.9% vs. 51.1%),uninsured (12.1% vs. 4.8%), non-hypertensive (55.5% vs. 34.2%), andnon-diabetic (90.5% vs. 77.9%). Thirteen (4.6%) had low pretestprobability for CAD, 208 (73.5%) had intermediate probability, and 62(21.9%) had high probability. Among exercise stress test patients,significant predictors of normal perfusion imaging were female sex (OR6.59; 95% C.I. [2.31, 18.87]), achieving � 5 METs during ETT (OR3.92; 95% C.I. [1.13, 13.57]), and a higher Duke score (OR 1.14 per 1point higher score; 95% C.I. [1.05, 1.25]). The c statistic for the logisticregression model was 0.81, indicating excellent predictive power.Conclusions: Female sex, �5 METS exercise capacity, and higher Duketreadmill scores accurately predict normal stress perfusion results inpatients without known CAD admitted to the emergency departmentCPU. Patients with these characteristics may not require the additionaltime and radiation exposure inherent to nuclear perfusion imaging.

29.06ROLE OF MYOCARDIAL PERFUSION IMAGING IN DETECTION OFOCCULT MYOCARDIAL ISCHEMIA IN VULNERABLE PATIENTSS AzabFaculty of Medicine, Alexandria, EgyptObjectives: Cardiovascular diseases, of which coronary heart disease is themost common, are the main cause of death in middle-aged and older adults.The term “cardiovascular vulnerable patient” is proposed to define subjectssusceptible to an acute coronary syndrome or sudden cardiac death based onplaque, blood, or myocardial vulnerability. Aim: to investigate the relationof different risk factors (Hypertension, Diabetes, Hyperlipidemia, Over-weight, Smoking, Hyper-homocysteinemia) of coronary artery disease(CAD) to the findings from thallium-201 SPECT study, to determine itsincremental prognostic value over pre-SPECT information, and its ability torisk-stratify patients in a clinically relevant fashion.Results: Fifty patients represented with chest pain, with normal restingelectrocardiogram and more than two risk factors. There were 32 (64%)males and 18 (36%) femalesBaseline data

N 50 Serum HDLcholesterol (mg/dl)

38 � 12

Sex (M/F) 32/18 Serum LDLcholesterol (mg/dl)

171 � 48

Age 45 � 13 Serum triglyceride(mg/dl)

185 � 22

BMI (Kg/m2) 32.7 � 2.3 Diabetes 22# of risk factors

per patient2.9 � 1.5 Plasma homocysteine

(mmol/L)24.35 � 2.7

Family historyof CAD

27 Low risk 14

Smoking 30 (60%) Moderate risk 25Hypertension �150/90 mmHg 38 High risk 11Serum cholesterol

(mg/dl)248 � 35

Detection of myocardial ischemia:Exercise stress test: Among 50 subjects undergoing tread-mill stress test,29 had positive stress test, nine were females (9/18) 50%, 20 were males(20/32) 62.5%. The average metabolic equivalent (MET) level was 10 � 3in men and 7 � 3 in women (P�0.005)Thallium perfusion study: An abnormal scintigram occurred in 14females (77.7%), 28 males 87.5%. Among the 42 subjects with abnormalscan, there were 76 perfusion defects 19 subjects had single defects, 12subjects had two separate vascular territories and 11 subjects had defectsin three vascular territories. All 76 defects were reversible, 32 were mild,24 were moderate, and 20 were severe. In those with abnormal exercisestress test and perfusion scan, defects were more often moderate orsevere and were more often in 2 vascular distributions. The rate ofthallium-201 perfusion abnormalities in no risk, low risk, moderate risk,and high risk groups were 48.1%, 70.6 %, and 89% respectively,showing significant difference between them (X2� 49.6, P �0.0001).Using a univariate linear regression analysis, it was found that Total

Journal of Nuclear Cardiology Abstracts S27Volume 13, Number 4;S26-S36