Use of exercise tolerance test and thallium stress test in the diagnosis of ischemic heart disease in soldiers.

OBJECTIVE To determine the role of Exercise Tolerance Test (ETT) and Thallium Stress Test (TST) in the detection of Coronary Artery Disease (CAD) among soldiers. STUDY DESIGN Descriptive study. PLACE AND DURATION OF STUDY This study was conducted at Combined Military Hospital (CMH), Multan, Pakistan, from 2002 to 2004. METHODOLOGY There were 291 male soldiers between ages 30 and 45 years who presented with chest pain and had normal resting ECG. All patients were subjected to ETT. Positive ETT cases had Coronary Angiogram (CA) as the gold standard. Negative cases were subjected to TST. Normal CA cases also had TST to rule out microvascular disease. Those with normal ETT and positive CAD risk factors also had TST. Those with negative TST had CA as service requirement. RESULTS All 291 cases had ETT, 130 cases were found positive, 161 had negative ETT. When CA was done on 130 positive cases, 95 had CAD (true positive, TP) and 35 had normal coronaries (false positive, FP). Out of the 161 negative ETT cases, 128 had normal coronaries (true negative, TN) and 33 had CAD (false negative, FN). TST was conducted on 196 cases, out of which 78 cases were found positive and 118 had negative TST. When subjected to CA, out of 78 positive cases, 30 had CAD (TP) and 48 had normal coronaries (FP). Out of 118 negative TST cases, 115 had normal coronaries (TN) and 3 had CAD (FN). ETT was found to have sensitivity of 74.2%, specificity of 78.5%, Positive Predictive Value (PPV) of 73.1%, Negative Predictive Value (NPV) of 79.5% and test accuracy of 76.6%. TST had sensitivity of 90.9%, specificity of 70.6%, PPV of 38.5%, NPV of 97.5% and accuracy of 74.0%. CONCLUSION TST was found to be more sensitive and less specific than ETT in the diagnosis of CAD.