Agreement between observers with different experience in the interpretation of the stress myocardial perfusion electrocardiogram in SPECT

Abstract

Coronary artery disease (CAD) is the leading cause of death in many countries. Stress electrocardiogram (ECG) is able to detect myocardial ischemia and also has prognostic value, which may be impaired in presence of electrical baseline abnormalities. Stress myocardial single photon emission tomography (SPECT) has recognized good yield in assessment of CAD, requiring independent interpretation of ECG and nuclear images. Purpose To analyze stress ECG interpretation reproducibility among observers with different training level compared to experienced ones and also with SPECT. Method We studied 95 patients under CAD evaluation, mean age 61 ± 9.3 years (range: 42-85), 56% male. We calculated interobserver correlation kappa (κ) between perfusion gated 99mTc-Sestamibi SPECT and exercise ECG. Interpretation was normal/abnormal, presence of necrosis, ischemia or mixed pattern and was performed by under and postgraduate medicine students. Results 49.5% stress ECG and 45% SPECT studies were abnormal at the initial report with 62.1% concordance (κ: 0.24) for normal/abnormal and 58.9% for ischemia (κ: 0.14). Agreement between stress ECG initial report and independent cardiologist was 89.5% (κ: 0.78). The correlation between independent observers and the initial report ranged between 62.1% and 48.4%, for baseline ECG between 41.1% and 90.5% considering normal/abnormal, and between 80% and 93.7% (κ: 0.59-0.87) for the presence of ischemia. Conclusion Stress ECG interpretation presented adequate interobserver reproducibility with greater agreement in the most experienced observers, confirming the importance of training.