PATHOLOGIC Q-WAVE ON ECG AS A PREDICTOR OF NON-VIABLE MYOCARDIUM IN POST-MYOCARDIAL INFARCTION PATIENTS
Keywords:Pathologic Q-wave, Single photon emission computed tomography (SPECT), non-viable myocardium
OBJECTIVE: To determine the diagnostic accuracy of pathologic Q wave on ECG in predicting the presence of non-viable myocardium taking SPECT as gold standard.
MATERIALS AND METHODS: This validation study enrolled 150 patients of myocardial infarction referred to the Department of Nuclear Medicine for evaluation of myocardium viability with EF ?50%, having age 30-70 years. The study duration was Oct-2019 to April-2020. 12 lead ECG was done to determine pathologic Q-waves on ECG. After ECG, all patients underwent SPECT scanning. SPECT was performed using Tc99 scanning protocol. Myocardium was considered non-viable if >10% of the LV myocardial tissue was found non-viable.
RESULTS: Mean age was 53.57±11.41 years. There were 124 (82.7%) male and 26 (17.3%) female patients. On ECG, pathologic Q-wave was present in 87 (58%) patients, while non-viable myocardium on SPECT was present in 110 (79.0%) patients. The sensitivity of Q-wave was 71.8%, specificity was 80.0%, PPV was 90.8% and NPV was 50.8%. Kappa statistics value was 0.43 which indicate moderate agreement.
CONCLUSION: Pathologic Q-wave on 12 lead ECG have average sensitivity and specificity for the diagnosis of non-viable myocardium. So in facilities where SPECT imaging is available, the consultant should rely on the SPECT findings instead of pathologic Q-waves for determination of irreversible myocardial scarring.
KEYWORDS: Pathologic Q-wave, Single photon emission computed tomography (SPECT), non-viable myocardium.