The normalization of negative T waves (TWN) on infarct-related ECG leads (IRLs) in the chronic phase of Q wave anterior MI could be a predictor of residual viability: Imaging study dual isotopes MIBI/Tl-201 SPECT or MIBI SPECT/FDG PET-CT

Objectives Normalization of negative T waves (TWN) on infarct-related ECG leads (IRLs) during exercise tests or dobutamine stress tests in patients with previous myocardial infarction (MI) has been shown to represent the presence of ischemic but viable myocardium within the infarct area The aim of the present study was to verify whether normalization of negative T waves (TWN) on infarct-related ECG leads (IRLs) in the chronic phase of Q wave anterior MI could be a predictor of residual viability in infarct areas or peri-infarct ischemia.

Methods Data was collected on 1329 consecutive patients undergoing stress test and myocardial perfusion scintigraphy between 2001 and 2011. Our study group consisted of 155 patients with Q waves in at least 3 precordial leads, or QS waves in at least 2 leads in the chronic phase of anterior or anteroseptal MI (at least 12 months after the onset of acute MI). Spontaneous TWN (Group A) was defined as negative T waves that became upright (蠅 0.15 mV) in 蠅 2 IRLs. IRLs were defined as leads I, aVL, and V1 to V6. The presence of negative T waves (Group B) was defined symmetric or biphasic, of 蠅 0.15 mV in 蠅 2 IRLs. All patients underwent same-day rest Tl201- stress Tc99m MIBI dual-isotope myocardial perfusion SPECT and 24-hour Tl201 re-injection or stress Tc99m MIBI and cardiac 18F-FDG PET/CT imaging for ischemia and viability analysis. Resting 201Tl imaging was performed 10 min after the intravenous administration of 3 mCi 201Tl. A large-field-of-view rotating gamma camera with a high-resolution, parallel-hole collimator and a 20% window centered at the 76 keV photopeak of 201Tl was used. The cardiac PET protocol was applied according to SNM guideline. The 20-segment model of left ventricle was used as previously described. Each segment was scored using 5-point scoring system: 0=normal, 1=mild, 2=moderate, 3=severe reduction in photon activity, 4= absent of photon activity. The following indexes were calculated for each study: 1) summed rest score (SRS), 2) summed stress score (SSS), and 3) summed re-injection score (SRIS). Ischemi score (=SRS-SSS) and viability score (=SRIS-SRS) were calculated by using previously summed score.

Results We found that the occurrence of TWN in the chronic stage of Q wave anterior MI had marked influence on the sensitivity (82 %), specificity (62 %), and positive predictive value (78 %) for diagnosis of viable myocardium. At scintigraphic examination, 88 patients in Group A had ischemic or viable myocardial segments, whereas four patients in Group B had ischemic or viable myocardium in the anteroseptal or anterior wall. Two of these patients with viable myocardium in Group B had positive T waves in aVR. The occurrence of restored positive T waves in the chronic stage of Q wave anterior MI had marked influence on the sensitivity (82 %), specificity (65 %), positive (78 %) and negative (66 %) predictive values and accuracy (76 %) for diagnosis of viable myocardium. If criteria of restored positive T waves in aVR are added to our criteria, we found that sensitivity (85 %), positive (79 %) and negative (78 %) predictive values and accuracy (80 %) are increased

Conclusions Analysis of TWN on IRLs may be a reliable marker of residual viability and/or persistent peri-infarct ischemia in patients with chronic stage Q wave anterior MI. However, this parameter was not replace to the scintigraphic imaging with MIBI/Tl-201 dual isotope SPECT or MIBI/FDG PET-CT study.