Regional QT Interval Dispersion as an Early Predictor of Reperfusion in Patients with Acute Myocardial Infarction after Fibrinolytic Therapy

Figures

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  Figure 1. Distribution of patients by the presence of ST-segment resolution (classical electrocardiographic criteria for reperfusion) and angiographic profile of TIMI flow (1a) or perfusion pattern (TIMI flow and Bulsh grade); in the culprit artery; T3B3 (+): patients with TIMI 3 and Blush grade 3 in the culprit artery; T3B3 (-): patients with TIMI 3 and Blush grade < 3 in the culprit artery (1b).

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  Figure 2. ROC curves for the classical electrocardiographic criterion for reperfusion (ST-segment resolution); regional dispersion of the QT interval, corrected for heart rate (QTc); and ST-segment resolution combined with regional dispersion of the QTc interval in patients with optimal reperfusion profile, i.e., TIMI flow and Blush grades 3 [T3B3 (+)]. (a) In patients with ST-resolution, the area under the ROC curve was 0.81 [(0.72-0.89); 95%CI, p < 0.001) to detect TIMI flow 3 and Blush 3 [T3B3(+)]; (b) increased regional QTc dispersion 60 minutes after thrombolysis resulted in an area under the ROC curve of 0.84 [(0.73-0.95); 95%CI, p < 0.001 to detect T3B3 (+), using a cutoff point of > 13 ms, a 94% sensitivity and a 74% specificity were obtained; (c) increased regional QTcD associated with ST-segment resolution 60 minutes after thrombolysis resulted in an area under the ROC curve of 0.87 [(0.78-0.96); 95%CI, p < 0.001 to detect T3B3 (+). Using a cutoff point of > 13 ms, a 93% sensitivity and a 71% specificity were obtained. Six patients (approximately 6%) could be reclassified based only on electrocardiographic measurements. Validated by angiographic criteria of coronary reperfusion…

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  Figure 3. Behavior of the regional QT interval, corrected for heart rate, in subgroups of patients with failed reperfusion or failed rescue; data expressed as median and interquartile range (m,IQR); QTcD: dispersion of the QTc interval; TNK: tenecteplase; T3B3 (+): patients with TIMI 3 and Blush grade 3 in the culprit artery; T3B3 (-): patients with TIMI 3 and Blush grade < 3 in the culprit artery; Wilcoxon test. *Failed rescue: patients without ST-segment resolution and with optimal coronary and tissue perfusion [T3B3 (+)]; †failed reperfusion: patients with ST-segment resolution, without optimal coronary and tissue perfusion [T3B3 (-)].