ABC | Volume 112, Nº1, January 2019

Original Article Dotta et al Regional QT dispersion as predictor of reperfusion Arq Bras Cardiol. 2019; 112(1):20-29 Table 5 – Electrocardiographic parameters evaluated before and after tenecteplase (TNK) administration in patient with TIMI 3 and Blush grade 3 [T3B3 (+)] and patients with TIMI < 3 and Blush grade < 3 [T3B3 (-)] in the culprit artery Pre-TNK T3B3 (+) T3B3 (-) p-value N 53 51 QTc (ms), m ± SD 421.56 ± 28.51 423.29 ± 25.77 0.72 QTcD (ms), md (IIQ) 59 (44-82) 59 (43-81) 0.97 Regional QTc (ms), m ± SD 418.86 ± 27.01 423.55 ± 30.41 0.38 Regional QTc (ms), md (IQR) 25 (11.5-40) 29 (18-50) 0.09 Pre –TNK T3B3 (+) T3B3 (-) p-value N 18 24 Regional QTcD (ms), md (IIQ) 23 (11.75-39.25) 25 (18-46) 0.65 Post –TNK T3B3 (+) T3B3 (-) p-value N 53 51 QTc (ms), m ± DP 426.90 ± 43.98 431.94 ± 27.47 0.42 QTcD (ms), md (IIQ) 62 (49-75) 66 (40-91) 0.62 Regional QTc (ms), m ± DP 430.53 ± 44.01 424.14 ± 36.12 0.19 Regional QTcD (ms), md (IIQ) 33 (20-59) 42 (19-63) 0.71 Post –TNK T3B3 (+) T3B3 (-) p-value N 18 24 Regional QTcD (ms), md (IIQ) 38 (24.25-73) 42 (21-61) 0.05 Data expressed as mean and standard deviation (m ± SD), median and interquartile range (md and IQR). QTc: mean QT interval, corrected for heart rate in the 12 leads; QTcD: dispersion of the QTc interval in the 12 leads; regional QTc: mean regional QTc in anterior wall infarction; regional QTcD: regional QTc dispersion in anterior wall infarction. Continuous numerical variables were compared by the Student’s t-test for independent samples or the Mann-Whitney test, as appropriate. 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 in this cohort of patients treated with pharmaco-invasive strategy. 1.0 1.0 0.8 0.8 0.6 0.6 0.4 0.4 0.2 0.2 0.0 1.0 0.8 0.6 0.4 0.2 0.0 1.0 0.8 0.6 0.4 0.2 0.0 0.0 1.0 0.8 0.6 0.4 0.2 0.0 1.0 0.8 0.6 0.4 0.2 0.0 AUC: 0.81 (0.72-0.89); 95% IC. p < 0.001 AUC: 0.84 (0.73-0.95); 95% IC. p < 0.001 AUC: 0.87 (0.78-0.96); 95% IC. p < 0.001 (a) ST-segment resolution in T3B3(+) group (b) Increase in regional QTcD in T3B3(+) group (c) ST-segment resolution and regional QTcD in T3B3(+) group Sensitivity Sensitivity Sensitivity 1 – Specificity 1 – Specificity 1 – Specificity and the analysis of QTcD in precordial leads only. Another study involving 36 patients did not show any difference in QTcD in the group with criterion for reperfusion on the first day of AMI. Interestingly, the authors observed a decrease in QTcD since the second day of thrombolysis, particularly in the group with anterior wall myocardial infarction. 30 Another study also reported decreased QTcD six months after AMI. 31 Our findings indicate an increase in QTcD on ECG 60 minutes after fibrinolysis in patients with angiographic findings of complete vascular and tissue revascularization (TIMI flow 25