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Volume 112, Nº 1, January 2019


DOI: http://www.dx.doi.org/10.5935/abc.20180239


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

Gabriel Dotta

Francisco Antonio Helfenstein Fonseca

Maria Cristina de Oliveira Izar

Marco Tulio de Souza

Flavio Tocci Moreira

Luiz Fernando Muniz Pinheiro

Adriano Henrique Pereira Barbosa

Adriano Mendes Caixeta

Rui Manoel Santos Póvoa

Antônio Carlos Carvalho

Henrique Tria Bianco

Dr. Gabriel Dotta


Background: Patients with ST-elevation acute myocardial infarction attending primary care centers, treated with pharmacoinvasive strategy, are submitted to coronary angiography within 2-24 hours of fibrinolytic reatment. In this context, the knowledge about biomarkers of reperfusion, such as 50% ST-segment resolution is crucial.

Objective: To evaluate the performance of QT interval dispersion in addition to other classical criteria, as an early marker of reperfusion after thrombolytic therapy.

Methods: Observational study including 104 patients treated with tenecteplase (TNK), referred for a tertiary hospital. Electrocardiographic analysis consisted of measurements of the QT interval and QT dispersion in the 12 leads or in the ST-segment elevation area prior to and 60 minutes after TNK administration. All patients underwent angiography, with determination of TIMI flow and Blush grade in the culprit artery. P-values < 0.05 were considered statistically significant.

Results: We found an increase in regional dispersion of the QT interval, corrected for heart rate (regional QTcD) 60 minutes after thrombolysis (p = 0.06) in anterior wall infarction in patients with TIMI flow 3 and Blush grade 3 [T3B3(+)]. When regional QTcD was added to the electrocardiographic criteria for reperfusion (i.e., > 50% ST-segment resolution), the area under the curve increased to 0.87 [(0.78-0.96). 95% IC. p < 0.001] in patients with coronary flow of T3B3(+). In patients with ST‑segment resolution >50% and regional QTcD > 13 ms, we found a 93% sensitivity and 71% specificity for reperfusion in T3B3(+), and 6% of patients with successful reperfusion were reclassified.

Conclusion: Our data suggest that regional QTcD is a promising non-invasive instrument for detection of reperfusion in the culprit artery 60 minutes after thrombolysis. (Arq Bras Cardiol. 2019; 112(1):20-29)

Keywords: ST Elevation Myocardial Infarction; Electrocardiography; Myocardial Reperfusion; Percutaneous Coronary Intervention; Biomarkers.