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

Abstract

BackgroundPatients with ST-elevation acute myocardial infarction attending primary care centers, treated with pharmaco-invasive strategy, are submitted to coronary angiography within 2-24 hours of fibrinolytic treatment. In this context, the knowledge about biomarkers of reperfusion, such as 50% ST-segment resolution is crucial.ObjectiveTo evaluate the performance of QT interval dispersion in addition to other classical criteria, as an early marker of reperfusion after thrombolytic therapy.MethodsObservational 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.ResultsWe 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.ConclusionOur data suggest that regional QTcD is a promising non-invasive instrument for detection of reperfusion in the culprit artery 60 minutes after thrombolysis.

Infarto agudo do miocárdio: Do diagnóstico à intervenção

“…O ECG é uma demonstração gráfica da atividade elétrica do coração pelo tempo, que é mensurado através da colocação de eletrodos em pontos específicos (Dotta et al, 2018).…”

“…A restauração da irrigação em uma região isquêmica poderá ocasionar danos devidos à restauração do fluxo sanguíneo, denominados lesões de reperfusão. Contraditoriamente, o retorno sanguíneo causa lesão tecidual adicional, denominada lesão por reperfusão (Dotta et al, 2018) Os mecanismos moleculares e celulares decorrentes da lesão de reperfusão são diversos e incluem estresse oxidativo, alteração da membrana mitocondrial, dano mitocondrial, sobrecarga de cálcio, hipercontração, apoptose, resposta inflamatória, ativação plaquetária e disfunção endotelial. Que poderão ocasionar as seguintes manifestações clínicas: lesão por reperfusão letal, disfunção microvascular, atordoamento miocárdico e arritmias por reperfusão (van der Pol et al, 2019).…”

Acurácia da Redução do Segmento-ST Pós-Trombólise como Preditor de Reperfusão Adequada em Estratégia Fármaco-Invasiva

“…Embora com número pequeno de pacientes avaliados, estes dados sugerem a dQT-Reg um instrumento promissor na identificação não invasiva de reperfusão. 38 É clinicamente reconhecida a capacidade em predição do alívio dos sintomas isquêmicos durante a reperfusão. 39 No entanto, este relato fica sujeito às influências idiossincráticas, assim como possível mascaramento dos sintomas pela utilização de fármacos (nitratos, analgesia, sedação).…”

Rediscovering Clinical Utility of QT Dispersion: A Long-Forgotten Parameter

“…This inhomogeneous as the area can form a substrate for reentrant arrhythmias initiation. Prolongation of the repolarization phase can also induce arrhythmia through the after depolarization mechanism [13].…”

“…Several treatments have been correlated with QT dispersion improvement, e.g., reperfusion therapy with the thrombolytic agent, revascularization with the percutaneous coronary intervention, or coronary artery bypass grafting. Restoration of epicardial coronary flow may improve stunned myocardium, reduce scar tissue formation, and induce homogenous repolarization on the myocardial [13][14][15]. Betablocker treatment in a patient with the long-QT syndrome and candesartan for heart failure and hypertension has also decreased QT dispersion [16].…”