The comparison in reduction of QT dispersion after primary percutaneous coronary intervention according to existence of thrombectomy in ST-segment elevation myocardial infarction

Abstract

Background: Primary percutaneous coronary intervention (PPCI) is the standard treatment in patients with ST-segment elevation myocardial infarction (STEMI). Thrombectomy devices are used to remove thrombus or to prevent embolization of thrombus and plaque during PPCI. QT dispersion (the difference between maximal and minimal QT interval calculated on a standard 12-lead electrocardiogram) represents the regional nonuniformity of ventricular repolarization. It may reflect early coronary reperfusion in reducing electrophysiological instability by decreasing QT dispersion in the recovery phase after acute STEMI.

Hypothesis: Our aim was to show whether an additional effect of thrombectomy on reducing QT dispersion will be seen in patients undergoing PPCI for STEMI.

Methods: The study population included 80 consecutive patients who were admitted to the hospital within 12 hours after the onset of acute STEMI and angiographic evidence of intraluminal thrombus in the infarct-related artery. Patients with atrial fibrillation or flutter, intraventricular conduction abnormalities, pre-excitation, cardiogenic shock, cardiomyopathy, ventricular hypertrophy, and severe valvular heart disease were excluded from the study.

Results: There were no significant differences between groups regarding gender, age, cardiovascular risk factors, and time from symptom onset to treatment, except for smoking, which was much higher in the PPCI plus thrombectomy group. Infarct-related artery distribution (left anterior descending artery [LAD] to non-LAD), and neither the rate of balloon predilatation nor stent implantation were different between groups. Successful coronary patency was achieved in each case. QT interval measurements were similar between groups at admission. However, at 24 hours, QT and QTc dispersions were less in the PPCI plus thrombectomy group (41 ± 9 vs 33 ± 7 ms, P < 0.05 and 45 ± 8 vs 35 ± 7 ms, P = 0.03, respectively), but not in the other QT interval measurements. When patients were divided into 2 groups according to infarct-related artery (LAD and non-LAD groups), QT interval measurement parameters did not show any significant differences.

Conclusions: Thrombectomy additional to PPCI helps more effective reperfusion at the microvascular level and provides additional prognostic information.