Abstract 13686: Relationship between Early Reduction of QT Dispersion and Restoration of Myocardial Reperfusion in Patients with Recanalized Anterior STEMI
Backgrounds and Objectives: In patients with ST-segment elevation myocardial infarction (STEMI), it is still unclear whether the acute change in QT dispersion after reperfusion therapy reflects the degree of microvascular reperfusion. The aim of this study was to evaluate the relationship between early reduction of QT dispersion and myocardial reperfusion after recanalizationin patients with anterior STEMI.
Methods and Results: 90 consecutive patients with first anterior STEMI who underwent successful (TIMI-3 flow) primary percutaneous coronary intervention (PCI) within 6 hours after the onset were enrolled in this study, and the corrected QT interval (QTc) and QTc dispersion (cQTd) were measured before and 1 hour after PCI. The ratio of cQTd reduction after PCI (QTd-R) was defined as [(cQTd before PCI - cQTd 1 hour after PCI) / cQTd before PCI] x 100 (%). ST resolution (STR) was indicated by reduction of >=50% in sum of ST segment elevation 1 hour after PCI. QTd-R was significantly correlated with myocardial blush grade (MBG) after PCI (r=0.847, p<0.0001), coronary flow velocity estimated by both TIMI frame count and quantitative coronary angiogram immediately after recanalization (r=0.712, p<0.0001), and peak creatine kinase (r=-0.436, p<0.0001). 46 patients had STR and 44 patients did not. Patients with STR were subdivided into 2 groups according to MBG after PCI: 34 patients with MBG 2 or 3, and 12 patients with MBG 0 or 1. QTd-R was higher (71.6+-10.8 vs 17.2+-16.0%, p<0.0001) in patients with MBG 2 or 3 than in those with MBG 0 or 1. However, there was no significant difference in QTd-R between patients who had STR with MBG 0 or 1 and those without STR. Multivariate analysis showed that QTd-R was the only significant independent factor associated with restoration of myocardial reperfusion, as indicated by MBG 2 or 3 after PCI (odds ratio 1.220, p=0.0076).
Conclusions: These findings suggest that QTd-R closely reflects restoration of myocardial reperfusion as compared with STR in patients with recanalized anterior STEMI.
- © 2012 by American Heart Association, Inc.