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In CTOs, observational studies strongly suggest that successful PCI is associated with better clinical outcome, potentially due to less arrhythmic death. PCI CTO may have a significant impact on ventricular conduction properties. We are therefore analyzing the effect of CTO PCI on various electrophysiological parameters reflecting de- and repolarization.
In the EXPLORE trial, patients were shortly after STEMI randomized to either early CTO PCI or conservative treatment. ECGs were performed at several timepoints, and analyses were done using ImageJ. QT dispersion was measured by retracting the lead with the lowest QT interval from the lead with the highest QT interval, reflecting heterogeneity in QT interval duration.
Figure 1 shows the results from 47 successfully treated patients and 66 conservative patients. In both groups QT-interval dispersion decreased, but the overall median delta decrease was higher in the CTO PCI group: -21ms [-44; -1] versus -12.0ms [-37; 8], p=0.112.
Preliminary ECG measurements in the EXPLORE trial show that QT dispersion decreases greatly after CTO PCI. These results suggest that CTO PCI ameliorates ventricular electrophysiological heterogeneity, which could explain the positive effects of CTO PCI found in registries in the past. At TCT 2017, we will present more complete ECG analyses at various timepoints (i.e. directly pre and post CTO PCI), including QTd values, QRS duration, Tp-e interval, and the presence of Q waves and fragmented QRS complexes, as well as the association with LVF at 4 months.
CORONARY: PCI Outcomes