Background It has been suggested that corrected QT dispersion (cQTD) provides a measure of repolarisation inhomogeneity; however, the existence of a relationship between cQTD and cardiac outcomes is controversial.
Objective To assess whether changes in cQTD following percutaneous coronary intervention (PCI) predict long-term survival.
Design Prospective observational study.
Setting Single tertiary care centre.
Main outcome measures Cardiac mortality.
Patients 612 patients had a 12-lead ECG recorded before and 6 h after PCI, and were followed-up for 49±10 months.
Results PCI was associated with a significant overall reduction of cQTD at 6 h versus baseline (p<0.001); a reduction in cQTD occurred in 343 patients (56%). During the follow-up, 46 deaths (7.5%) were recorded, 21 of which for non-cardiac and 25 for cardiac causes. At Cox regression analysis, a reduced ΔcQTD (cQTD baseline − 6 h) was an independent predictor of cardiac mortality (HR=1.497; 95% CI 1.081 to 2.075 for each 20 ms decrease; p=0.015), together with age (HR=1.672; 95% CI 1.039 to 2.691 per 10 years increase; p=0.034), diabetes (HR=2.622; 95% CI 1.112 to 6.184; p=0.028), peak CK-MB (HR=1.798; 95% CI 1.063 to 3.039 per each unit increase over normal level; p=0.029), three-vessel coronary artery disease (HR=3.626; 95% CI 1.079 to 12.187; p=0.037) and the number of treated lesions (HR=2.066; 95% CI 1.208 to 3.532; p=0.008). Patients in the lowest tertile of ΔcQTD and having a post-procedural increase of CK-MB had a considerably higher cardiac mortality than the remaining population (14.6 vs 2.4%, p<0.001).
Conclusions cQTD decreases after PCI. A defective cQTD recovery, suggesting the persistence of repolarisation inhomogeneities, predicts long-term cardiac mortality.
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Funding Italian Ministry of the University—to RDC—“G. d'Annunzio” University.
Competing interests None.
Patient consent Obtained.
Ethics approval This study was conducted with the approval of the ethics committee, The University of Chieti, Chieti, Italy.
Provenance and peer review Not commissioned; externally peer reviewed.
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