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Defective recovery of QT dispersion predicts late cardiac mortality after percutaneous coronary intervention
Marco Zimarino1, Alessandro Corazzini, Alfonso Tatasciore
1Institute of Cardiology and Center of Excellence on Ageing, G. d'Annunzio University, Chieti, Ospedale SS. Annunziata, Via dei Vestini, 30, Chieti 66013, Italy.
Insights
A decrease in corrected QT dispersion (cQTD) after percutaneous coronary intervention (PCI) indicates improved repolarization. However, a failure of cQTD to recover post-PCI predicts long-term cardiac mortality in patients.
Area of Science:
- Cardiology
- Electrophysiology
- Clinical Research
Background:
- Corrected QT dispersion (cQTD) is proposed as a marker for repolarization inhomogeneity.
- The association between cQTD and cardiac outcomes remains debated.
- Understanding cQTD changes after interventions is crucial for predicting patient prognosis.
Purpose of the Study:
- To investigate if changes in cQTD following percutaneous coronary intervention (PCI) can predict long-term survival.
- To assess the prognostic value of cQTD recovery after PCI.
Main Methods:
- Prospective observational study involving 612 patients undergoing PCI.
- 12-lead ECGs were recorded pre-procedure and 6 hours post-PCI.
- Patients were followed for approximately 49 months to determine cardiac mortality.
Main Results:
- PCI significantly reduced overall cQTD at 6 hours post-procedure (p < 0.001).
- A reduced change in cQTD (ΔcQTD) was an independent predictor of cardiac mortality (HR = 1.497 per 20 ms decrease; p = 0.015).
- Factors like age, diabetes, peak CK-MB, extent of coronary artery disease, and treated lesions also predicted mortality.
Conclusions:
- Corrected QT dispersion (cQTD) generally decreases after PCI.
- A failure in cQTD recovery post-PCI suggests persistent repolarization abnormalities.
- Impaired cQTD recovery is a significant predictor of long-term cardiac mortality.
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.
