Author + information
- Ouafa Hamza,
- Abdelmalek Azzouz,
- Omar Ait Mokhtar,
- Nabil Bendaoud,
- Kheireddine Merad and
- Salim Benkhedda
QT dispersion (Qtd) is defined as the difference between the maximal and the minimal values of the QT through the peripheral and precordial leads. It is considered as an arrhythmogenic indice and reflects the inhomogeneity of repolarization.
To investigate the effect of revascularization on corrected QT interval (QTc) and Qtd in acute STEMI patients.
We conducted a prospective study in which patients presenting with acute STEMI who underwent primary percutaneous coronary intervention (PCI) with successful recanalization were enrolled. QTc and QTd were calculated before, 90 minutes and 24 hours after the procedure. ST resolution was estimated at 90 minutes in the worst lead.
82 patients (70 males, 12 females) with a mean age of 56,9 ± 12,7 years were evaluated. The results showed significant reduction in both Qtc (mean 460.81 ± 26.17 ms vs 439.19 ± 18.43 ms ; p < 0,001) and Qtd (mean 60.68 ± 7.57 ms vs 35.78 ± 10.25 ms; p < 0,001) before and 24 hours after primary PCI while no significant difference was noticed in the Qtc (460.81 ± 26.17 vs 454.39 ± 35.89 ; p = 0.19) and Qtd (60.68 ± 7.57 vs 59.17 ± 7.54; p = 0.20) before and 90 minutes after the procedure.
Preprocedural QTd values were similar in patients with and without ST resolution (67 ± 5.77 vs 62 ± 7.53; p = 0.10). 24h after PPCI QTd decreased only in patients with ST resolution (34.61 ± 9.04 vs 58.5 ± 4.12; p <0.001). Multivariate analysis showed that ST resolution was an independent predictor of QTd after successful recanalization (standardized regression coefficient = -0.684; p = 0.004).
In addition to a successful opening of the culprit artery, myocardial reperfusion must be achieved to improve electrical stability and reduce repolarization heterogeneity. Recovery of myocardial electrical homogeneity is not immediate and begins 24 hours after revascularization as assessed by QTc and QTd.