[Effect of percutaneous coronary intervention on QT dispersion and its clinical implication in patients with acute myocardial infarction].

Objective: To observe the effects of percutaneous coronary intervention (PCI) on QT dispersion (QTd) and explore its clinical significance in patients with acute myocardial infarction (AMI).

Methods: The electrocardiograms recorded before and one day after PCI were analyzed in 138 patients with AMI. The duration from the onset of AMI to PCI operation was less than 6 h in 72 patients and 6 to 12 h in the other patients. All the patients underwent emergency percutaneous transluminal coronary angioplasty and subsequent coronary stenting. QT intervals, QTd, and heart rate-corrected QT intervals (QTc) and QTd (QTcd) were measured and calculated.

Results: In both patient groups receiving PCI with delay shorter and longer than 6 h after AMI, QT and QTc after PCI were not significantly different from that before PCI, but the QTd and QTcd were remarkably decreased after PCI (all the P <0.01). Moreover, the QTd and QTcd in the patients with delay of PCI less than 6 h were significantly shorter than those in patients the with greater-than-6-hour delay (P<0.05), and the inhospital mortality was 4.2% and 7.6% in the two groups, respectively (P=0.394).

Conclusion: Successful PCI may notably reduce QTd in the patients with AMI, whose earlier performance usually produces better effects.