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Effect of coronary angioplasty on QT dispersion
R F Kelly1, J E Parillo, S M Hollenberg
1Section of Cardiology, Rush Medical College, Rush-Presbyterian-St. Luke's Medical Center, Chicago, IL 60612, USA. rkelly@rush.edu
Insights
Coronary angioplasty significantly reduces QT dispersion (QTd), a marker of inhomogeneous ventricular repolarization. This improvement in QTd may lower the risk of serious arrhythmias in patients undergoing the procedure.
Area of Science:
- Cardiology
- Electrophysiology
- Cardiovascular Research
Background:
- Increased QT dispersion (QTd) indicates inhomogeneous ventricular repolarization, a risk factor for arrhythmias and adverse outcomes in heart disease.
- The impact of coronary revascularization on QTd in patients without acute myocardial infarction or ventricular arrhythmias remains unclear.
Purpose of the Study:
- To investigate the effect of successful coronary angioplasty on QT dispersion in patients without ongoing symptomatic ischemia or malignant arrhythmias.
Main Methods:
- QTd was measured in 94 patients before and at 4 and 24 hours after successful angioplasty.
- Patients were selected based on the absence of ongoing symptomatic myocardial ischemia or malignant arrhythmias.
Main Results:
- Successful angioplasty led to a significant decrease in QTd from baseline (434 ± 17 msec) to 4 hours (354 ± 15 msec) and 24 hours (33 ± 14 msec) post-procedure (p < 0.05).
- QTd improved in 64% of patients, worsened in 28%, and remained unchanged in 8%.
Conclusions:
- Coronary angioplasty significantly improves QT dispersion in patients without acute cardiac events.
- The observed improvement in QTd may be attributed to enhanced myocardial perfusion, potentially reducing arrhythmia susceptibility.
Abstract:
Increased QT dispersion (QTmax-QTmin [QTd]) reflects inhomogeneous ventricular repolarization that may provide a substrate for serious arrhythmias and is associated with adverse clinical outcomes in patients with heart disease. Effective treatment of acute myocardial infarction or ventricular arrhythmias may reduce QTd, but the effect of coronary revascularization on QTd in patients without these conditions is unknown. In this study, QTd was measured before and 4 and 24 hours after successful angioplasty in 94 patients without ongoing symptomatic myocardial ischemia or malignant arrhythmias. QTd decreased from 434 +/- 17 msec before angioplasty to 354 +/- 15 msec 4 hours (p < 0.05) and 33 +/- 14 msec 24 hours after angioplasty (p < 0.05). QTd was improved in 64% of patients, worse in 28%, and unchanged in 8%. Thus angioplasty significantly improves QTd. This may reflect increased myocardial perfusion and may be inherently beneficial by reducing the propensity for arrhythmias.