Effects of ischemia on repolarization in patients with single and multivessel coronary disease
Dalia Giedrimiene1, Satyendra Giri, Arnoldas Giedrimas
1Hartford Hospital Division of Cardiology, Hartford, Saint Joseph College, Department of Biology, West Hartford, Connecticut, USA.
Insights
QT dispersion (QTd) decreases significantly after successful angioplasty in acute myocardial infarction (MI) patients. This reduction in QTd indicates improved cardiac electrical stability, regardless of coronary artery disease severity.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Imaging
Background:
- QT dispersion (QTd) is a measure of cardiac electrical instability.
- Acute myocardial infarction (MI) poses significant risks due to potential electrical disturbances.
- Coronary artery disease (CAD) severity can impact cardiac function and electrical properties.
Purpose of the Study:
- To investigate the relationship between QT dispersion and the number of obstructed coronary arteries (CAs) in acute MI patients undergoing angioplasty.
- To assess the impact of successful reperfusion on QT dispersion post-angioplasty.
- To evaluate the influence of left ventricular ejection function on QT dispersion.
Main Methods:
- Coronary angiography to identify infarct-related CAs in 141 acute MI patients.
- Percutaneous angioplasty performed on patients with successful reperfusion defined as TIMI III flow.
- QTd measured using 12-lead electrocardiograms before and after angioplasty, at 24 hours, and 3 days.
Main Results:
- Prolonged QTd was observed at baseline in all patients with ischemia.
- Successful reperfusion (n=98) led to a trend of decreasing QTd immediately and at 24 hours, with significant decrease at 3 days.
- No significant change in QTd was noted in patients without reperfusion; however, QTd increased in acute ischemia cases regardless of vessel disease extent.
Conclusions:
- Successful angioplasty significantly reduces QT dispersion in acute MI patients, suggesting improved electrical stability.
- QTd reduction is independent of the number of obstructed coronary arteries, highlighting the benefit of reperfusion.
- QTd may serve as a valuable indicator of reperfusion success and electrical recovery post-MI.
Abstract:
To evaluate if QT dispersion (QTd) may be affected by the number of obstructed coronary arteries (CAs) in patients with acute myocardial infarction (MI) and undergoing angioplasty, and to evaluate if QTd may be affected by ejection function of the heart. The infarct related CA was identified by coronary angiography in 141 patients (97 men, mean age 61.6 +/- 12.9 years) with acute MI undergoing percutaneous angioplasty. Successful reperfusion was defined as TIMI III flow with < 20% residual stenosis. QTd, calculated by subtracting the shortest from the longest QT interval on 12-lead electrocardiograms, was examined immediately before and after angioplasty, at 24 hours, and 3 days after angioplasty. Successful reperfusion was achieved in 98 (69.5%) patients. Prolonged QTd at baseline was found in all patients with ischemia. A trend toward a decrease in QTd was observed immediately after angioplasty and at 24 hours, and a significant decrease at 3 days in patients with successful reperfusion regardless of the number of occluded CAs. There was no change in QTd found in patients with no reperfusion. An increase in QTd was observed in patients with acute ischemia due to single or multivessel disease.
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