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QT interval dispersion changes according to the vessel involved during percutaneous coronary angioplasty
Harun Kilic1, Enver Atalar, Ozer Necla
1Diskapi Yildirim Beyazit EA Hospital, Department of Cardiology, Ankara, Turkey. hkilic@superposta.com
Insights
Increased QT dispersion (QTd) rises during balloon inflation in coronary artery disease, particularly with left anterior descending and right coronary artery lesions. This marker of myocardial repolarization abnormality is vessel-dependent.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Diagnostics
Background:
- Increased QT dispersion (QTd) is a recognized marker for electrophysiologic abnormalities and elevated mortality risk in coronary artery disease (CAD).
- Understanding QTd dynamics during acute myocardial ischemia is crucial for accurate risk stratification and diagnostic interpretation.
Purpose of the Study:
- To quantify QTd and ST-segment changes during and after intracoronary balloon inflation.
- To investigate the influence of the specific coronary artery involved and inflation duration on QTd variations.
Main Methods:
- Assessed QTd and ST-segment changes in 45 patients undergoing percutaneous transluminal coronary angioplasty (PTCA).
- Measurements were taken immediately before, during (60 seconds), and after (5 minutes) balloon inflation.
- Coronary artery territories (LAD, RCA, Cx) were analyzed for differential effects on QTd.
Main Results:
- A significant increase in mean QTd was observed during balloon inflation (68 ms to 82 ms, p<0.01), with no significant difference at 5 minutes post-deflation compared to baseline.
- QTd elevation during inflation was statistically significant in patients with left anterior descending (LAD) and right coronary artery (RCA) lesions.
- No significant QTd changes were noted in patients with left circumflex (Cx) artery lesions during or after inflation.
Conclusions:
- Acute, reversible myocardial ischemia induced by balloon inflation transiently increases QTd.
- The magnitude of QTd increase is dependent on the specific coronary artery territory affected, primarily LAD and RCA.
- Clinical interpretation of QTd as a marker for myocardial repolarization abnormalities requires consideration of the involved coronary vessel.
Abstract:
Increased QT dispersion (QTd) is a noninvasive marker of an electrophysiologic abnormality associated with high mortality in coronary artery disease. The purposes of this study were to measure changes in QTd and ST-segment changes immediately before, during and after intracoronary balloon inflation and to determine whether the coronary artery vessel involved and/or the duration of inflation affect(s) QTd. A total of 45 patients (32 men, 13 women, mean age 58 +/- 11 years) who were referred for elective percutaneous transluminal coronary angioplasty were included. The mean QT interval dispersions for all patients before the inflation, during the balloon inflation at 60 sec and after the balloon deflation at 5 min were 68 +/- 13 ms, 82 +/- 16 ms and 71 +/- 13 ms, respectively. There was no significant difference between baseline and 5 min after deflation. The increase in QTd during the balloon inflation was significant (p<0.01). There was no significant QTd change in patients with left circumflex artery (Cx) lesions during inflation and after deflation compared with baseline. The differences were statistically significant only in patients with left anterior descending (LAD) lesions and right coronary artery (RCA) lesions at 60 sec during balloon inflation (p=0.001 vs. p=0.04). Acute reversible myocardial ischemia induced by balloon inflation causes an increase in QTd limited to the LAD and RCA vessels. Therefore, when using QTd as a marker of myocardial repolarization abnormality due to acute reversible ischemia, the involved coronary artery vessel must be taken into account.
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