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Relation of QT-interval variability to ventricular arrhythmias during percutaneous transluminal coronary angioplasty
A Kajiyama1, D Saito, T Murakami
1Department of Cardiology, Iwakuni National Hospital, Japan.
Insights
Increased QT interval dispersion during percutaneous transluminal coronary angioplasty (PTCA) is linked to ventricular arrhythmias. This suggests variations in ventricular repolarization contribute to arrhythmias during PTCA procedures.
Area of Science:
- Cardiology
- Electrophysiology
- Medical Procedures
Background:
- Percutaneous transluminal coronary angioplasty (PTCA) can induce ventricular arrhythmias.
- The role of QT interval dispersion in these arrhythmias requires further investigation.
Purpose of the Study:
- To investigate the relationship between QT interval dispersion and PTCA-induced ventricular tachyarrhythmias.
- To determine if variations in ventricular repolarization contribute to arrhythmias during PTCA.
Main Methods:
- Studied 22 patients with significant Left Anterior Descending (LAD) artery stenosis undergoing PTCA.
- Continuously monitored standard 12-lead ECG during the procedure.
- Analyzed corrected QT (QTc) interval dispersion, including maximum difference (deltaQTc) and standard deviation (QTcSD).
Main Results:
- Averaged QTc and QTac intervals did not significantly change during PTCA.
- Seven patients developed ventricular arrhythmias during PTCA.
- In patients with arrhythmias, deltaQTc and QTcSD significantly increased during PTCA.
- In patients without arrhythmias, deltaQTc and QTcSD decreased during PTCA.
Conclusions:
- Increased QT interval dispersion is associated with percutaneous transluminal coronary angioplasty-induced ventricular arrhythmias.
- Variations in ventricular repolarization, indicated by QT dispersion, play a role in the development of these arrhythmias.
Abstract:
The present study investigated the role of the dispersion of QT interval in percutaneous transluminal coronary angioplasty (PTCA)-induced ventricular tachyarrhythmias. Patients with effort angina without a previous myocardial infarction (n = 22), who had single-vessel disease of the anterior descending coronary artery (LAD), underwent PTCA if the coronary lesion was 75% or more stenosed in segment 6 or 7 of the LAD. The standard 12-lead ECG was continuously recorded during the procedure. Averaged QTc and QTac intervals, where QTac was the interval from the beginning of QRS complex to the nadir of T wave corrected by Bazett's formula, did not change significantly during PTCA. Of the 22 patients, 7 showed ventricular arrhythmias during PTCA. The maximum difference (deltaQTc) and the standard deviation (QTcSD) of the corrected QT interval in the standard 12-lead ECG increased significantly during PTCA in the 7 patients with ventricular arrhythmias, whereas they decrreased in the 15 patients without ventricular arrhythmias. deltaQTac and QTacSD were not affected by PTCA regardless of ventricular arrhythmias, which shows that the increases in the variation of the ventricular repolarization process play a role in PTCA-induced ventricular arrhythmias.