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Can QT interval prolongation or dispersion detected in a positive exercise ECG test predict critical coronary artery
Abdullah Orhan Demirtaş1, Orsan Deniz Urgun1
1Cardiology Department, Adana Health Practice and Research Center, Health Science University, Adana, Turkey.
Insights
Prolonged QT interval and QT dispersion during recovery after exercise electrocardiography predict critical coronary artery disease. These findings can improve the accuracy of exercise testing for diagnosing coronary artery disease.
Area of Science:
- Cardiology
- Diagnostic Imaging
- Electrocardiography
Background:
- Exercise electrocardiography (EET) has low specificity for coronary artery disease (CAD).
- QT interval prolongation and dispersion are potential indicators of CAD and arrhythmia, but under-investigated in EET.
- This study aimed to assess if QT parameters in positive EET predict critical CAD.
Purpose of the Study:
- To investigate the predictive value of QT interval prolongation and QT dispersion (QT disp) during exercise electrocardiography (EET) for critical coronary artery disease (CAD).
- To determine if these electrophysiological parameters can enhance the clinical accuracy of EET in diagnosing significant CAD.
Main Methods:
- 192 patients with positive EET were analyzed.
- QT, corrected QT interval (QTc), and QT disp were measured before, during, and after EET.
- Critical CAD (≥70% coronary artery occlusion) was confirmed via coronary angiography.
Main Results:
- Critical CAD patients showed significantly higher recovery QTc, peak QT disp, and recovery QT disp compared to non-critical CAD patients.
- Recovery QTc and recovery QT disp were identified as independent predictors of critical CAD.
- A recovery QTc cutoff of 404 ms achieved 90% sensitivity for diagnosing critical CAD.
Conclusions:
- Prolonged QTc and QT dispersion during the recovery phase of EET are significant predictors of critical CAD.
- Incorporating these QT parameters can potentially improve the diagnostic accuracy of EET for coronary artery disease.
Introduction:
Exercise electrocardiography (EET) is frequently used in coronary artery disease, but the specificity of this test is very low. In the literature, parameters such as QT prolongation and QT dispersion which show coronary artery disease and arrhythmia were not sufficiently investigated using EET. The aim of this study was to investigate whether QT interval prolongation or dispersion (QT disp) in a positive EET test could predict critical coronary artery disease (CAD).
Material And Methods:
Patients with a positive exercise test were included in the study. Data regarding QT, QTc (corrected QT interval) and QT disp values before, during and after EET were noted. Critical coronary artery occlusions (≥ 70%) was recorded from coronary angiographic images. Patients were divided into two groups (critical CAD and non-critical CAD).
Results:
A total of 192 patients were found to be eligible for the study. There were 126 patients in the non-critical CAD group (group 1) and 66 patients in the critical CAD group (group 2). Recovery QTc, peak QT disp, and recovery QT disp were significantly increased in group 2 (p < 0.001 for each). Also, target heart rate (p = 0.012), basal systolic blood pressure (p = 0.005) and diastolic blood pressure (p < 0.001) were significantly higher in group 1. Recovery QTc (OR = 1.051) and recovery QT disp (OR = 1.117) were determined as the independent predictors for critical CAD. The ROC analysis results indicated that critical CAD could be diagnosed with 90% sensitivity when the recovery QTc cut-off value was set as 404 ms.
Conclusions:
In patients with positive EET, prolonged QTc and QT disp values measured during the recovery period would predict critical CAD. Thus, the clinical accuracy of EET may be enhanced.
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