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QT dispersion and arrhythmic events in idiopathic dilated cardiomyopathy
1Department of Cardiology, Hospital of the Philipps-University of Marburg, Germany.
Insights
QT dispersion is elevated in idiopathic dilated cardiomyopathy (IDC) patients. While increased QT dispersion was observed in IDC patients with arrhythmic events, it has limited predictive value for arrhythmias.
Area of Science:
- Cardiology
- Electrophysiology
- Heart Disease Research
Background:
- Idiopathic dilated cardiomyopathy (IDC) is a significant cause of heart failure.
- Assessing arrhythmia risk in IDC patients is crucial for clinical management.
- QT dispersion reflects myocardial electrical heterogeneity, a potential marker for arrhythmia risk.
Purpose of the Study:
- To investigate QT dispersion in patients with IDC compared to controls.
- To determine the association between QT dispersion and the occurrence of arrhythmic events in IDC patients.
- To evaluate the predictive utility of QT dispersion for arrhythmia risk stratification in IDC.
Main Methods:
- 12-lead standard electrocardiogram (ECG) was used to measure QT dispersion.
- 107 IDC patients and 100 age- and sex-matched controls were included.
- Prospective follow-up was conducted to identify arrhythmic events (ventricular tachycardia, ventricular fibrillation, sudden death).
Main Results:
- QT dispersion, rate-corrected QT dispersion, and adjusted QTc dispersion were significantly greater in IDC patients than controls.
- During follow-up, 11% of IDC patients experienced arrhythmic events.
- Increased QT dispersion was noted in IDC patients with versus without arrhythmic events (p=0.03), but QTc dispersion measures did not differ significantly.
Conclusions:
- QT dispersion is increased in patients with IDC.
- QT dispersion shows a trend towards being higher in IDC patients who experience arrhythmic events.
- The overlap in QT dispersion values limits its effectiveness for predicting arrhythmia risk in IDC patients.
Abstract:
QT dispersion was measured in the 12-lead standard electrocardiogram in 107 patients with idiopathic dilated cardiomyopathy (IDC) and 100 age- and sex- matched controls without structural heart disease. All 107 study patients with IDC were prospectively followed in order to determine possible associations between QT dispersion and arrhythmic events, i.e., sustained ventricular tachycardia, ventricular fibrillation, or sudden death. QT dispersion, rate-corrected QT dispersion, and adjusted QTc dispersion, which takes account of the number of leads measured, were significantly greater in patients with IDC than in controls. During 13 +/- 7 months follow-up, arrhythmic events occurred in 12 of 107 study patients with IDC (11%). QT dispersion was increased in patients with versus without arrhythmic events during follow-up (76 +/- 17 vs 60 +/- 26 ms; p=0.03). QTc dispersion and adjusted QTc dispersion were not significantly different between patients with and without arrhythmic events (80 +/- 21 vs 75 +/- 35 ms, and 27 +/- 6 vs 24 +/- 10 ms, respectively). Thus, although QT dispersion was increased in patients with IDC and arrhythmic events during follow-up, its usefulness for arrhythmia risk prediction was limited by the large overlap of QT dispersion between patients with and without arrhythmic events.