The Morphology of the QT Interval Predicts Torsade de Pointes During Acquired Bradyarrhythmias
| Autor: | Ori Rogowski, Ian Topilski, Michael Glikson, Yitschak Copperman, Sami Viskin, Dan Justo, Marek Hochenberg, Rafael Rosso, Bernard Belhassen |
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| Rok vydání: | 2007 |
| Předmět: |
Male
Pacemaker Artificial congenital hereditary and neonatal diseases and abnormalities Heart disease NOTCHED T WAVES QT interval Risk Assessment Severity of Illness Index Electrocardiography Age Distribution Predictive Value of Tests Reference Values Torsades de Pointes T wave mental disorders medicine Bradycardia Humans cardiovascular diseases Sex Distribution Aged Retrospective Studies Aged 80 and over Analysis of Variance medicine.diagnostic_test business.industry Incidence Corrected qt nutritional and metabolic diseases Middle Aged medicine.disease nervous system diseases Long QT Syndrome Increased risk Logistic Models ROC Curve Anesthesia Case-Control Studies Disease Progression Female business Cardiology and Cardiovascular Medicine Atrioventricular block |
| Zdroj: | Journal of the American College of Cardiology. 49(3):320-328 |
| ISSN: | 0735-1097 |
| DOI: | 10.1016/j.jacc.2006.08.058 |
| Popis: | ObjectivesThe purpose of this study was to define the electrocardiographic (ECG) predictors of torsade de pointes (TdP) during acquired bradyarrhythmias.BackgroundComplete atrioventricular block (CAVB) might lead to downregulation of potassium channels, QT interval prolongation, and TdP. Because potassium-channel malfunction causes characteristic T-wave abnormalities in the congenital long QT syndrome (LQTS), we reasoned that T-wave abnormalities like those described in the congenital LQTS would identify patients at risk for TdP during acquired bradyarrhythmias.MethodsIn a case-control study, we compared 30 cases of bradyarrhythmias complicated by TdP with 113 cases of uncomplicated bradyarrhythmias. On the basis of the criteria used for the congenital LQTS, T waves were defined as LQT1-like (long QT interval with broad T waves), LQT2-like (notched T waves), and LQT3-like (small and late) T waves.ResultsNeither the ventricular rate nor the QRS width at the time of worst bradyarrhythmia predicted the risk of TdP. However, the QT, corrected QT (QTc), and Tpeak–Tend intervals correlated with the risk of TdP. The best single discriminator was a Tpeak–Tend of 117 ms. LQT1-like and LQT3-like morphologies were rare during bradyarrhythmias. In contrast, LQT2-like “notched T waves” were observed in 55% of patients with TdP but in only 3% of patients with uncomplicated bradyarrhythmias (p < 0.001). A 2-step model based on QT duration and the presence of LQT2-like T waves identified patients at risk for TdP with a positive predictive value of 84%.ConclusionsProlonged QT interval, QTc interval, and Tpeak–Tend correlate with increased risk for TdP during acquired bradyarrhythmias, particularly when accompanied by LQT2-like notched T waves. |
| Databáze: | OpenAIRE |
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