Journal of cardiovascular electrophysiology
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J. Cardiovasc. Electrophysiol. · Jun 2007
Clinical TrialA rate-independent method of assessing QT-RR slope following conversion of atrial fibrillation.
Following conversion of atrial fibrillation (AF), QT interval transiently and variably prolongs and can trigger torsades de pointes (TdP). However, quantitative analysis of risk in this setting is difficult because cycle length variability during AF makes rate-corrected QT impossible to calculate. In this study, a newly developed method to study heart rate dependence of the QT interval during AF was applied to assess the QT-RR relationships prior to and following cardioversion in patients with AF. ⋯ The results of this study demonstrate that QT interval can be reliably measured in AF using a method that is independent of heart rate. We also showed that cardioversion of AF acutely increases the QT interval and the steepness of the QT-RR slope.