Beat-to-beat QT dynamics in paroxysmal atrial fibrillation

Regadenoson, a Novel Pharmacologic Stress Agent for Use in Myocardial Perfusion Imaging, Does Not Have a Direct Effect on the QT Interval in Conscious Dogs

“…Regadenoson injections also caused dose-dependent shortening of the R-R and QT intervals. The maximum shortening of the R-R interval occurred earlier than the QT interval did (Figure 3, Panel A), confirming an earlier observation 14. To determine whether the regadenoson-induced shortening of the QT interval is related to an increase in HR, atrial pacing was used to mimic the increase in HR.…”

Time-Dependent Changes in QT Dynamics after Initiation and Termination of Paroxysmal Atrial Fibrillation

“…However, this was not the case; AF reduced the likelihood of developing TdP even after administration of QT prolonging drugs . AF decreased QT‐RR slope compared to SR, and bradycardia‐dependent prolongation of QT interval was attenuated during AF because QT interval gradually adapted to changes in RR interval. Therefore, AF would reduce the likelihood of developing TdP .…”

“…Assessment of QT‐RR relation is a more reliable method for rate correction of QT interval in various situations . However, only a few reports have described different characteristics of QT‐RR relation during AF in comparison with SR.…”

Comparison of QT/RR Relation Based on a 15-s Averaged ECG and a Single Beat ECG During Atrial Fibrillation

“…Larroude et al demonstrated that QT dynamics could be reliably measured in AF and were comparable with sinus rhythm when several preceding RR intervals were included in the analysis. 15 Adaptation of the QT interval to changes in the preceding RR interval consists of 2 components: the fast component (non-steady state adaptation) and the slow component (steady state adaptation). 16 In the present study, we adopted the single beat (QT/RR-single) and the 15-s averaged ECG (QT/RR-average) during AF and found that the slope of QT/RR-average was greater than that of QT/RR-single during AF and was closer to that of QT/RR during sinus rhythm.…”