Is the Measurement of Accessory Pathway Refractory Period Reproducible?

Abstract

IntroductionShort accessory pathway (AP) effective refractory period (ERP) is one of the risk factors in Wolff-Parkinson-White syndrome (WPW). The purpose of study was to evaluate the reproducibility of APERP measurement during a same electrophysiological study (EPS).MethodsEPS consisted of 2 APERP measurements performed prospectively in 77 patients for a WPW in control state (CS) at a cycle length of 400 ms (n=76) and after isoproterenol (n=56).ResultsIn CS, 18 patients (24 %) had the same APERP at both measurements; 41 (54.6 %) had differences from 10 to 40 ms, 17 (22.4 %) had differences > 40 ms. Among 45 patients with initial APERP > 240 ms, 7 had an APERP ≤ 240 ms at 2nd study. Among 31 patients with initial APERP ≤ 240 ms, 5 had an APERP > 240 ms at 2nd study. Pearson's product-moment correlation was 0.75. After isoproterenol, 5 patients (9 %) had the same APERPs; 37 (66 %) had differences from 10 to 40 ms and 14 had differences > 40 ms. Among 38 patients with initial APERP > 200 ms, 12 had an AP ERP ≤ 200 ms at 2nd study. Among 18 patients with initial APERP ≤ 200 ms, 10 had still APERP ≤ 200 ms at 2nd study. Pearson's product-moment correlation was 0.54.ConclusionThere are important variations of APERPs during EPS mainly after isoproterenol infusion. Therefore the values of APERPs should be interpreted cautiously.

Accuracy of the Electrocardiogram in Localizing the Accessory Pathway in Patients with Wolff-Parkinson-White Pattern

“…We observed 31 patients (27.90%) with an AP refractory period ≤ 240 ms, which has been recognized as a risk marker of sudden death in patients with WPW syndrome. 18,19 The APs evaluated in the study showed an ability to conduct the stimulus in both anterograde and retrograde directions in most individuals of both sexes (60 men [54.10%] and 39 women [35.10%]), with no significant differences between sexes (p > 0.05 ). The EPS also revealed that only eight individuals (7.20%) had an intermittent WPW pattern, with no significant differences in the type of WPW pattern by sex (p > 0.05).…”

Evolution of Clinical and Electrophysiological Data in Children with a Preexcitation Syndrome

“…In fact, in the PACES/HRS 2012 Management of Asymptomatic Preexcitation Recommendations, it was recommended that in the absence of inducible atrial fibrillation, the minimal cycle length of preexcitation should be used as an alternative . However, in our opinion the minimal cycle length of preexcitation is variable in absence of sedation mainly in children …”

Wolff–Parkinson–White syndrome: lessons learnt and lessons remaining

“…For starters, there is clear evidence that the measured accessory pathway refractory period is not consistently reproducible from one measured time to another; in fact, the reproducibility is even worse on isoproterenol. 28 Choosing a combined accessory pathway effective refractory period and minimal pre-excited cycle length during atrial incremental pacing ⩽250 ms likely increases the specificity, but may reduce the sensitivity of detecting a high-risk accessory pathway. Furthermore, the accessory pathway effective refractory period as an isolated variable is of little prognostic value for the risk of syncope, atrial fibrillation, or atrioventricular reciprocating tachycardia and is less well correlated than the SPERRI in atrial fibrillation; 9,29,30 nonetheless, the authors of these two studies showed that 5% of patients with intermittent pre-excitation may have a high-risk accessory pathway at the time of an invasive electrophysiology study, and if isoproterenol is utilised up to 11% may have pathways deemed high risk.…”

“…, 27 Although neither retrospective study was intended a priori to be an assessment of risk stratification, both groups used similar definitions of high risk: an accessory pathway effective refractory period or minimal pre-excited cycle length during incremental atrial pacing ⩽250 ms. From a purely electrophysiological standpoint, accessory pathway effective refractory period is different than a measured SPERRI or minimal pre-excited cycle length during atrial incremental pacing. For starters, there is clear evidence that the measured accessory pathway refractory period is not consistently reproducible from one measured time to another; in fact, the reproducibility is even worse on isoproterenol 28 . Choosing a combined accessory pathway effective refractory period and minimal pre-excited cycle length during atrial incremental pacing ⩽250 ms likely increases the specificity, but may reduce the sensitivity of detecting a high-risk accessory pathway.…”