Key result
Repeated APERP measurements show important variations that increase after isoproterenol.
Why the study?
Is the measurement of accessory pathway effective refractory period reproducible during the same electrophysiological study in patients with WPW syndrome?
Observational (n=77)
Is the measurement of accessory pathway effective refractory period reproducible during the same electrophysiological study in patients with WPW syndrome?
Accessory pathway effective refractory period measurements show significant intra-procedural variation, especially after isoproterenol, suggesting these values should be interpreted cautiously for risk stratification in WPW.
Supports cautious interpretation of accessory pathway ERP for WPW risk stratification; leaves open questions on measurement reproducibility.
INTRODUCTION: Short 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). METHODS: EPS 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). RESULTS: In 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. CONCLUSION: There are important variations of APERPs during EPS mainly after isoproterenol infusion. Therefore the values of APERPs should be interpreted cautiously.
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Oliver et al. (2012) conducted an observational in Wolff-Parkinson-White syndrome (n=77). Repeated accessory pathway effective refractory period (APERP) measurements was evaluated on Reproducibility of APERP measurement (Pearson's correlation 0.75 in control state, 0.54 after isoproterenol). Repeated measurements of accessory pathway effective refractory period showed important variations, with a Pearson's correlation of 0.75 in the control state and 0.54 after isoproterenol.
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