Relationship between age and anterograde refractoriness of the accessory pathway in Wolff-Parkinson-White patients.

In 22 patients (age range 13-40 years) with Wolff-Parkinson-White ECG pattern without evidence of associated cardiomyopathy we measured the anterograde effective refractory period of the accessory pathway (ERP-AP) by extrastimulus method (at twice diastolic threshold) during atrial pacing (100/min). The ERP-AP range was 220-480 ms. There was a significant direct correlation between age and ERP-AP (r = 0.50, p less than 0.01). An ERP-AP less than or equal to 250 ms was found in 4 patients (age less than or equal to 23 years). This is noteworthy in the light of reports that, over the years: (1) typical Wolff-Parkinson-White ECG signs can disappear and (2) the frequency of tachycardic episodes decreases. Our data suggest a lower risk of high ventricular rates during atrial fibrillation with increasing age.