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There is less certainty about the recommendations for radio-frequency ablation as a therapeutic option for Wolff-Parkinson-White syndrome in children as opposed to adults because of the different natural history and the age-related risks of ablation. To help decision-making, we evaluated the long term clinical evolution and electrophysiologic characteristics of pre-excitation in our series of children and young adults. We reviewed the clinical course of 109 patients below the age of 18 years who had been followed up over a period of 9+4 years, with a range from one to 27 years. This corresponded to 986 patient-years. We examined also the electrophysiologic data from 98 of those patients who underwent a transesophageal study. At the discovery of pre-excitation, 59% of patients were asymptomatic, while 29% developed supraventricular tachycardia during follow-up. The peak incidence of the onset of supraventricular tachycardia occurred during infancy. These patients had the highest incidence of subsequent spontaneous disappearance of the tachycardia (53%), such a favourable evolution being encountered in only 12% of patients in whom the abnormal rhythm first appeared after 12 years of age. Chronic medical treatment was required in 47% of patients, and proved completely effective in 45% of cases. The potential to induce atrial fibrillation, and the incidence pre-excitation considered to be high risk, with the shortest pre-excited RR interval equal to or less than 220 msec, was lowest in the group of patients aged less than 6 years of age, and highest in those older than 12 years of age (p <0.001). Pathways producing arrhythmia with high risk were more common in symptomatic (29%) than in asymptomatic patients (7%) (p<0.001). No mortality occurred. On the basis of our findings, we suggest that ablation should be avoided before the age of 5 or 6 years. Thereafter, the procedure should become the first line of treatment for symptomatic patients older than 12 years of age.

Thrombosis Cosmi B, Legnani C, Cini M. Thromb Res 2008;122:610-7.Conclusion: Elevated levels of D-dimer and factor VIII at 30 Ϯ 10 days after cessation of vitamin K antagonist (VKA) therapy for a first episode of idiopathic proximal deep venous thrombosis (DVT) are independent risk factors for recurrent venous thromboembolism (VTE).Summary: The optimal duration of VKA therapy after a first episode of VTE is unknown. It appears VKA extension after unprovoked VTE can reduce the risk of recurrent VTE but at the potential price of increased bleeding. There is therefore intense interest in stratifying patients with idiopathic VTE with respect to risk factors that may increase rates of recurrence. The specific objective of this study was to assess the risk of recurrence of VTE associated with elevated D-dimer levels and factor VIII levels after withdrawal of VKA therapy for symptomatic idiopathic proximal VTE.Consecutive outpatients with the first episode of idiopathic proximal DVT were enrolled into the study after cessation of VKA therapy. At 30 Ϯ 10 days after cessation of VKA therapy, levels of D-dimer (cutoff value, 500 ng/mL) and chromogenic factor VIII, as well as inherited thrombophilias were determined. Follow-up extended for 2 years.Overall recurrence rate of VTE was 16.4% (55 of 336; 95% confidence interval [CI], 13%-21%). The multivariate hazard ratio for recurrence was 2.45 (95% CI, 1.24-4.99) for abnormal D-dimer and 2.76 (95% CI, 1.57-4.85) for factor VIII Ͼ75th percentile (2.42 /mL). The values were adjusted for age, sex, and thrombophilia. Compared with normal levels of D-dimer and factor VIII, the multivariate hazard ratio was 4.5 (95% CI, 1.7-12.2) for normal D-dimer levels with factor VIII Ͼ2.42 U/mL, and 2.7 (95% CI, 1.2-6.6) and 7.1 (95% CI, 2.8-17.6) for abnormal D-dimer with factor VIII, respectively, below and above 2.42 U/mL. Comment: The appropriate length of treatment with VKA therapy for patients with idiopathic VTE is unknown. The data suggest the longer the treatment period with VKA, the less the recurrence rates of VTE. Of course, VKAs are associated with increased risk of bleeding and are inconvenient for the patient. There is therefore intense interest in stratifying risk among those patients with idiopathic VTE. This is another study that attempts to do just that. The percentage of patients with both normal D-dimer and factor VIII Ͻ75th percentile was 37%. This implies that at least a third of patients with idiopathic VTE have a low risk of VTE recurrence. Larger studies are warranted to determine if the combination of factor VIII and D-dimer analysis can be used to tailor duration of VKA therapy after idiopathic VTE.