Active clinical trials for "Wolff-Parkinson-White Syndrome"

A randomized pilot study to evaluate safety and efficacy endpoints for treatment of para-hisian accessory pathways according to two different strategies of lesion formation. These patients will be divided into 2 groups with different strategies of treatment: group 1 treated with radiofrequency (RF) ablation, group 2 with cryotherapy (CRYO). The primary outcome will be the recurrence rate of accessory pathway conduction after one year of follow-up. Secondary endpoints will be immediate success and rate of permanent atrioventricular (AV) block.

The study consists of the realization of a new esophageal stimulation for patients already stimulated 10 years ago. The investigators would like to make a long term evaluation of the evolution of anterograde effective refractory period of accessory duct in the WPW syndrome. This study will be realized by esophageal stimulation.

Patients complaining of tachycardia but with a negative Holter ECG, are for a limited time period offered a simplified electrophysiological(EP) examination. By a full electrophysiological study(EP study)electrodes are introduced for pacing and sensing i all four heart chambers. Where as by the mini invasive EP study only one electrode is introduced to the right atrium. The simplified procedure represent a smaller risk of complications, requires less resources but should yield the same diagnoses in more than 90% of the cases. The study is a feasibility study to see if the procedure can discover arrythmias in a fairly unselected patient population.

Prospective cohort study including 150 patients with pre-excitation on ECG referred to our clinic for risk assessment. There will be equal numbers of symptomatic and asymptomatic patients included in the study. Each patient will perform an exercise stress test on bicycle before an invasive electrophysiological test. The purpose of this study is to compare exercise stress testing on bicycle to an invasive electrophysiological study, regarding risk assessment of patients with pre-excitation. The electrophysiology study is set as reference.

Patients with preexcitation are at risk for sudden cardiac death. The pathogenesis is a rapid antegrade conduction of atrial fibrillation over the accessory pathway to the ventricle resulting in ventricular fibrillation. Today it is possible to eliminate the conduction over the accessory pathway by catheter intervention (radiofrequency ablation) with a low rate of complications and a high rate of success. In clinical practice it is therefore important to estimate the risk for sudden cardiac death in an individual patient to give an advice to the patient and the parents about the further evaluation and therapeutic strategy. The velocity of the conduction over the accessory pathway can be estimated by analysing the ECG during sinus tachycardia. If the preexcitation disappears at a relatively low heart rate, the risk for sudden death is less than in patients with persisting preexcitation at the maximal heart rate. Compared to the gold standard i.e. measurement of the refractory period of the accessory pathway during invasive electrophysiological study (EPS), the measurements at the stress ECG have been reported to be a relatively poor indicator for an elevated risk which may be explained by a high intraindividual variability of this test. This study is designed to define the clinical relevance of the stress ECG in paediatric patients with preexcitation (compared to the invasive electrophysiological study). First Hypothesis: The results of the 3 stress ECG-tests are reproducible in an individual patient. Null hypothesis: there is no difference between the three measurements of cycle length during stress ECG. Alternate hypothesis: the difference between the three measurements of cycle length is > 10%. Second Hypothesis: There is a close correlation between the results at stress ECG and the results at the invasive electrophysiological Intervention.

To correlate the antegrade effective refractory period of the accessory pathway with its anatomical location in the heart. To investigate whether the accessory pathway location can predict the high risk nature of the accessory pathway