The Wolff--Parkinson--White syndrome may be associated with life-threatening or disabling tachyarrhythmia, owing to the presence of an atrioventricular accessory pathway (Kent bundle). The first division of a Kent bundle was reported in 1969, but this surgery is still confined to a few centres. Between September 1981 and October 1982, 19 patients (13 men, 6 women) aged 16 to 46 years (mean 25 years) with the Wolff--Parkinson--White syndrome associated with refractory arrhythmia underwent surgery. Kent bundles were localized in the electrophysiology laboratory and by intraoperative cardiac mapping. The 19 patients had a total of 22 distinct Kent bundles. The bundles were divided using open-heart (13 patients) or closed-heart (6 patients) technique. All Kent bundles were confirmed as nonfunctioning before discharge. A delta wave recurred in two patients. The Kent bundle was not functional in one patient. The other is controlled by a drug that was previously ineffective. There were no complications or deaths. Kent bundles can be divided with minimal morbidity and a high success rate (more than 90%). Surgery is indicated in patients with refractory arrhythmias or in young patients who would be required to take medication for life.