Cryothermal mapping and cryoablation in the treatment of refractory cardiac arrhythmias.

Cryoablation was applied to the treatment of 15 refractory tachyarrhythmias in 12 patients, Wolff-Parkinson-White atrioventricular reentrant tachycardia (WPW) in five patients, paroxysmal atrial fibrillation (PAF) in five patients, chronic atrial fibrillation (CAF) in one patient, paroxysmal atrial tachycardia (PAT) in two patients and paroxysmal ventricular tachycardia (PVT) in two patients. At operation the accessory pathway in four patients with left-sided WPW was located by intraluminal coronary sinus and epicardial electrographic mapping techniques. Epicardial cryothermal mapping during tachycardia terminated the arrhythmias in one patient. In three patients endocardial cryothermal mapping was necessary to abolish ventriculoatrial accessory pathway conduction. In four patients with PAF and one patient with PAT the AV node/His bundle was located by both electrographic and cryothermal mapping. In one patient with concealed WPW, one with PAT, and the patient with CAF, electrographic mapping was impossible. Cryothermal mapping accurately located the AV node/His bundle in two of these patients. Electrographic mapping during PVT revealed earliest ventricular activation on the lateral left ventricular epicardium in one patient and on the right side of the intraventricular septum in the other. Cryothermal mapping at the point of earliest activation terminated both tachycardias. In all cases cryoablation was achieved by cooling to -65C for 2 minutes. In nine patients there has been no recurrence of symptomatic tachycardia during the follow-up period of 420 months but there were three partial failures when His bundle conduction resumed immediately, at 10 days, and at 2 months. The technique of electrographic mapping, cryothermal mapping and cryoablation has proved