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

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Abstract
Cryoablation was applied to the treatment of 15 refractory tachyarrhythmias in 12 patients, Wolff-Parkinson-White atrioventricular reentrant tachycardia (WPW) in 5 patients, paroxysmal atrial fibrillation (PAF) in 5 patients, chronic atrial fibrillation (CAF) in 1 patient, paroxysmal atrial tachycardia (PAT) in 2 patients and paroxysmal ventricular tachycardia (PVT) in 2 patients. At operation the accessory pathway in 4 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 1 patient. In 3 patients endocardial cryothermal mapping was necessary to abolish ventriculoatrial accessory pathway conduction. In 4 patients with PAF and 1 patient with PAT, the atrioventricular node/His bundle was located by electrographic and cryothermal mapping. In 1 patient with concealed WPW, 1 with PAT and the patient with CAF, electrographic mapping was impossible. Cryothermal mapping accurately located the AV node/His bundle in 2 of these patients. Electrographic mapping during PVT revealed earliest ventricular activation on the lateral left ventricular epicardium in 1 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 -65.degree. C for 2 min. In 9 patients there was no recurrence of symptomatic tachycardia during the follow-up period of 4-20 mo., but there were 3 partial failures when His bundle conduction resumed immediately, at 10 days, and at 2 mo. The technique of electrographic mapping, cryothermal mapping and cryoablation proved to be simple and successful.