Cryoablation is a technique used in cardiac electrophysiology in which extremely cold temperatures are applied to heart tissue to destroy it or create a precisely controlled scar. During catheter ablation procedures, cryoablation eliminates abnormal electrical circuits or triggers that cause arrhythmias by freezing the target tissue to temperatures below -40 to -70°C, disrupting cell structures and triggering cell death.
Cryoablation has a particular advantage in cardiac electrophysiology: before permanently destroying tissue, it can be used in a reversible ‘cryomapping’ phase at moderately cold temperatures (around -30°C). At this temperature the tissue is temporarily blocked but not permanently damaged. This allows the electrophysiologist to test whether ablating a particular area will be effective and safe before committing to a permanent lesion, reducing the risk of inadvertent damage to adjacent structures such as the AV node.
In the UK, cryoablation is commonly used for ablation of atrioventricular nodal re-entrant tachycardia (AVNRT) and for pulmonary vein isolation in atrial fibrillation using a cryoballoon catheter. The cryoballoon is inflated to occlude the pulmonary vein opening and delivers circumferential freezing to create an isolation lesion around it. Cryoablation is an alternative to radiofrequency (heat-based) ablation; the choice between them depends on the arrhythmia, anatomy, and operator experience.
Cryoablation is generally well tolerated. Potential complications are similar to other ablation procedures and include vascular access complications, phrenic nerve injury (due to proximity of the phrenic nerve to the pulmonary veins during cryoballoon ablation), and, rarely, pulmonary vein stenosis.
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