| 1. BackgroudSlow pathway RF ablation is a first-line therapy for the treatment of atrioventricular nodal reentrant tachycardia (AVNRT). The procedure is highly effective; however, unintentional AV block occurs in 0.4- 1.2% .While the risk of AV block is low, it remains troublesome considering the benignity of the arrhythmia. In some cases, an anomalous anatomy of Koch's triangle with a posterior dislocation of the AV node and/or fast pathway may be a challenge for RF ablation. Consequently, the use of cryo energy may be useful in such cases.The duct of In particular, it allows for the possibility ofpredicting - through its cryomapping feature - the acute effect of the lesion before it is created. This is due to the ability of producing a transient electrical effect in the target tissue before performing the cryoablation. Cryoablation is an effective safe therapy for AVNRT in multi-cental Rudimentary clinical study.2. PurposeTO investgate the characteristic of Cryoadhesion in transcatheter cryoablation of atrioventricular nodal reentrant tachycardia (AVNRT), review the temperature, fluence and pressure of liquid dinitrogen monoxide when the ablation electrodes adhere the target.3. Methods18 cases underwent tanscather cryoablation of AVNRT . The slow pathway was targeted in every patient. Cryomapping was used to search an effective target site by cooling down the distal ablation electrode to -30℃ . Then cryoablation was performed by freezing the ablation electrode to -75℃. Start fluoroscope when the temperature of distal ablationelectrode reduces to 0℃, the catheter sticks to the target when you see the distal ablation electrode play a"head-noding"movement, record the temperature, fluence and pressure of liquid dinitrogen monoxide that moment.4. resultThe maximum adhereing temperature is —16.2±1.8 ℃,the lowest adhereing temperature is -21.4±1.8 ℃,Mean temperature is -18.5±1.6℃.it takes 22.2 ± 4.8 seconds for the cather sticks to the tissue.the mean Fluence of liquid dinitrogen monoxide (N2O) is 14.9±1.1 ML/Min, mean pressure is 678.6 ± 23.8 Pa/Square Inch.There was no migration of the joint between the target point and the distal ablation electrode ,During cromapping and cryoablation.5. conclusionCryoablation is an effective therapy for AVNRT, croadhesion raise the security of this therapy. |
