Cryoablation of the Retrograde Fast Pathway as Treatment for AVNRT
Cryoablation of the Retrograde Fast Pathway as Treatment for AVNRT
In this study a new technique for ablation in atrioventricular nodal reentrant tachycardia
 using cryo-energy will be studied in cases where the standard approach has higher risk.
Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common cause of fast
 heartbeats in young people. People with AVNRT have two pathways within the heart, the fast
 pathway (FP) and slow pathway (SP). A treatment for AVNRT is ablation (burning or freezing)
 of the SP. This can be done with either radiofrequency or cryo-energy. A complication which
 occurs in 1% of cases is AV block (AVB), meaning the person needs a pacemaker.

 Slow pathway ablation is a problem in people when the electrocardiogram (ECG) shows a long PR
 interval, with greater rates of AVB. This accounts for 5% of AVNRT cases. A possible solution
 is to treat the FP with cryo-energy and leave the SP intact. This pilot study aims to show
 this is safe and effective.
Inclusion Criteria:

 -  Documented supraventricular tachycardia (SVT)

 -  Planned to undergo electrophysiology (EP) study and ablation

 -  PR interval on ECG <220ms (Group 1) or >220ms (Group 2)

 Exclusion Criteria:

 -  Pregnancy

 -  Age <18 years

 -  Inability to provide consent

 -  High likelihood of tachycardia mechanism other than AVNRT (e.g. Pre-excitation on
 surface ECG, atrial tachycardia)