Intracardiac CrYoablation for AtrioVentricular Nodal Reentrant Tachycardia

Pre-Electrophysiology Study Inclusion Criteria:

• Supraventricular tachycardia (SVT) compatible with atrioventricular nodal reentranttachycardia (AVNRT), documented by ECG, TTM, Holter or event monitor

Pre-Electrophysiology Study Exclusion Criteria:

• History of sustained (≥30 seconds) of ventricular tachycardia

• Atrial tachycardia or other arrhythmia that could be confused with AVNRT

• Reversible cause of SVT

• History of previous AVNRT ablation

• Therapy with amiodarone within last 90 days

• Unstable angina/myocardial infarction/open heart surgery in past 60 days

• New York Heart Association (NYHA) Classification III or IV currently or within thepast 90 days

• Implantable cardiac rhythm device

• Atrioventricular block (first degree (PR interval ≥ 220ms), second degree, or thirddegree) or left bundle branch block

• Stroke or transient ischemic attack within the past 180 days

• Life expectancy less than 12 months

• Female known to be pregnant

• Unable/unwilling to give informed consent

• Unable/unwilling to comply with follow-up visits and study requirements

• Less than 18 years of age

• Active systemic infection

• Cryoglobulinemia

• Other conditions where the manipulation of the catheter would be unsafe (forexample, intracardiac mural thrombus)

• Participating in a concurrent clinical study that may confound the results of thisstudy

Post-Electrophysiology Study Inclusion Criteria:

• Subject must have one electrophysiology study documented inducible sustained (greater than or equal to 15 seconds) supraventricular tachycardia that isclassified as AVNRT.

Post-Electrophysiology Study Exclusion Criteria:

• Presence of a second inducible arrhythmia that could be confused with AVNRT duringfollow-up or will likely result in ablation within the next 6 months

• Presence of inducible sustained ventricular tachycardia or fibrillation

• Presence of an accessory pathway

• Presence of abnormal conduction or refractoriness parameters of the atrioventricularconduction system.

• Indication for a pacemaker, defibrillator or cardiac resynchronization therapy (CRT)