Intracardiac CrYoablation for AtrioVentricular Nodal Reentrant Tachycardia

Pre-Electrophysiology Study Inclusion Criteria:

- Supraventricular tachycardia (SVT) compatible with atrioventricular nodal reentrant
tachycardia (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 the
past 90 days

- Implantable cardiac rhythm device

- Atrioventricular block (first degree (PR interval ≥ 220ms), second degree, or third
degree) 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 (for example,
intracardiac mural thrombus)

- Participating in a concurrent clinical study that may confound the results of this
study

Post-Electrophysiology Study Inclusion Criteria:

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

Post-Electrophysiology Study Exclusion Criteria:

- Presence of a second inducible arrhythmia that could be confused with AVNRT during
follow-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 atrioventricular
conduction system.

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