Intracardiac Echocardiography Guided Slow Pathway Cryoablation

Atrioventricular nodal reentry tachycardia is best treated with catheter ablation aimed at disruption of conduction of the slow pathway. There are currently two possible options for this ablation: radiofrequency ablation and cryoablation. The first seems to result in superior success rate, however carries a small risk of collateral damage of the heart conduction system, specifically the atrioventricular (AV) node. Cryoablation seems less effective, but safer as AV nodal damage can be avoided. The aim of this study is to prospectively test possible improved efficcacy of cryoablation of the slow pathway with the use intraprocedural intracardiac echocardiography.

Inclusion Criteria:ECG or holter ECG evidence of regular narrow QRS complex tachycardia, intraprocedural pacing maneuvers in sinus rhythm and during ongoing tachycardia indicating presence of AVNRTExclusion Criteria:terminal or severe medical condition with expected survival of less then 12 months, deep venous thrombosis preventing access to the femoral vein, intracardiac thrombi, anatomical irregularities of pelvic veins and/or inferior vena cava, inability to induce AVNRT after the initial induction and diagnosis - enables exclusion of procedures where accidental mechanical termination of slow pathway conduction with the cryoablation catheter occurs