ASSESSMENT OF EFFECTIVENESS OF ABLATION OF VENTRICULAR TACHYARRHYTHMIA ORIGINATING FROM THE RIGHT VENTRICULAR INFLOW TRACT IN PATIENTS WITHOUT UNDERLYING HEART DISEASE

To assess effectiveness and safety of radiofrequency ablation (RFA) of ventricular tachyarrhythmia (VTA) located in the right ventricular inflow tract, 32 patients aged 39.7±19.1 years were examined and treated. The number of ventricular premature contractions (PVC) detected was 17,642±13,475; sustained ventricular tachycardia (VT) was documented in 7 patients (21.9%); implantable cardioverters-defibrillators (ICD) were implanted in 4 patients (12.5%). Antiarrhythmic therapy was ineffective in all patients. RFA was performed using the NaviStar ThermoCool irrigated electrode, with the irrigation velocity of 17 ml/min, maximal power or 40 W, maximal temperature of 43°C, and the duration of each application of 40 60 s. Freedom of VPC/VT throughout the follow-up period after single or repetitive ablations was the study primary endpoint. The secondary study endpoints were as follows: complications of the procedure and the number of VPC. In 20 patients (62.5%), VTA originated from the tricuspid valve area and, in 12 patients (37.5%), from the basal part of the right ventricle. In 29 patients (90.6%), the only morphology of PVC/VT was revealed; 3 patients (9.4%) had polymorphous PVCs. The number of points for 3D reconstruction of the right ventricular inflow tract endocardial surface was 37±11. The normal endocardial voltage in the right ventricular inflow tract was revealed in all patients. The number of radiofrequency applications was 10.6±3.2, with the fluoroscopy exposure of 6.6±2.8 min and the procedure duration of 59.7±10.2 min. In 2 patients (6.2%), RFA was not performed because of parahisian location of PVs and a high risk of development of complete atrio-ventricular block. In one patient (3.1%) with the PVC/VT location in the free wall, the RFA in the right ventricle was ineffective. Thus, the overall effectiveness of RFA was 93.8% (30 patients). The late effectiveness of the procedure after the single ablation was 87.5%, after repetitive procedures, 93.8%. Thus, RFA of VTA originating from the right ventricular inflow tract is a highly effective and safe technique of treatment which permits one to maintain the sinus rhythm during the entire follow-up period.

ventricular premature contractions, ventricular tachycardia, electro-anatomic mapping, radiofrequency catheter ablation, antiarrhythmic therapy, electrocardiogram, Holter monitoring

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