Electrophysiological features and possibilities of ablation of ectopic atrial tachycardia from the area of the non-coronary cusp of the aortic valve

Background. Ectopic atrial tachycardia near the bundle of His can come from the non-coronary cusp of the aortic valve and is very rare. The experience of successful use of catheter ablation with this type of tachycardia is described in a limited number of patients. Objective. To study the electrophysiological characteristics and features of the mapping of ectopic atrial tachycardia from the region of the non-coronary sinuses of Valsalva, to demonstrate the long-term effectiveness and safety of arrhythmia elimination using radiofrequency ablation. Material and methods. The study included 6 patients (mean age 41.4±17.3 years; 4 females) with symp-tomatic, refractory to antiarrhythmic therapy atrial tachycardia. Activation mapping of the right and left atria was performed during tachycardia to determine the zone of the earliest activation. As a result, the earliest atrial activation was identified in the His bundle region in all patients 46.7±8.4 and 44.2±7.3 ms ahead of the reference electrode on the right and left, respectively. However, radiofrequency ablation in these areas of the right and left atriums led only to temporary relief of tachycardia or was ineffective. The non-coronary cusp of the aortic valve was mapped by retrograde transaortic access through the right femoral artery. Results. Mapping the non-coronary cusp of aortic valve showed that activation at this location was the earliest, ahead of the entry with reference electrodes for 67.3±7.6 (from 58 to 71) ms and the beginning of P-wave 28.5±16.2 (within 25–42) ms. Atrial activation in the non-coronary sinuses of Valsalva occurred earlier than activation in the right and left atriums in all patients by an average of 11.4±3.5 (range 8 to 18) ms. P-wave morphology was biphasic in lead II, III and aVF (4 patients), positive in lead aVL (5 patients). The morphology of P-waves in lead I was predominantly positive or isoelectric (in 4 of 6 patients). In all cases, thoracic leads showed two-phase negative-positive deviation in V1 and V2 leads and positive deviation in V6. In addition, the analysis of morphological features of the electrogram recorded during tachycardia at the site of effective ablation revealed the ratio of atrial and ventricular electrograms more than 1 in all patients. In all patients tachycardia was successfully stopped by ablation in the zone of the earliest activation within the non-coronary sinus of Valsalva (maximum power 35 W, maximum temperature 45 °C) for 4.5±2.1 (2–8) s without complications. During the follow-up period of 10.4±3.8 months, all patients were free of arrhythmia without antiarrhythmic drugs. Conclusion. The area of earliest activation in the non-coronary cusp of the aortic valve can be identified by careful activation mapping. Radiofrequency ablation in this region is a safe and effective method of eliminat-ing ectopic atrial tachycardia in the case of paragisial localizations, with good long-term results. In addition to the morphological features of the P-wave, the atrial and ventricular ratio of local electrograms during tachycardia facilitated the localization of the successful site.