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Prognostic value of time dependent voltage abatement during remote magnetic navigation guided ablation in idiopathic right ventricular outflow tract arrhythmias Purpose: We set out to evaluate if time related voltage abatement (dV/dt) of ventricular electrograms (EGM) during catheter ablation of idiopathic right ventricular outflow tract (RVOT) arrhythmias using the Stereotaxis Niobe II system is an efficient marker of long-term procedural success.Methods: Twenty-six consecutive patients with acute success of RVOT ablation for premature ventricular contractions (PVCs) and/ or ventricular tachycardia (VT) suggestive of RVOT origin were included. Late success was defined as freedom of ventricular ectopies originating from the RVOT after 3 months of follow up without antiarrhythmic drugs (AAD).Results: After 3 months follow-up 20 of 26 patients (77%) remained free of symptoms and arrhythmias (group 1) and recurrences occurred in 6 patients (23%) (group 2). 'Warming up' during RF applications occurred respectively in 85% and 83,33 % of patients (p=0,46), after a mean period (dt 2) of 4,72 ± 9,42 vs 10,75 ± 11,34 sec (p=0,045). The time intervals from the onset of RF delivery (t0) to significant voltage abatement (>90%) or reversal of EGM polarity (t1) between the two groups were: 9,11 ± 5,11 vs 32,16 ± 10,33 (p=0,00006). dV/dt1 was 95,44 ± 87,6 vs 23,5 ± 16,97μV/s (P=0,024). Conclusion:Time related voltage abatement of ventricular EGM together with time interval from onset of RF ablation to significant voltage abatement (>90%) or reversal of EGM polarity and time interval from RF delivery to onset 'warming up' are possible predictors of long term success after RF ablation of idiopathic RVOT arrhythmias.

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Naším cílem bylo zjistit, zda časově závislé snížení voltáže (dV/dt) na komorových elektrogramech (EGM) během katetrizační ablace idiopatických arytmií z výtokového traktu pravé komory (right ventricular outfl ow tract, RVOT) s použitím systému Stereotaxis Niobe II představuje účinný ukazatel dlouhodobé úspěšnosti výkonu. Metody: Do studie bylo zařazeno 26 po sobě následujících pacientů s akutní úspěšnou ablací RVOT pro předčasné komorové stahy (premature ventricular contractions, PVC) a/nebo komorové tachykardie (KT) s původem nejspíše v RVOT. Pozdní úspěšnost byla defi nována jako vymizení komorových ektopií z RVOT po tříměsíčním sledování bez antiarytmik (antiarrhythmic drug, AAD). Výsledky: Po tříměsíčním sledování vymizely symptomy i arytmie u 20 (skupina 1) z 26 pacientů (77 %), přičemž k recidivě došlo u šesti pacientů (23 %) (skupina 2). Během RF ablace byl "warming up" fenomén pozorován u 85 %, resp. 83,33 % pacientů (p = 0,46) po průměrné době (dt 2) 4,72 ± 9,42, resp. 10,75 ± 11,34 s (p = 0,045). Doba od zahájení aplikace RF energie (t0) do významného snížení voltáže (> 90 %) nebo obrácení polarity EGM (t1) u obou skupin činila 9,11 ± 5,11, resp. 32,16 ± 10,33 (p = 0,00006). Hodnota dV/ dt1 byla 95,44 ± 87,6, resp. 23,5 ± 16,97 μV/s (p = 0,024). Závěr: Časově závislé snížení voltáže na komorovém EGM spolu s dobou od zahájení RF ablace do významného snížení voltáže (> 90 %) nebo obrácení polarity EGM a dobou od aplikace RF energie do vzniku "warming up" fenoménu představují možné prediktory dlouhodobé úspěšnosti RF ablace idiopatických arytmií vycházejících z RVOT.

Introduction The majority of idiopathic ventricular arrythmias arise from the right ventricular outflow tract (RVOT) and they represent nearly 10% of all ventricular tachycardia (VT) admissions. It is paramount to precisely predict the origin of RVOT arrhythmias to define the appropriate approach before the ablation procedure. Conventional 12-lead electrocardiogram (ECG) is a useful tool for analysing cardiac arrhythmias, and numerous ECG algorithms for predicting the origin of RVOT arrhythmias have been reported. Purpose To compare the predictive accuracy of five different algorithms as verified by successful ablation site using 3D electroanatomical non-contact mapping in patients with symptomatic and asymptomatic but high ventricular burden right ventricular outflow tract (RVOT) tachycardias. Methods 28 consecutive patients admitted for radiofrequency catheter ablation for symptomatic and asymptomatic, but high ventricular burden idiopathic premature ventricular contractions (PVC) were recruited for this study. All patients had previous failed or intolerant to beta-blocker and/or at least one class IC anti-arrhythmic agents, and they had normal left ventricular ejection fraction. All patients had documented monomorphic PVC with left bundle branch block morphology and an inferior axis. Concordance of the arrhythmia origin based on ECG algorithm and 3D mapping system site were further evaluated. Of the five algorithms, two algorithms with easy-applicability and having a memorable design (Dixit and Joshi) and three algorithms with more complex and detailed design (Ito, Zhang, Pytkowski) were selected for comparisons. Results Assessment of the diagnostic accuracy showed that each of the five algorithms had only moderate accuracy, and the greatest accuracy was observed in the algorithm proposed by Pytkowski algorithm when assessed by a general cardiologist and Dixit and Pytkowski algorithms when evaluated by the electrophysiologist. However, when the algorithms were compared for their accuracy, specificity, sensitivity, no significant differences were found (p=0.99). Conclusions All the five published 12-lead ECG algorithms for RVOT location were similar in terms of the diagnostic accuracy, specificity, and sensitivity. In our study, Pytkowski algorithm exhibits the best accuracy and sensitivity among the algorithms, while predicting a precise location and when evaluation is performed by electrophysiologists and/or cardiologists. Funding Acknowledgement Type of funding sources: None.