Tipik Atriyal Flutterda Kavotriküspit İstmus Ablasyonu Sonrası Unipolar Voltaj Azalmasının CTI Blok Süresi ile İlişkisi

Öz

Amaç: Kavotriküspit istmus (CTI) ablasyonu, tipik atriyal flutter tedavisinde yerleşik bir yöntem olup, işlemin sonlanım noktası çift yönlü CTI blok elde edilmesidir. Bununla birlikte, lezyon kalitesini yansıtan ve iletim  gecikmesini öngören güvenilir intraprocedürel belirteçler sınırlıdır. Bu çalışmada, radyofrekans ablasyon sonrası unipolar voltaj azalması ile CTI blok süresi uzaması arasındaki ilişkinin değerlendirilmesi amaçlandı. 

Gereç ve Yöntemler: Bu tek merkezli retrospektif çalışmaya, tipik atriyal flutter nedeniyle radyofrekans CTI ablasyonu uygulanan 51 hasta dahil edildi. Ablasyon öncesi ve sonrası unipolar voltaj oranı, bipolar voltaj azalması ve empedans düşüşü analiz edildi. Birincil sonlanım noktası, CTI blok süresi oranının >2 olması ile tanımlanan anlamlı CTI blok süresi uzamasıydı. Korelasyon, çok değişkenli regresyon ve ROC analizleri gerçekleştirildi.
Bulgular: Unipolar voltaj azalması ile CTI blok süresi oranı arasında anlamlı pozitif korelasyon saptandı (r=0,531, p<0,001). Buna karşılık, bipolar voltaj azalması ile CTI blok süresi arasında anlamlı ilişki bulunmadı (p>0,05). Çok değişkenli analizde, unipolar voltaj azalması CTI blok süresi uzamasının bağımsız bir belirleyicisi olarak saptandı (β=0,583, p<0,001). ROC analizinde, unipolar voltaj azalmasının anlamlı CTI blok süresi artışını öngörmede mükemmel ayırt edici güce sahip olduğu gösterildi (eğri altında kalan alan=0,97, %95 güven aralığı: 0,92-1,00). En uygun kesim değeri ≥%61,7 olup, duyarlılık %91,3 ve özgüllük %100 olarak bulundu.
Sonuç: Unipolar voltaj azalması, CTI blok süresi uzamasının güçlü ve bağımsız bir belirleyicisidir ve CTI ablasyonu sırasında lezyon kalitesini değerlendirmede güvenilir bir intraprocedürel belirteç olarak kullanılabilir. Unipolar voltaj değerlendirmesinin rutin uygulamaya dahil edilmesi, işlem etkinliğini artırabilir ve ablasyon sonuçlarını optimize edebilir.
 

Anahtar Kelimeler

• Kavotriküspit İstmus Ablasyonu
• Tipik Atriyal Flutter
• Unipolar Voltaj
• Radyofrekans Ablasyonu
• CTI Blok Süresi
• Elektroanatomik Haritalama

Destekleyen Kurum

Bu çalışma için herhangi bir finansal destek alınmamıştır.

Etik Beyan

The study protocol was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the local institutional ethics committee (Ankara Etlik City Hospital (decision no: 2026-038, date: 27.01.2026)).

RELATIONSHIP BETWEEN UNIPOLAR VOLTAGE REDUCTION AND CTI BLOCK TIME AFTER CAVOTRICUSPID ISTHMUS ABLATION IN TYPICAL ATRIAL FLUTTER

Öz

Objective: Cavotricuspid isthmus (CTI) ablation is an established treatment for typical atrial flutter, with the 
procedural endpoint being the achievement of bidirectional CTI block. However, reliable intraprocedural markers reflecting lesion quality and predicting conduction delay are limited. This study aimed to evaluate the relationship between unipolar voltage reduction after radiofrequency ablation and prolongation of CTI block time.
Material and Methods: In this single-center retrospective study, 51 patients who underwent radiofrequency CTI ablation for typical atrial flutter were included. Pre- and post-ablation unipolar voltage ratio, bipolar voltage reduction, and impedance drop were analyzed. The primary endpoint was defined as significant CTI block time prolongation, expressed as a CTI block time ratio >2. Correlation, multivariable regression, and ROC analyses were performed.
Results: A significant positive correlation was observed between unipolar voltage reduction and CTI block time ratio (r=0.531, p<0.001). In contrast, no significant association was found between bipolar voltage reduction and CTI block time (p>0.05). In multivariable analysis, unipolar voltage reduction was identified as an independent predictor of CTI block time prolongation (β=0.583, p<0.001). ROC analysis demonstrated excellent discriminative ability of unipolar voltage reduction in predicting significant CTI block time prolongation (area under the curve=0.97, 95% confidence interval: 0.92-1.00). The optimal cutoff value was ≥61.7%, with a sensitivity of 91.3% and specificity of 100%.
Conclusion: Unipolar voltage reduction is a strong and independent predictor of CTI block time prolongation and may serve as a reliable intraprocedural marker for assessing lesion quality during CTI ablation. Incorporating unipolar voltage assessment into routine practice may enhance procedural efficacy and optimize ablation outcomes.

Anahtar Kelimeler

• Cavotricuspid Isthmus Ablation
• Typical Atrial Flutter
• Unipolar Voltage
• Radiofrequency Ablation
• CTI Block Time
• Electroanatomical Mapping

Destekleyen Kurum

The authors received no financial support for this study.

Etik Beyan

The study protocol was conducted in accordance with the principles of the Declaration of Helsinki and was approved by the local institutional ethics committee (Ankara Etlik City Hospital (decision no: 2026-038, date: 27.01.2026)).

Kaynakça

1. Brugada J, Katritsis DG, Arbelo E, Arribas F, Bax JJ, Blomstrom-Lundqvist C, et al. ESC guidelines for the management of patients with supraventricular tachycardia. Eur Heart J. 2020;41(5):655-720.
2. Sahlool Y, Dacquay Y, Avedikian S, Kim JHJ, Sovari Optimal local impedance parameters for catheter ablation of the cavotricuspid isthmus in atrial flutter patients: a retrospective analysis. HCA Healthc J Med. 2025;6(5):519-25.
3. Ducceschi V, Zingarini G, Nigro G, Brasca FMA, Malacrida M, Carbone A, et al. Optimized radiofrequency lesions through local impedance guidance for effective CTI ablation in right atrial flutter. Pacing Clin Electrophysiol. 2022;45(5):612-8.
4. Johner N, Namdar M, Shah DC. Typical atrial flutter: a practical review. J Cardiovasc Electrophysiol. 2025;36(10):2677-91.
5. Sasaki T, Nakamura K, Minami K, Take Y, Nakatani Y, Miki Y, et al. Local impedance measurements during contact force-guided cavotricuspid isthmus ablation for predicting effective radiofrequency ablation. J Arrhythm. 2022;38(2):245-52.
6. Schlageter V, Badertscher P, Luca A, Krisai P, Spies F, Kueffer T, et al. A single-beat algorithm to discriminate far-field from near-field bipolar voltage electrograms from the pulmonary veins. J Interv Card Electrophysiol. 2023;66(8):2047-54.
7. Perge P, Petrovic N, Sallo Z, Piros K, Nagy VK, Abraham P, et al. Early rapid local impedance drop is associated with acute lesion efficacy during pulmonary vein isolation. Europace. 2024;26:euae260.
8. Sun Y, Wang B, Feng M, Yu Y, Gao F, Zhuo W, et al. Ablation index value for transmural lesions based on unipolar electrograms in patients with paroxysmal atrial fibrillation undergoing pulmonary vein isolation. Front Cardiovasc Med. 2024;11:1449623.

9. Paymard M, Deyell MW, Laksman ZW, Yeung-Lai-Wah JA, Chakrabarti S. Correlation of unipolar electrogram modification with ablation index during pulmonary vein isolation: a pilot study. Pacing Clin Electrophysiol. 2023;46(2):138-43.
10. Yavin HD, Younis A, Derakhshan A, Koch Z, Krywanczyk A, Bryce H, et al. Feasibility of unipolar signal-guided ablation in creating contiguous lines of conduction block: a proof-of-concept study. Heart Rhythm. 2025;22(9):2938-47.
11. Tzeis S, Gerstenfeld EP, Kalman J, Saad EB, Sepehri Shamloo A, Andrade JG, et al. 2024 European Heart Rhythm Association/Heart Rhythm Society/Asia Pacific Heart Rhythm Society/Latin American Heart Rhythm Society expert consensus statement on catheter and surgical ablation of atrial fibrillation. Europace. 2024 ;21(9):e31-e149.
12. Sabzwari SRA, Rosenberg MA, Mann J, Cerbin L, Barrett C, Garg L, et al. Limitations of unipolar signals in guiding successful outflow tract premature ventricular contraction ablation. JACC Clin Electrophysiol. 2022;8(7):843-53.
13. Tomlinson DR, Myles M, Stevens KN, Streeter AJ. Transmural unipolar electrogram change occurs within 7 seconds at the left atrial posterior wall during pulmonary vein isolation. Pacing Clin Electrophysiol. 2019;42(7):922-9.