Risk Factors for Atrial Fibrillation Recurrence in Patients Undergoing Ablation

Ercan ÇEĞİLLİ; Aykut DEMİRKIRAN; Serhat ÇALIŞKAN; Ferit BÖYÜK; Ali AYDINLAR

doi:10.4274/nkmj.galenos.2021.29290

ABSTRACT

Aim:

The current study aimed to investigate the predictors of recurrence in patients with paroxysmal atrial fibrillation (AF) undergoing cryoballoon ablation.

Materials and Methods:

This study was conducted with the participation of the patients who underwent cryoballoon ablation between October 2013 and March 2016. Patients’ medical records were retrospectively evaluated. Patients were divided into two groups as those with AF recurrence and those without AF recurrence.

Results:

A total of 68 patients undergoing cryoballoon ablation were included in the study. The mean age of the patients was 57.3±12 years, and 32% were male. Concomitant conditions included coronary artery disease in 25 patients (36.8%), diabetes mellitus in 9 (13.2%), hypertension in 46 (67.6%), and history of cerebrovascular event in 3 (4.4%). During the early period involving the initial three months, AF recurrence was found in 16 patients (23.5%), while 52 (76.5%) remained in the sinus rhythm during the follow-up. There were significant differences between two groups in left atrium size (38±5.3 and 44±6.6, p=0.003), left atrial appendage (LAA) flow rate [38 (24-62) cm/sec and 28 (22-55) cm/sec, p=0.001], presence of pulmonary venous anomaly [5 (9.6%) and 6 (37.5%), p=0.016], the number of antiarrhythmic drugs before the ablation (1.78±0.7 and 2.43±0.5, p=0.002), interventricular septal thickness (11±1.7 mm and 12±1.47 mm, p=0.008), left ventricular posterior wall thickness (11±0.9 mm and 12±1.3 mm, p=0.007), and left ventricular mass (195±51 g and 181±37.9 g, p=0.028).

Conclusion:

According to the results, AF recurrence after ablation was found to be associated with the use of multiple antiarrhythmic drugs before the ablation, increased left atrial diameter, the reduced flow rate in the LAA, presence of a pulmonary venous anomaly, increased interventricular septal thickness, left ventricular posterior wall thickness, and left ventricular mass.

Keywords:

Atrial fibrillation, cryoballoon ablation, pulmonary vein isolation, left atrium

INTRODUCTION

Atrial fibrillation (AF) is a supraventricular arrhythmia occurring in the atrium that is associated with irregular ventricular responses. AF is the most common type of persistent cardiac arrhythmia observed in 1 to 2% of the general population¹. Although AF may lead to symptoms such as palpitations, fatigue, polyuria, dizziness, exertion dyspnea, chest pain, hypotension, and syncope, a significant proportion of patients with AF rhythm may be asymptomatic². AF is associated with a 5-fold increased risk of stroke³. Cardiac and non-cardiac factors associated with AF include chronic alcohol intake, cardiac valvular disease, CAD, heart failure (HF), left ventricular hypertrophy, diabetes mellitus (DM), HT, hyperthyroidism, pulmonary embolism, chronic obstructive pulmonary disease, surgical intervention, hypertrophic or dilated cardiomyopathy or congenital cardiac diseases^1,4. The triggering focus originates from the pulmonary veins (PV) in 90% of the cases with paroxysmal AF (PAF). Other identified foci include superior vena cava, coronary sinus, and the Marshall ligament^5,6. The primary therapeutic method in AF ablation is based on the electrical isolation of PVs from LA. The European Society of Cardiology 2016 AF guidelines recommend catheter ablation to be performed in specialized centers by properly trained electrophysiologists for patients with symptomatic PAF recurrences during antiarrhythmic therapy, for whom the preferred therapeutic modality is rhythm control treatment².

In this study, the predictors of AF recurrence were investigated in 68 patients who underwent cryoablation due to symptomatic PAF.

GİRİŞ

Atriyal fibrilasyon (AF), düzensiz ventriküler yanıtlarla ilişkili atriyumda meydana gelen supraventriküler bir aritmidir. AF, genel popülasyonun %1 ila %2’sinde gözlenen en yaygın kalıcı kardiyak aritmi türüdür¹. AF çarpıntı, yorgunluk, poliüri, baş dönmesi, efor dispnesi, göğüs ağrısı, hipotansiyon ve senkop gibi semptomlara yol açabilse de, AF ritmi olan hastaların önemli bir kısmı asemptomatik olabilir². AF, 5 kat artmış inme riski ile ilişkilidir³. Atriyal fibrilasyonla ilişkili kardiyak ve kardiyak olmayan faktörler arasında kronik alkol alımı, kalp kapak hastalığı, KAH, kalp yetmezliği (KY), sol ventrikül hipertrofisi, diabetes mellitus (DM), hipertansiyon (HT), hipertiroidizm, pulmoner emboli, kronik obstrüktif akciğer hastalığı, cerrahi müdahale, hipertrofik veya dilate kardiyomiyopati veya konjenital kalp hastalıkları yer alır^1,4. Paroksismal AF’li (PAF) olguların %90’ında tetikleyici odak pulmoner venlerden (PV) kaynaklanır. Tanımlanan diğer odaklar superior vena kava, koroner sinüs ve Marshall ligamentini içerir^5,6. AF ablasyonundaki birincil terapötik yöntem, PV’lerin LA’dan elektriksel izolasyonuna dayanır. Avrupa Kardiyoloji Derneği 2016 AF kılavuzları, antiaritmik tedavi sırasında semptomatik PAF nüksleri olan ve tercih edilen terapötik modalitenin ritim kontrol tedavisi olduğu hastalarda uzman merkezlerde uygun eğitimli elektrofizyologlar tarafından kateter ablasyonunun yapılmasını önermektedir².

Bu çalışmada semptomatik PAF nedeniyle kriyoablasyon uygulanan 68 hastada AF rekürrensinin öngördürücüleri araştırıldı.

MATERIALS AND METHODS

A retrospective file review was performed and outpatient medical records were evaluated, yielding the information of 68 patients who underwent cryoballoon ablation due to a diagnosis of symptomatic PAF between October 2013 and March 2016. Diagnoses of ischemic stroke or recurrent AF after the procedure were ascertained by telephone calls and through the review of clinical records. The first 3 months following the procedure were defined as the blind period and AF, atrial flutter, or episodes of atrial tachycardia during this period were considered as early AF recurrence. Episodes after the first 3 months were considered as recurrence.

Patients under 18 years of age and those with persistent AF, serious valvular disease, and thrombus in LA, pregnant women, and those with active neoplasm, prosthetic cardiac valve, implantable cardiac rhythm devices were excluded from the study.

In our center, procedures were performed under sedation with midazolam. The Seldinger technique was used for access via the left femoral vein and artery, and the right femoral vein. Access to the left atrium was performed under fluoroscopy with transseptal puncture with a modified Brockenborough needle accompanied by transesophageal echocardiography. The Flaxcath (metronik) brand steerable transseptal catheter was directed to the left atrium over the guide wire. Arctic front^® and arctic front advance^® (metronik) brand cryoablation balloon was directed through this sheath. PV circular mapping catheter through balloon the Achieve catheter was directed. Following left atrial puncture, anticoagulation was achieved using heparin with a target ACT of 300-350 seconds. After complete occlusion of PVs was ensured, a 5-minute standard cooling procedure was carried out by pumping a freezing agent (N2O) into the balloon. While ablation was performed in right PVs, continuous phrenic nerve stimulation at a low rate was performed in the superior vena cava, in conjunction with manual palpation of the contractions in the diaphragmatic area. After two freezing procedures with a minimum duration of five minutes in each PV, the procedure was terminated. One day after the cryoballoon ablation, transthoracic echocardiography was performed to rule out pericardial effusion, and patients were discharged. Treatment with oral anticoagulants and antiarrhythmic agents was planned to be continued for a minimum duration of 3 months following the cryoballoon ablation procedure, after which anticoagulant treatment was scheduled based on the CHA2DS2-VASc risk assessment.

The study was approved by the Uludağ University Local Ethics Committee for Clinical Research with decree no: 2016-5/21 and approval date: 29.11.2019.

Statistical Analysis

Statistical Package for Social Sciences for Windows 23.0 software pack was used for the statistical assessment. Descriptive statistics were expressed as mean, standard deviation, median, minimum, and maximum. Categorical variables were expressed as numbers and percentages. The Shapiro-Wilk test was used to test whether the data had a normal distribution. The t-test was employed for variables with normal distribution and the Mann-Whitney U test was used for comparisons between the two groups. Logistic regression analysis was performed to evaluate the association between variables tested and the recurrence. A p value <0.05 was considered statistically significant.

RESULTS

A total of 68 patients undergoing cryoablation due to PAF between October 2013 and March 2016 were included in the study. Patients were followed up for a mean duration of 22 months (8-37). The 68 patients included in the study were stratified into two groups as those who had AF recurrence and those who remained in sinus rhythm after the blind period of the initial three months. Of the 68 patients in the study, 32 (47.1%) were male and 36 (52.9%) were female. The mean age of the overall patient group was 57.3±12 years. With regards to cardiovascular risk factors, 25 patients (36.8%) had CAD, 9 (13.2%) had DM, 46 (67.6%) had HT, and 3 (4.4%) had a history of cerebrovascular event. Among all patients, the mean CHA2DS2-VASc score was 2.2±1.39, and the mean number of antiarrhythmic drugs the patients received was 1.94±0.7 (0-3) (Table 1).

Transthoracic echocardiography and transesophageal echocardiography performed before the procedure showed a median LA size, left ventricular ejection fraction, and LAA flow rate of 39.5±6.0 mm, 62±5.7%, and 36.5 (22-62) cm/sec, respectively. The median duration of fluoroscopy was 14±2.5 minutes. The success rate defined as successful ablation in three or PVs was 100%. PV anomaly (left or right-sided common PV) was identified in eleven patients (16.2%).

During the early period involving the initial three months, AF recurrence was found in 16 patients (23.5%), while 52 (76.5%) remained in the sinus rhythm during the follow-up. According to the evaluation of demographic characteristics of the patients, of the 16 patients with AF recurrence, 5 (31.3%) were female and 11 (68.7%) were male, while the corresponding figures among the 52 subjects with no recurrence included 31 (59.6%) female and 21 (40.4%) male. There were no statistically significant differences between the groups with regards to gender distribution (p>0.05) (Table 2).

Again, no statistical differences between patients who had or did not have AF recurrence were observed in terms of cardiovascular risk factors such as diabetes, hypertension, hyperlipidemia, coronary artery disease, and cerebrovascular event history (p>0.05) (Table 2).

Before the procedure, the number of antiarrhythmic drugs the patients received was 2.43±0.5 (2-3) and 1.78±0.7 (0-3) in those with and without AF recurrence, respectively. The number of antiarrhythmic drugs used before the procedure was significantly higher among patients who developed AF recurrence compared to those who did not (p=0.002) (Table 2).

Of the 16 patients with AF recurrence, 37.5% (6) had an AF episode during the early period of the first three months while this percentage was 11.5% (6) among the 52 patients who had no AF episodes during the same period. An AF episode during the early period of the first three months was a significant predictor for AF recurrence (p=0.027). The number of prior cardioversions was significantly higher among those with AF recurrence than those without AF recurrence (p<0.001) (Table 2).

LA diameter in patients with and without AF recurrence was 44±6.6 mm and 38±5.3 mm, respectively. LA diameter was higher in the group with AF recurrence compared to the group without AF recurrence with a statistically significant difference (p=0.003). Septum and posterior wall thickness of the left ventricle measured in the parasternal long-axis were found to be statistically significant in predicting AF recurrence (p=0.008 and 0.007, respectively). LV mass in patients with and without AF recurrence was 195±51 g and 181±37.9 g, respectively. The difference in LV mass between the two groups was statistically significant (p=0.028). LAA flow rate determined by transesophageal echocardiography in patients with and without AF recurrence was 28 (22-55) cm/sec and 38 (24-62) cm/sec, respectively. The difference in LAA flow rate between the two groups was statistically significant (p<0.001) (Table 3).

While six patients (37.5%) had a pulmonary anomaly in the AF recurrence group, the number of corresponding figures was five (9.6%) among those without AF recurrence. Pulmonary anomalies were more common in the group with AF recurrence compared to the group without AF, with a statistically significant difference (p=0.016) (Table 4).

No statistically significant difference was found between the patients who did or did not develop AF recurrence in terms of laboratory parameters such as complete blood count, renal function tests, thyroid function tests, C-reactive protein, erythrocyte sedimentation rate, and uric acid (p>0.05) (Table 5).

DISCUSSION

PV isolation for the management of PAF is performed either by radiofrequency (RF) or cryoballoon ablation. The reported success rate for ablation in patients with persistent AF is lower compared to that in PAF patients. In a meta-analysis involving 63 studies of RF ablation, success rates in paroxysmal and persistent AF were 70% and 14.9%, respectively⁷.

Excluding the first 3 months, 76.5% of the patients with PAF in the present study were AF-free during a median follow-up of 22 months. In the STOP-AF study comparing cryoballoon ablation and antiarrhythmic medication, 69.9% of the patients in the ablation group were AF-free during the twelve months of follow-up⁸. In a prospective multi-center study by Stabile et al.⁹, the success rate at one year of follow-up was 56% in the ablation group. The slightly higher success rate in the present study might have potentially resulted from the lower number of patients with structural heart disease, the relatively normal left atrium dimensions, and the small sample size.

In the above-mentioned meta-analysis of 63 studies investigating RF ablation, the reported rate of major complications was 4.9%, with PV stenosis (1.6%), pericardial effusion (0.6%), and thromboembolism (0.3%), which are the most frequent complications⁷. In another study on cryoablation, the rates of ischemic stroke, cardiac tamponade, and PV stenosis were reported as 0.3%, 0.3%, and 0.17%, respectively¹⁰. In the present study, none of the patients had major complications such as PV stenosis, cardiac tamponade, stroke, or death. Again, the lower complication rate in this study compared to the published data may be associated with the expertise level of our center in cryoballoon ablation for AF treatment, the limited number of patients, the inclusion of younger patients, and the lower number of comorbidities.

Pericardial effusion and phrenic nerve injury represent relatively more common complications of cryoablation. In the FIRE and ICE¹¹ study, phrenic nerve injury was reported in 2.3% of the cases. In the present study, 2 patients had pericardial effusion. Since none of the patients had the signs of cardiac tamponade, pericardiocentesis was not required.

Previously, an anterior-posterior LA diameter in the parasternal long-axis exceeding 45 mm was reported to be predictive for AF recurrence¹². Aytemir et al.¹³ identified LA diameter as an independent predictor for AF recurrence in their study evaluating efficacy and safety endpoints after PV isolation with cryoablation. In the present study, the mean LA diameter in patients with and without AF recurrence was 44±6.6 and 38±5.3 mm, respectively. LA dimensions were predictive for long-term AF recurrence after cryoablation. This observation supports the notion that LA dimensions should be a part of the patient selection process before cryoablation procedures.

Patients with high LAA emptying and filling rates determined by transesophageal echocardiography were found to remain in sinus rhythm for longer periods during their follow-up¹⁴. In a multi-center prospective study, the LAA emptying rate of less than 40 cm/sec was the single most important predictor of AF recurrence within 1 year¹⁵. In the current study, patients who developed recurrent AF had a 28 cm/sec (22-55) LAA flow rate determined by transesophageal echocardiography before cryoablation. A low LAA flow rate correlated with a higher likelihood of late AF recurrence. In line with the previous reports, this observation points out the role of a high LAA flow rate in maintaining the sinus rhythm.

AMIO-CAT¹⁶ and EAST-AF¹⁷ studies found that short-term antiarrhythmic treatment after AF ablation did not affect long-term AF recurrence although it might reduce the frequency of atrial tachyarrhythmia during the first 3 months. Lee et al.¹⁸ found late AF recurrence among 35 of the 81 patients (43%) who developed early recurrence. Aytemir et al.¹³ observed early AF recurrence in 29.1% of the patients who had AF recurrence after PV isolation with cryoablation. In the present study, 37.5% of the patients with late AF recurrence had an early AF episode, supporting the notion that early AF episodes may predict late AF recurrences.

Kubala et al.¹⁹ performed cryoablation in 118 patients with drug-resistant PAF and found that atypical PV anatomy involving a common left PV was associated with an increased risk of AF recurrence compared to normal PV anatomy. There were 11 patients with PV anomalies in the present study. The rate was 37.5%⁶ and 9.5%⁵ in the group with AF recurrence and in the group with maintained sinus rhythm, respectively. The presence of a common PV was associated with AF recurrence. This observation suggests that cryoablation may be associated with lower success rates among patients with PV anomalies.

In the study by Evranos et al.²⁰, several biomarkers including C-reactive protein and erythrocyte sedimentation rate were found to not affect the risk of AF recurrence. Similarly, C-reactive protein and erythrocyte sedimentation rate measurements performed before cryoablation showed no association with AF recurrence in the present study.

Due to financial reasons, we could not use the three dimensional mapping system for ablation in our center. The three dimensional catheter navigation techniques can be applied to facilitate accurate catheter positioning with limited fluoroscopic exposure. The three dimensional mapping systems allow a better understanding of the anatomy and the pathophysiology of the arrhythmia²¹. In the complex patients, the combination of the three dimensional mapping system with image integration and remote magnetic navigation have been shown to be useful to facilitate ablation with very low fluoroscopy exposure. Integration of the fluoroscopy into the mapping system allows better understanding of the anatomy and might be associated with a better safety profile due to continuous catheter visualization during ablation²².

Study Limitations

This study had several limitations. This was a retrospective analysis. Because of the sample size, future studies of larger cohorts with more statistical power were needed to validate the findings. Some patients had a relatively short follow-up duration (8 months), and the predictive significance of the specified factors in patients with recurrent AF warrants further evaluation. Some asymptomatic AF cases may not have been included in the study.

TARTIŞMA

PAF’nin yönetimi için PV izolasyonu, radyofrekans (RF) veya kriyobalon ablasyonu ile gerçekleştirilir. Kalıcı AF hastalarında ablasyon için bildirilen başarı oranı, PAF hastalarına kıyasla daha düşüktür. RF ablasyonu ile ilgili 63 çalışmayı içeren bir meta-analizde, paroksismal ve persistan AF’de başarı oranları sırasıyla %70 ve %14,9’dur⁷.

İlk 3 ay hariç tutulduğunda, bu çalışmada PAF’si olan hastaların %76,5’inde medyan 22 aylık takip sırasında AF gelişmedi. Kriyobalon ablasyonu ve antiaritmik ilaç tedavisini karşılaştıran STOP-AF çalışmasında, ablasyon grubundaki hastaların %69,9’unda on iki aylık takip süresince AF gelişmedi⁸. Stabile ve ark.’nın⁹ prospektif çok merkezli çalışmasında, ablasyon grubunda bir yıllık takipteki başarı oranı %56 idi. Bu çalışmadaki biraz daha yüksek başarı oranı, potansiyel olarak yapısal kalp hastalığı olan hasta sayısının daha az olmasından, nispeten normal sol atriyum boyutlarından ve küçük örneklem büyüklüğünden kaynaklanmış olabilir.

RF ablasyonunu araştıran 63 çalışmanın yukarıda bahsedilen meta-analizinde, PV stenozu (%1,6), perikardiyal efüzyon (%0,6) ve tromboembolizm (%0,3) ile bildirilen majör komplikasyon oranı %4,9 idi. Bunlar en sık görülen komplikasyonlardır⁷. Kriyoablasyon ile ilgili başka bir çalışmada iskemik inme, kardiyak tamponad ve PV darlığı oranları sırasıyla %0,3, %0,3 ve %0,17 olarak bildirilmiştir¹⁰.

Bu çalışmada, hastaların hiçbirinde PV stenozu, kardiyak tamponad, inme veya ölüm gibi majör komplikasyonlar görülmedi. Yine bu çalışmada, yayınlanan verilerle karşılaştırıldığında komplikasyon oranının daha düşük olması, merkezimizin AF tedavisi için kriyobalon ablasyonundaki uzmanlık düzeyi, hasta sayısının sınırlı olması, daha genç hastaların dahil edilmesi ve daha az sayıda komorbidite ile ilişkilendirilebilir.

Perikardiyal efüzyon ve frenik sinir hasarı, kriyoablasyonun nispeten daha yaygın komplikasyonlarını temsil etmektedir. FIRE ve ICE¹¹ çalışmasında olguların %2,3’ünde frenik sinir yaralanması bildirilmiştir. Bu çalışmada 2 hastada perikardiyal efüzyon vardı. Hiçbir hastada kardiyak tamponad bulguları olmadığı için perikardiyosentez gerekmedi.

Daha önce, 45 mm’yi aşan parasternal uzun eksende ön-arka LA çapının AF rekürrensi için öngörücü olduğu bildirilmişti¹². Aytemir ve ark.¹³ kriyoablasyon ile PV izolasyonundan sonra etkinlik ve güvenlik son noktalarını değerlendiren çalışmalarında AF nüksü için bağımsız bir öngörücü olarak LA çapını tanımladılar. Bu çalışmada AF nüksü olan ve olmayan hastalarda ortalama LA çapı sırasıyla 44±6,6 ve 38±5,3 mm idi. LA boyutları, kriyoablasyondan sonra uzun süreli AF nüksü için öngörücüydü. Bu gözlem, kriyoablasyon prosedürlerinden önce LA boyutlarının hasta seçim sürecinin bir parçası olması gerektiği fikrini desteklemektedir.

Transözofageal ekokardiyografi ile belirlenen LAA boşalma ve dolum oranları yüksek olan hastaların takiplerinde daha uzun süre sinüs ritminde kaldıkları görülmüştür¹⁴. Çok merkezli prospektif bir çalışmada, 40 cm/saniyeden daha az LAA boşalma hızı, 1 yıl içinde AF rekürrensinin en önemli yordayıcısı idi¹⁵. Bu çalışmada, tekrarlayan AF gelişen hastalarda, kriyoablasyon öncesi transözofageal ekokardiyografi ile belirlenen 28 cm/saniye (22-55) LAA akış hızı vardı. Düşük bir LAA akış hızı, daha yüksek bir geç AF nüksü olasılığı ile ilişkilidir. Önceki raporlarla uyumlu olarak, bu gözlem sinüs ritminin korunmasında yüksek bir LAA akış hızının rolüne işaret etmektedir.

AMIO-CAT¹⁶ ve EAST-AF¹⁷ çalışmaları, AF ablasyonundan sonra kısa süreli antiaritmik tedavinin, ilk 3 ayda atriyal taşiaritmi sıklığını azaltabilmesine rağmen, uzun süreli AF nüksünü etkilemediğini bulmuştur. Lee ve ark.¹⁸ erken nüks gelişen 81 hastanın 35’inde (%43) geç AF nüksü saptamıştır. Aytemir ve ark.¹³ kriyoablasyon ile PV izolasyonu sonrası AF nüksü olan hastaların %29,1’inde erken AF nüksü gözlemlemişlerdir. Bu çalışmada, geç AF nüksü olan hastaların %37,5’inde erken AF atağı görülmüştür, bu da erken AF ataklarının geç AF nükslerini öngörebileceği fikrini desteklemektedir.

Kubala ve ark.¹⁹ ilaca dirençli PAF’si olan 118 hastada kriyoablasyon uygulamışlar ve ortak bir sol PV içeren atipik PV anatomisinin, normal PV anatomisine kıyasla artmış AF nüksü riski ile ilişkili olduğunu bulmuşlardır. Bu çalışmada PV anomalisi olan 11 hasta vardı. AF nüksü olan grupta bu oran %37,5⁶ ve sinüs ritmi korunan grupta %9,5⁵ idi. Ortak bir PV’nin varlığı AF nüksü ile ilişkilendirildi. Bu gözlem, kriyoablasyonun PV anomalisi olan hastalarda daha düşük başarı oranları ile ilişkili olabileceğini düşündürmektedir.

Evranos ve ark.’nın²⁰ çalışmasında, C-reaktif protein ve eritrosit sedimantasyon hızı dahil olmak üzere çeşitli biyobelirteçlerin AF tekrarlama riskini etkilemediği bulundu. Benzer şekilde, kriyoablasyon öncesi yapılan C-reaktif protein ve eritrosit sedimantasyon hızı ölçümleri, bu çalışmada AF nüksü ile ilişki göstermedi.

Maddi nedenlerden dolayı merkezimizde ablasyon için üç boyutlu haritalama sistemini kullanamadık. Sınırlı floroskopik maruziyetle doğru kateter konumlandırmayı kolaylaştırmak için üç boyutlu kateter navigasyon teknikleri uygulanabilir. Üç boyutlu haritalama sistemleri, aritminin anatomisinin ve patofizyolojisinin daha iyi anlaşılmasını sağlar²¹. Karmaşık hastalarda, görüntü entegrasyonu ve uzaktan manyetik navigasyon ile üç boyutlu haritalama sisteminin kombinasyonunun, çok düşük floroskopi maruziyeti ile ablasyonu kolaylaştırmak için faydalı olduğu gösterilmiştir. Floroskopinin haritalama sistemine entegrasyonu, anatominin daha iyi anlaşılmasını sağlar ve ablasyon sırasında sürekli kateter görüntüleme nedeniyle daha iyi bir güvenlik profili ile ilişkilendirilebilir²².

Çalışmanın Kısıtlılıkları

Bu çalışmanın birkaç sınırlılığı vardı. Bu çalışma retrospektif bir analizdi. Örneklem büyüklüğü nedeniyle, bulguları doğrulamak için daha fazla istatistiksel güce sahip daha büyük kohortların gelecekteki çalışmalarına ihtiyaç vardı. Bazı hastaların takip süresi nispeten kısaydı (8 ay) ve tekrarlayan AF’si olan hastalarda belirtilen faktörlerin prediktif önemi daha fazla değerlendirmeyi desteklemektedir. Bazı asemptomatik AF olguları çalışmaya dahil edilmemiş olabilir.

CONCLUSION

Cryoablation is widely used for the treatment of AF worldwide. The safety and efficacy of this method have been established in several studies. However, the efficacy may vary depending on the expertise level of the operator, ablation technique, and catheter technology. Based on the results of the present study, several factors, including the occurrence of early AF episodes, history of cardioversion, use of multiple antiarrhythmic drugs before the procedure, high LA diameter, low LAA flow rate, presence of PV anomaly, increased interventricular septal thickness, left ventricular posterior wall thickness, and left ventricular mass, were predictive for AF recurrence during follow up after cryoablation We believe that consideration of these factors during patient selection may improve the success rate of this procedure.

Ethics

Ethics Committee Approval: The study was approved by the Uludağ University Local Ethics Committee for Clinical Research with decree no: 2016-5/21 and approval date: 29.11.2019.

Informed Consent: Retrospective study.

Peer-review: Externally peer-reviewed.

Authorship Contributions

Surgical and Medical Practices: E.Ç., A.A., Concept: A.D., S.Ç., F.B., A.A., Design: E.Ç., A.A., Data Collection or Processing: E.Ç., Analysis or Interpretation: A.D., S.Ç., F.B., A.A., Literature Search: E.Ç., A.D., S.Ç., F.B., A.A., Writing: E.Ç., A.D., S.Ç., F.B., A.A.

Conflict of Interest: No conflict of interest was declared by the authors.

Financial Disclosure: The authors declared that this study received no financial support.

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