|Year : 2019 | Volume
| Issue : 2 | Page : 55-60
Electrophysiological and anatomical characteristics of pulmonary vein isolation with “crosstalk” effect during cryoballoon ablation (English version)
Lina Ma1, Jian Ma2, Huiqiang Wei2, Jiandu Yang2, Qi Sun2, Haiyang Xie2, Chao Li2
1 Center of Arrhythmia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing; Department of Cardiology, The Second People's Hospital of Dingxi, Dingxi, Gansu Province, China
2 Center of Arrhythmia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing, China
|Date of Submission||13-Mar-2020|
|Date of Acceptance||25-Apr-2020|
|Date of Web Publication||15-Jun-2020|
Dr. Jian Ma
Center of Arrhythmia, Fuwai Hospital, National Center for Cardiovascular Diseases, Chinese Academy of Medical Sciences, Peking Union Medical College, Beijing 100037
Source of Support: None, Conflict of Interest: None
Background: We aimed to explore the electrophysiological and left atrial anatomical characteristics of pulmonary vein isolation with the “crosstalk” technique during second-generation cryoballoon ablation and figure out a better practice of this technique. Subjects and Methods: A total of 504 patients (311 males and 193 females) with atrial fibrillation were included. All of these patients underwent initial ablation with second-generation cryoballoon. Among these patients, 89 patients (17.7%) did not achieve left/right superior pulmonary vein (LSPV/RSPV) isolation during first cryoablation. In the crosstalk group, there were 35 (39.3%) patients had “crosstalk” phenomenon. The remaining 54 patients (60.7%) without “crosstalk” were included in the control group. The baseline data, electrophysiological and anatomic characteristics of the left atrium were compared between crosstalk group and control group. The study was approved by the Ethics Committee of Fuwai Hospital, China. Results: In the crosstalk group, 33 patients (94.3%) had “crosstalk” phenomenon in the LSPV. The percentage of pulmonary vein potential (PVP) delay during first cryoablation was significantly increased in the crosstalk group compared with the control group (100% vs. 72.2%, P < 0.05). The total ablation time and frequency were significantly decreased in the crosstalk group compared with the control group (P < 0.05). As for the anatomic characteristics, the average distance from LSPV to inferior pulmonary vein, average distance of RSPV and inferior pulmonary veins were significantly shorter in the crosstalk group compared with the control group (P < 0.05). Conclusion: The “crosstalk” phenomenon was more frequent in the left pulmonary vein. Short distance between superior and inferior pulmonary vein and PVP delay during ablation could predict the “crosstalk” phenomenon.
Keywords: Anatomical characteristics, atrial fibrillation, crosstalk, cryoballoon, pulmonary vein isolation
|How to cite this article:|
Ma L, Ma J, Wei H, Yang J, Sun Q, Xie H, Li C. Electrophysiological and anatomical characteristics of pulmonary vein isolation with “crosstalk” effect during cryoballoon ablation (English version). Int J Heart Rhythm 2019;4:55-60
|How to cite this URL:|
Ma L, Ma J, Wei H, Yang J, Sun Q, Xie H, Li C. Electrophysiological and anatomical characteristics of pulmonary vein isolation with “crosstalk” effect during cryoballoon ablation (English version). Int J Heart Rhythm [serial online] 2019 [cited 2020 Oct 28];4:55-60. Available from: https://www.ijhronline.org/text.asp?2019/4/2/55/286763
This manuscript is an English version based on Ma L, Ma J, Wei H, Yang J, Sun Q, Xie H, Li C. Electrophysiological and anatomical characteristics of pulmonary vein isolation with “crosstalk” effect during cryoballoon ablation. Chin J Cardiac Arrhyth 2020;24(1):14-20. DOI: 10.3760/cma.j.issn.1007-6638.2020.01.004. The second publication of this manuscript has obtained the permission from Chinese Journal of Cardiac Arrhythmias.
| Introduction|| |
The clinical efficacy of pulmonary vein isolation (PVI) in the treatment of paroxysmal atrial fibrillation (AF) is not inferior to radiofrequency ablation under the guidance of three-dimensional mapping system., Compared with the first-generation cryoballoon, the second-generation cryoballoon has larger freezing range and stronger freezing effect, which further improves the effect of PVI. However, stronger freezing effect is bound to increase the damage to adjacent tissues and organs. It is reported that the incidence of complications such as atrioesophageal fistula, phrenic nerve paralysis, and bronchial mucosal injury in the second generation cryoballoon is higher than that of the first generation cryoballoon.,,, Therefore, it is very necessary to apply certain operation skills to reduce the time and frequency of cryoballoon ablation. For example, in some patients, there are “crosstalk” effects in the process of PVI, showing that when the superior pulmonary vein is not electrically isolated, while cryoballoon ablation and electrical isolation of the ipsilateral inferior pulmonary vein, the electrical isolation effect of the superior pulmonary vein also appears. This study summarizes and analyzes the electrophysiological and anatomical characteristics of pulmonary vein during the treatment of paroxysmal AF with the second-generation cryoballoon.
| Subjects and Methods|| |
From August 2016 to December 2017, 504 patients (311 males and 193 females) with paroxysmal AF in the second arrhythmia ward of Fuwai Hospital were analyzed retrospectively. The patients received PVI with sinus rhythm during the operation using 28 mm second generation cryoballoon. The exclusion criteria were as follows: previous left atrial catheter ablation, pulmonary vein common trunk, anticoagulation taboo, left atrial diameter >50 mm, left atrial thrombosis, decompensated heart failure. The “crosstalk” effect is defined as when the superior pulmonary vein is not electrically isolated, while cryoablation and electrical isolation of the ipsilateral inferior pulmonary vein, the electrical isolation effect of the superior pulmonary vein also occurs., Those patients having no crosstalk effect were classified as control group showing that while the inferior pulmonary vein was isolated by cryoablation, there was no electrical isolation of the ipsilateral superior pulmonary vein. The baseline data, left atrium-pulmonary vein anatomy, intraoperative pulmonary vein potential (PVP) changes and pulmonary vein cryoballoon ablation time and frequency were compared between the two groups. According to the guidelines, all patients were clearly diagnosed as paroxysmal AF and were ineffective by antiarrhythmic drugs and had indications for catheter ablation. All patients signed an informed consent form before operation, and the study was approved by the Ethics Committee of Fuwai Hospital and in line with the principles of the Declaration of Helsinki.
All patients underwent transesophageal echocardiography to exclude left atrial thrombus before operation. If patients take warfarin, they will stop to use it 3 days before operation and change to low molecular weight heparin bridging anticoagulant. If patients take new oral anticoagulants (e.g. rivasaban and dabigagarate), they will not receive low molecular weight heparin bridging anticoagulation. Administration of class I or III antiarrhythmic drugs will be stopped for at least 5 half-lives before operation. All patients underwent left atrium-pulmonary vein computed tomography before operation to determine the anatomical morphology of pulmonary vein and transthoracic echocardiography to determine left atrial diameter, left ventricular end-diastolic diameter (LVEDD), and left ventricular ejection fraction (LVEF).
Midazolam and fentanyl were injected intravenously to make the patients gradually fall into deep sleep, and the vital signs such as heart rate, blood pressure, and blood oxygen saturation were monitored. A 10-pole catheter was placed through the right internal jugular vein to the coronary sinus, and a 4-pole catheter was placed through the left femoral vein to the right heart. The 4-pole catheter was sent to the superior vena cava for phrenic nerve pacing before cryoballoon ablation of the right pulmonary vein. Atrial septal puncture was performed through the right femoral vein. After successful puncture, 100 IU/kg unfractionated heparin was given through the sheath. Meanwhile, left atrium-pulmonary venography was performed, combined with three-dimensional anatomical reconstruction images to determine the location of pulmonary vein orifice and antrum. The SL1 long sheath was replaced by 15F adjustable curved sheath (FlexCath Advance, Medtronic, Minneapolis, MN, USA) through the guide wire. A 28 mm cryoballoon (Arctic Front Advance, Medtronic) with 8-pole annular catheter (Achieve, Medtronic) was inserted into the sheath to the left atrium. The annular catheter was sent to the orifice of the pulmonary vein to record the PVP. The cryoballoon ablation sequence was upper left, lower left, upper right and right inferior pulmonary vein. If the pulmonary vein is blocked satisfactorily, it will begin to cryoballoon ablation. If vagus nerve reflex occurs during cryoballoon ablation, right ventricular electrode should be used for pacing. When necessary, cimetidine (5–10 mg) should be given. Continuous phrenic nerve pacing (current 20 mA, pulse width 2 ms) is necessary during ablation of right superior and inferior pulmonary veins to monitor diaphragm movement. Once diaphragm movement weakens, ablation will be stopped immediately until diaphragm movement returns to normal. The cryoballoon ablation time of pulmonary vein was 180 seconds. The end point of ablation was electrical isolation of pulmonary vein from pulmonary vein to left atrium. If the potential of the superior pulmonary vein is not isolated after the first cryoballoon ablation, the cryoballoon ablation of the inferior pulmonary vein is continued [
[Figure 1]. The activated prothrombin time was measured during the operation and maintained for more than 300 seconds.
|Figure 1: Example of left superior pulmonary vein cryoballoon ablation using “crosstalk” technique. (a) Left atrium-pulmonary vein angiography suggested a short distance between the superior and inferior pulmonary veins. (b) Delayed pulmonary vein potential (arrow) occurred after left superior pulmonary vein cryoballoon ablation. (c and d) Electrical isolation of left superior pulmonary vein potential was detected after cryoballoon ablation of left inferior pulmonary vein. CS=Coronary sinus; Ach=Annular catheter; p=Proximal; d=Distal|
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Intraoperative cryoballoon ablation parameters
The real-time recording rate of each PVP, isolation time, isolation temperature, minimum temperature and other freezing parameters during cryoballoon ablation were recorded. At the same time, the occurrence of vagal reflex, diaphragmatic paralysis and cough were also recorded. The operation time, X-ray exposure time and X-ray exposure were recorded after operation.
Anatomical analysis of pulmonary vein
Three-dimensional reconstruction of left atrium and pulmonary vein was performed by Carto system (Johnson and Johnson Services Inc., New Brunswick, NJ, USA). The orifice of pulmonary vein was defined as the junction of pulmonary vein and left atrium. The orifice of the left pulmonary vein included the key points such as left posterior parietal, left anterior parietal, left anterior bottom, left posterior wall, left inferior bottom and left anterior wall (ridge), while the right pulmonary vein orifice located the key points such as right anterior parietal, right anterior wall, right inferior bottom, right posterior wall and so on [Figure 2]. After determining the orifice of the pulmonary vein, the shortest distance of the left superior and inferior pulmonary vein orifice was measured through the posterior anterior position and the left lateral position and the right superior and inferior pulmonary vein orifice was measured through the posterior anterior position and the right lateral position [Figure 3].
|Figure 2: Three-dimensional reconstruction of left atrium and pulmonary vein and location of the pulmonary vein orifice. (a–c) Location of left pulmonary vein orifice: Left posterior parietal (1), left inferior wall (2), left inferior bottom (3), left anterior bottom (4), and left anterior wall (5), and left anterior parietal (6). (d–f) Location of right pulmonary vein orifice: Right anterior parietal (1), right anterior wall (2), right inferior bottom (3), right posterior wall (4). PA=Posterior anterior position, LL=Left lateral position, AP=Anterior posterior position, RL=Right lateral position|
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|Figure 3: Three-dimensional reconstruction of left atrium-pulmonary vein and measurement of the distance between superior and inferior pulmonary vein. Shorter distance between left and right pulmonary vein antrum was seen in the crosstalk group (a and c) compared with the control group (b and d)|
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SPSS 20 statistical software (IBM, Armonk, NY, USA) was used. The continuous variables in accordance with the normal distribution are represented by mean ± standard deviation, and the independent sample t-test is used for the comparison between variables. The continuity of nonnormal distribution is expressed by the median (5% and 95% quantiles), and the comparison between variables is expressed by nonparametric test. The categorical variables are expressed as a percentage and the Chi-square test is applied. A P < 0.05 indicates a statistically significant difference.
| Results|| |
Of the 504 patients, 89 cases failed to isolate the superior pulmonary vein during the first cryoballoon ablation, including 52 of left superior pulmonary vein (LSPV) and 37 of right superior pulmonary vein (RSPV). Among them, 35 patients had “crosstalk” effects (crosstalk group). In the crosstalk group, there were 33 cases of LSPV and 2 cases of RSPV. Among 54 cases without “crosstalk” effect (control group), 7 used 23 mm cryoballoon to achieve superior PVI, 13 used radiofrequency ablation complement to accomplish PVI, 34 succeeded in pulmonary vein electrical isolation after repeated cryoballoon ablation of superior pulmonary vein. There was no significant difference in age, sex, course of AF, left atrial diameter, LVEDD, LVEF, CHA2 DS2-VASc (cardiac failure or dysfunction, hypertension, age ≥75 [doubled], diabetes, stroke [doubled]-vascular disease, age 65–74 years and sex category [female]) score between the two groups [Table 1].
|Table 1: Comparison of baseline data between the crosstalk and control groups|
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Intraoperative data of cryoballoon ablation
PVP could be recorded in all patients. All patients in the crosstalk group (100%) had delayed superior PVP after cryoballoon ablation and the delayed upper PVP at the bottom of the circular catheter was earlier. In the control group, only 39 cases (72.2%) had delayed superior pulmonary venous potential, and only 15 cases (27.8%) [Table 2]. The total time of LSPV cryoballoon ablation in the crosstalk group was significantly shorter than in the control group (P < 0.05), and the frequencies of LSPV cryoballoon ablation in crosstalk group was significantly less than in the control group (P < 0.05).
|Table 2: Comparison of superior pulmonary vein delayed potential and intraoperative data of cryoballoon ablation between the crosstalk and control groups|
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Anatomical characteristics of left atrium-pulmonary vein
The average distance between left superior and inferior pulmonary veins in the crosstalk group was significantly shorter than that in the control group (6.12 ± 1.19 mm vs. 7.63 ± 1.39 mm, P < 0.05), and the average distance between the right superior and inferior pulmonary veins in the crosstalk group was also significantly shorter than that in the control group (6.25 ± 0.21 mm vs. 8.44 ± 1.58 mm, P < 0.05). The average distance between the left superior and inferior pulmonary veins was shorter than that between the right superior and inferior pulmonary veins (6.68 ± 1.45 mm vs. 8.32 ± 1.61 mm, P < 0.05).
| Discussion|| |
Based on the theory that pulmonary vein triggers AF, PVI has become the cornerstone of the treatment of AF at present. Second generation cryoballoon which is used to isolate pulmonary vein has a great advantage over the first generation cryoballoon in terms of immediate success rate and long-term recurrence rate.,,,,,, But even so, PVI is often not completed in a single cryoballoon ablation, and some pulmonary veins may need to undergo multiple cryoballoon ablation. The proportion of disposable PVI of single pulmonary vein using second generation cryoballoon in our center: LSPV 71.4%, left inferior pulmonary vein 78.7%, RSPV 82.3%, and right inferior pulmonary vein 71.3%. The average single pulmonary vein one-time PVI is about 75.9%. The increase in the proportion of single pulmonary vein single or double PVI is positive for reducing adjacent organ damage, shortening the total operation time and X-ray exposure time. The difficulty of PVI is related to the size of left atrium, shape of pulmonary vein, location of orifice, proximal branch, puncture point, and other factors. The above factors will affect the placement of the cryoballoon catheter, the stability, the difficulty of operation, the depth of entering the orifice of the pulmonary vein and the degree of adhesion between the cryoballoon and the tissue surface. For the pulmonary vein which is difficult to operate, in order to form continuous and circular injury without increasing complications, it is often necessary to use some special ablation techniques to isolate the superior pulmonary vein. Different operators have different application experience. In this study, 35 of 89 patients achieved PVI by “crosstalk” effect. Compared with the other patients with no “crosstalk” effect combined with use of 23 mm cryoballoon, compensatory radiofrequency ablation and subsequent cryoballoon ablation of superior pulmonary vein to complete PVI, the time and frequency of cryoablation, the cost of operation and the risk of operation in the crosstalk group were reduced in varying degrees.
In 35 patients with “crosstalk” effect, although the complete PVI could not be achieved, the delayed PVP was recorded after 180 seconds cryoballoon ablation. On the contrary, 15 patients with no recording of delayed PVP had no “crosstalk” effect. Thus it can be seen that the delay of superior PVP is the premise of interaction. The potential delay indicates that the surface of the cryoballoon is well attached to the top of the pulmonary vein, and the tissue is in close contact with the top of the pulmonary vein. If the tissue is not close to the bottom, intraoperative pulmonary venography shows that there is a reflux of contrast medium at the bottom of the pulmonary vein. At this time, if the operator frequently adjusts the position of the cryoballoon catheter, or if the cryoballoon catheter is too deep into the orifice of the pulmonary vein, it is bound to isolate the pulmonary vein after the freezing injury at the bottom reaches the standard. However, the incidence of pulmonary vein stenosis, bronchial mucosal injury, vagal reflex and diaphragmatic nerve anesthesia will increase. According to the experience of our center, the cryoinjury of the base of the superior pulmonary vein can be consolidated by “crosstalk” effect during the cryoballoon ablation of the inferior pulmonary vein, resulting in continuous, uniform and irreversible tissue injury of the whole superior pulmonary vein. The superior and inferior pulmonary veins were electrically isolated at the same time. The absence of potential delay suggests that the top of the pulmonary vein does not achieve transmural injury, so it is impossible to interact with the inferior pulmonary vein by cryoballoon ablation. Compared with the crosstalk group, the control group had longer freezing time and more freezing numbers of the LSPV. There are two reasons: first, the shape of pulmonary vein in the control group is poor resulting in several try of the superior pulmonary vein cryoballoon ablation; second, the pulmonary vein antrum is easy to form arrhythmic matrix. Therefore, 13 patients in the control group had undergone cryoballoon ablation of the pulmonary vein antrum. In this study, 74 patients had delayed PVP after cryoballoon ablation, of which 35 cases had “crosstalk” effect and 39 cases had no “crosstalk” effect, that is to say, myocardial transmural injury could not be caused at the junction of ipsilateral inferior pulmonary vein. Through the comparison of the anatomical structure of pulmonary vein and left atrium between the two groups and the analysis of delayed potential, we found that in the crosstalk group, the potential delay of superior pulmonary vein recorded by circular mapping catheter was located at the base of superior pulmonary vein, and the distance between superior and inferior pulmonary veins was significantly shorter than that of control group. Yang et al. reported that the incidence of “crosstalk” effect of the second generation balloon was higher than that of the first generation balloon, and factors such as small distance between pulmonary veins, small angle between left atrial parietal and superior pulmonary vein, co-trunk of pulmonary vein and so on had predictive value for the occurrence of “crosstalk” effect. In this study, the “crosstalk” occurred in 33 cases (94.3%) of left pulmonary vein and 2 cases (5.7%) of right pulmonary vein. The significant difference in the proportion of “crosstalk” effect between the left and right sides is also determined by the anatomical characteristics of the pulmonary vein. Chun et al. analyzed and studied the relationship between the anatomical characteristics of pulmonary vein and “crosstalk” effect in early period. Ten patients isolated the superior pulmonary vein by “crosstalk” effect, all of which occurred on the left side. The distance between the RSPV and the inferior pulmonary vein is generally longer than that of the left pulmonary vein, and the shape of the right inferior pulmonary vein is obviously backward leading to the probability of interaction during the operation is small. The anatomical characteristics of short distance between the superior and inferior pulmonary vein will make the cryoballoon cover the ipsilateral adjacent pulmonary vein in varying degrees, resulting in prior freezing injury and subsequent “crosstalk” effect.
| Conclusion|| |
The “crosstalk” technique is not only a rapid method to complete PVI, but also a method to reduce the risk of cryoballoon ablation. The full understanding of the shape, characteristics, and variation of the pulmonary vein through the three-dimensional image of the left atrium-pulmonary vein before operation will be helpful for the operator to use the “crosstalk” technique to complete the operation safely and effectively.
Financial support and sponsorship
This study was supported by the National Natural Science Foundation of China (No. 81670309).
Conflicts of interest
There are no conflicts of interest.
Institutional review board statement
The study was approved by the Ethics Committee of Fuwai Hospital, China.
Declaration of patient consent
The authors certify that they have obtained all appropriate consent from patients. In the forms the patients have given their consent for their images and other clinical information to be reported in the journal. The patients understand that their names and initials will not be published and due efforts will be made to conceal their identity forms.
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[Figure 1], [Figure 2], [Figure 3]
[Table 1], [Table 2]