Collateral Nervous Damages After Cryoballoon Pulmonary Vein Isolation

Esophageal temperature management during cryoballoon ablation for atrial fibrillation

INTRODUCTION

Esophageal thermal injury (ETI) is a well-recognized complication of atrial fibrillation (AF) ablation. Previous studies have demonstrated that direct esophageal cooling reduces ETI during radiofrequency AF ablation. The purpose of this study was to evaluate the use of an esophageal warming device to prevent ETI during cryoballoon ablation (CBA) for AF.

METHODS

This prospective, double-blinded study enrolled 42 patients with symptomatic AF undergoing CBA. Patients were randomized to the treatment group with esophageal warming (42°C) using recirculated water through a multilumen, silicone tube inserted into the esophagus (EnsoETM®; Attune Medical) (WRM) or the control group with a luminal single-electrode esophageal temperature monitoring probe (LET). Patients underwent upper endoscopy esophagogastroduodenoscopy (EGD) the following day. ETI was classified into four grades.

RESULTS

Baseline patient characteristics were similar between groups. Procedural characteristics including number of freezes, total freeze time, early freeze terminations, coldest balloon temperature, procedure duration, posterior wall ablation, and proton pump inhibitor and transesophageal echocardiogram use before procedure were not different between groups. The EGD was completed in 40/42 patients. There was significantly more ETI in the WRM group compared to the LET group (n = 8 [38%] vs. n = 1 [5%], p = 0.02). All ETI lesions were grade 1 (erythema) or 2 (superficial ulceration). Total freeze time in the left inferior pulmonary vein was predictive of ETI (360 vs. 300 s, p = 0.03).

CONCLUSION

Use of a luminal heat exchange tube for esophageal warming during CBA for AF was paradoxically associated with a higher risk of ETI.

Gastric distension and gastroparesis following pulmonary vein isolation for atrial fibrillation: a case report and review of the literature

We present a case of marked gastric distension and gastroparesis in a patient with atrial fibrillation who underwent a pulmonary vein isolation, a procedure commonly performed in patients suffering from atrial fibrillation in order to regain sinus rhythm. Two days following the procedure, the patient presented with marked abdominal distension, and computed tomography imaging was consistent with gastroparesis and/or delayed gastric emptying. A tentative diagnosis of pylorospasm was made. After a first attempt with a conservative approach, gastroscopy with both pyloric dilatation and intra-pyloric botox injection was performed due to persisting discomfort. The symptoms gradually resolved following this intervention. Gastroparesis and gastrointestinal distension is a rare complication following pulmonary vein isolation, and is mainly thought to result from temporary damaging the vagal nerve. Since a rising number of patients undergo an ablation of the pulmonary veins as treatment for atrial fibrillation, gastroenterologists should become aware of this probably not so rare complication.

Heart rate increase and inappropriate sinus tachycardia after cryoballoon pulmonary vein isolation for atrial fibrillation

BACKGROUND

Cryoballoon pulmonary vein isolation (PVI) is a common therapy for atrial fibrillation (AF). While moderately increased sinus rhythm heart rate (HR) after PVI has been observed, inappropriate sinus tachycardia (IST) is a rare phenomenon. We aimed to investigate the prevalence and natural history of an abnormal sinus HR response after cryoballoon PVI.

METHODS

We included 169/646 (26.2%) patients with AF undergoing PVI with available Holter recordings before and 3, 6 and 12 months after the procedure. Patients with AF on Holter monitoring were excluded. Mean HR increase ≥ 20 bpm or an IST-like pattern (mean HR > 90 bpm or > 80 bpm when beta-blocking agents were used) following PVI was categorised as abnormal sinus HR response.

RESULTS

Following PVI, mean HR ± standard deviation increased in the entire group from 63.5 ± 8.4 to 69.1 ± 9.9 bpm at 3 months (p < 0.001), and to 71.9 ± 9.4 bpm at 6 months (p < 0.001). At 12 months, mean HR was 71.2 ± 10.1 bpm (p < 0.001). Only 7/169 patients (4.1%) met criteria for abnormal sinus HR response: mean HR was 61.9 ± 10.6 bpm (pre-ablation), 84.6 ± 9.8 bpm (3 months), 80.1 ± 6.5 bpm (6 months) and 76.3 ± 10.1 bpm (12 months). Even at 12 months, mean HR was significantly different from that pre-ablation in this group (p = 0.033). However, in patients meeting IST-like pattern criteria, mean HR at 12 months was no longer significantly different from that pre-ablation.

CONCLUSION

Few patients had an abnormal sinus HR response after PVI. Peak HR was observed 3 months after PVI, but HR was still significantly increased 12 months post-ablation compared with pre-ablation. An IST-like pattern was rarely observed. In these patients, HR decreased to pre-ablation values within a year.

Distance between the descending aorta and the left inferior pulmonary vein as a determinant of biophysical parameters during paroxysmal atrial fibrillation cryoablation

INTRODUCTION

The distance from the descending aorta (DA) to the posterior wall of the left atrium (LA) is variable. We aimed to determine whether the proximity between the DA and the left inferior pulmonary vein (LIPV) ostium has an impact on biophysical parameters and cryoballoon (CB) ablation efficacy during LIPV freezing.

METHODS

Patients referred for CB-ablation of atrial fibrillation (AF) in two high-volume centers were included. Cryoablation data were collected prospectively for each patient. The anatomical relationships between the LIPV and the DA (distance LIPV ostium-DA, presence of an aortic imprint on the posterior aspect of the LIPV) were then retrospectively analysed on the LA computed tomography scans realized before AF ablation.

RESULTS

A total of 350 patients were included (70% men, 59.7 ± 11.5 years). The decrease in the Ostium-DA distance was significantly correlated to the increase in the time-to-isolation (TTI) (r = -.31; p = .036), with less negative temperature (r = -.11; p = .045). Similarly, the presence of an aortic imprint on the LIPV was associated with a longer TTI (p < .001). The analysis of redo procedures data shows a trend toward the presence of shorter ostium-DA distances (15.3 ± 3.29 vs. 18.1 ± 4.99, p = .15) and more frequent aortic imprints (63.6% vs. 47.5%, p = .34) in patients with LIPV reconnection as opposed to patients without reconnection in the LIPV.

CONCLUSION

Our findings indicated that the DA seems to have a "radiator" effect influencing LIPV cryoablation parameters during CB-ablation. Additional studies will be needed to elucidate whether this biophysical influence has a clinical impact in LIPVs reconnections.

Comparison between superior vena cava ablation in addition to pulmonary vein isolation and standard pulmonary vein isolation in patients with paroxysmal atrial fibrillation with the cryoballoon technique

Background

Paroxysmal atrial fibrillation (PAF) can be triggered by non-pulmonary vein foci, like the superior vena cava (SVC). The latter is correlated with improved result in terms of freedom from atrial tachycardias (ATs), when electrical isolation of this vessel utilizing radiofrequency energy (RF) is achieved.

Objectives

Evaluate the clinical impact, in patients with PAF, of the SVC isolation (SVCi) in addition to ordinary pulmonary vein isolation (PVI) by means of the second-generation cryoballoon (CB)

Methods

A total of 100 consecutive patients that underwent CB ablation for PAF were retrospectively selected. Fifty consecutive patients received PVI followed by SVCi by CB application, and the following 50 consecutive patients received standard PVI. All patients were followed 12 months.

Results

The mean time to SVCi was 36.7 ± 29.0 s and temperature at SVC isolation was − 35 (− 18 to − 40) °C. Real-time recording (RTR) during SVCi was observed in 42 (84.0%) patients. At the end of 12 months of follow-up, freedom from ATs was achieved in 36 (72%) patients in the PVI only group and in 45 (90%) patients of the SVC and PV isolation group (Fisher’s exact test p = 0.039, binary logistic regression: p = 0.027, OR = 0.28, 95%CI = 0.09–0.86). In survival analysis, SVC and PV isolation group was also associated with improved freedom from ATs (log-rank test: p = 0.017, Cox regression: p = 0.026, HR = 0.31, 95%CI = 0.11–0.87).

Conclusion

Superior vena cava isolation with the CB in addition to PVI might improve freedom from ATs if compared to PVI alone at 1-year follow-up.

High incidence of (ultra)low oesophageal temperatures during cryoballoon pulmonary vein isolation for atrial fibrillation

Background

Low oesophageal temperatures (OTs) during cryoballoon pulmonary vein isolation (PVI) have been associated with complications. This study assessed the incidence of low OT in clinical practice during cryoballoon PVI and verified possible predictive values for low OT.

Methods

Consecutive patients who underwent PVI using the second-generation cryoballoon were retrospectively included. The distance from the oesophagus to the different pulmonary veins (PVs) (OP distance), body mass index (BMI), sex, age, balloon temperature and application time were studied as potential predictors of low OTs. Computed tomography was performed before the procedure to determine the OP distance. OT was measured using an oesophageal temperature probe. Applications were ended prematurely if the OT reached <16 °C. Low and ultralow OT were defined as OT <20 and <16 °C respectively.

Results

Two hundred and four patients were included. Low OT was observed in 54 patients (26%) and 27 patients (13%) reached ultralow OTs. OP distance was the only predictor of low OTs after multivariate analysis. A cut-off value of 19 mm showed 96.2% sensitivity and 37.8% specificity in predicting low OTs. No clinically relevant relation was found between low OTs and BMI, age, sex, balloon temperature or application duration.

Conclusions

The incidence of low OT was 26% for cryoballoon PVI. OP distance was the only predictor of low OTs. Since an OP distance <19 mm was present in all patients in at least one PV, we recommend routine OT measurement during PVI cryoballoon therapy to prevent oesophagus-related complications.

Catheter Ablation in the Treatment of Atrial Fibrillation

Catheter ablation (CA) of the pulmonary veins for atrial fibrillation (AF) is growing exponentially and is the most commonly performed electrophysiologic procedure. Initial descriptions focused on CA for paroxysmal AF, and now more recently expanded in application to persistent AF and those with comorbid heart failure. Efforts to improve success have and continue to address issues such as pulmonary vein "reconnection" following ablation through different ablative energy modalities, and the use of a "hybrid" surgical/endocardial combined approach in persistent forms of AF. Technologic advances as well are concurrently seeking to improve safety, particularly regarding the incidence of atrio-esophageal fistula in this seemingly ever-growing ablation population.

Determination of the effects of cryoablation for atrial fibrillation on esophageal functions

Objective:

Periesophageal vagal plexus injury is a complication of cryoablation for atrial fibrillation (AF). The aim of this study is to investigate the effect of cryoablation on esophageal functions and to determine the relationship between esophageal temperature and esophageal motility.

Methods:

Twenty patients with symptomatic paroxysmal AF who underwent cryoablation were included in this study. The lowest cryoballoon temperature for each pulmonary vein (PV) was recorded. Esophageal temperature was measured using an esophageal probe during each cryoapplication. Esophageal manometry was performed before the procedure and one day after the procedure for each patient in order to assess the esophageal functions.

Results:

During the procedure, the highest esophageal temperature change was found in the left-side PVs in 13 patients (65%) and in the right-side PVs in seven patients (35%). No correlation was found between the lowest cryoballoon temperature and esophageal temperature change (r=0.22, p=0.05). It was detected that the lower esophageal sphincter pressure and esophageal contraction amplitude pressure decreased after the procedure (before: 19.7±9.3 mm Hg, after: 14.3±4.9 mm Hg, p=0.001; before: 84.5±28.3 mm Hg, after: 72.7±34.3 mm Hg, p=0.005, respectively). Five patients (25%) developed gastrointestinal symptoms after the procedure.

Conclusion:

During cryoablation, esophageal temperature measurement can be performed to reduce the probability of esophageal injury. Cryoablation affects esophageal motility, and esophageal manometry can be performed to detect esophageal motility impairments in patients with gastrointestinal symptoms.

Phrenic nerve palsy during right-sided pulmonary veins cryoapplications: new insights from pulmonary vein anatomy addressed by computed tomography

PURPOSE

There is still sparse information regarding phrenic nerve palsy (PNP) during the cryoablation of both right-sided pulmonary vein (PV) and its anatomical predictors.

METHODS

Consecutive patients who had undergone pulmonary vein isolation (PVI) using CB-A and suffered PNP during both right-sided PVs were retrospectively included in our study. Two other groups were then selected among patients who experienced PNP during RIPV application only (group 2) and RSPV application only (group 3).

RESULTS

The incidence of PNI during both right-sided PVs cryoapplications was 2.1%, (32 of 1542 patients). There were no significant clinical differences between the 3 groups. Time from basal temperature to -40 °C significantly differed among the groups for both RIPV (p = 0.0026) and RSPV applications (p = 0.0382). Patients with PNP occurring during RSPV applications had significantly larger RSPV cross-sectional area compared to patients without PNP (p = 0.0116), while in patients with PNP during RIPV application, the angle of RIPV ostium on the transverse plane was significantly smaller compared to patients without PNP (p = 0.0035). The carina width was significantly smaller in patients with PNP occurring during both right-sided PVs cryoapplications compared to patients in which PNP occurred only during one right-sided PV application (p < 0.0001); a cutoff value of 8.5 mm had a sensitivity of 87.3% and a specificity of 75.0%.

CONCLUSION

PNP in both right-sided PVs applications is a complication that occurred in 2.1% of cases during CB-A. Pre-procedural evaluation of right PVs anatomy might be useful in evaluating the risk of PNP.

Acute Procedural Complications of Cryoballoon Ablation: A Comprehensive Review

Catheter ablation is increasingly performed for treatment of atrial fibrillation (AF). Balloon based procedures have been developed aiming at safer, easier and more effective treatment as compared to point to point ablation. In the present review article, we aimed to discuss acute procedural complications of cryoballoon ablation.

Optimizing ablation duration using dormant conduction to reveal incomplete isolation with the second generation cryoballoon: A randomized controlled trial

Introduction

Efficacy of cryoballoon ablation depends on balloon‐tissue contact and ablation duration. Prolonged duration may increase extracardiac complications. The aim of this study is to determine the optimal additional ablation duration after acute pulmonary vein isolation (PVI).

Methods

Consecutive patients with paroxysmal AF were randomized to three groups according to additional ablation duration (90, 120, or 150 seconds) after acute PVI (time‐to‐isolation). Primary outcome was reconnection/dormant conduction (DC) after a 30 minutes waiting period. If present, additional 240 seconds ablations were performed. Ablations without time‐to‐isolation <90 seconds, esophageal temperature <18°C or decreased phrenic nerve capture were aborted. Patients were followed with 24‐hour Holter monitoring at 3, 6, and 12 months.

Results

Seventy‐five study patients (60 ± 11 years, 48 male) were included. Reconnection/DC per vein significantly decreased (22%, 6% and 4%) while aborted ablations remained stable (respectively 4, 5, and 7%) among the 90, 120, and 150 seconds groups. A shorter cryo‐application time, longer time‐to‐isolation, higher balloon temperature and unsuccessful ablations predicted reconnection/DC. Freedom of atrial fibrillation was, respectively, 52, 56, and 72% in 90, 120, and 150 seconds groups ( P = 0.27), while repeated procedures significantly decreased from 36% to 4% ( P = 0.041) in the longer duration group compared to shorter duration group (150 seconds vs 90 seconds group). In multivariate Cox‐regression only reconnection/DC predicted recurrence.

Conclusion

Prolonging ablation duration after time‐to‐isolation significantly decreased reconnection/DC and repeated procedures, while recurrences and complications rates were similar. In a time‐to‐isolation approach, an additional ablation of 150 seconds ablation is the most appropriate.

Complications of Cryoballoon Pulmonary Vein Isolation

Since the cryoballoon (CB) was introduced into clinical practice, more than 400,000 patients have undergone a pulmonary vein (PV) isolation with a CB throughout the world. Although the efficacy of the first-generation CB was limited, the recently introduced second-generation CB has achieved a greater uniformity in cooling, which has facilitated a shorter time to PV isolation, shorter procedural times, higher rates of freedom from atrial fibrillation and low rates of PV reconnections. Currently, a single short freeze strategy with a single 28 mm balloon has become the standard technique based on the balance of procedural efficacy and safety. However, enhanced cooling characteristics may also result in a greater potential for collateral damage to non-cardiac structures. Knowledge about the potential complications is essential when performing the procedure. In this article, we describe the important complications that should be noted during a CB procedure, and how to minimise the risk of complications based on our experience.

Shorter cryoballoon applications times do effect efficacy but result in less phrenic nerve injury: Results of the randomized 123 study

Background

The second‐generation cryoballoon significantly improves outcome of pulmonary vein isolation (PVI) but may cause more complications than the first generation. Currently, no consensus regarding optimal cryoballoon application time exists. The 123‐study aimed to assess the minimal cryoballoon application duration necessary to achieve PVI (primary endpoint) and the effect of application duration on prevention of phrenic nerve injury (PNI).

Methods

Patients <75 years of age with paroxysmal atrial fibrillation, normal PV anatomy, and left atrial size <40 cc/m² or <50 mm were randomized to two applications of different duration: “short,” “medium,” or “long.” A total of 222 patients were enrolled, 74 per group.

Results

Duration per application was 105 (101‐108), 164 (160‐168), and 224 (219‐226) s and isolation was achieved in 79, 89, and 90% (P < 0.001) of the PVs after two applications in groups short, medium, and long, respectively. Only for the left PVs, the success rate of the short group was significantly less compared to the medium‐ and long‐duration groups (P < 0.001). PNI during the procedure occurred in 19 PVs (6.5%) in the medium and in 20 PVs (6.8%) in the long duration groups compared to only five PVs (1.7%) in the short duration group (P < 0.001).

Conclusions

Short cryoballoon ablation application times, less than 2 min, did affect the success for the left PVs but not for the right PVs and resulted in less PNI. A PV tailored approach with shorter application times for the right PVs might be advocated.

The Impact of Advances in Atrial Fibrillation Ablation Devices on the Incidence and Prevention of Complications

The number of patients with atrial fibrillation currently referred for catheter ablation is increasing. However, the number of trained operators and the capacity of many electrophysiology labs are limited. Accordingly, a steeper learning curve and technical advances for efficient and safe ablation are desirable. During the last decades several catheter-based ablation devices have been developed and adapted to improve not only lesion durability, but also safety profiles, to shorten procedure time and to reduce radiation exposure. The goal of this review is to summarise the reported incidence of complications, considering device-related specific aspects for point-by-point, multi-electrode and balloon-based devices for pulmonary vein isolation. Recent technical and procedural developments aimed at reducing procedural risks and complications rates will be reviewed. In addition, the impact of technical advances on procedural outcome, procedural length and radiation exposure will be discussed.

How to Prevent, Detect and Manage Complications Caused by Cryoballoon Ablation of Atrial Fibrillation

Atrial fibrillation is the most common cardiac arrhythmia and the prevalence is increasing every year. Patients who fail to maintain sinus rhythm with use of anti-arrhythmic drug therapy are referred for catheter ablation. Cryoballoon (CB) ablation has emerged as an effective and alternative treatment option to traditional point-by-point radiofrequency ablation, but there can be complications. This article reviews the incidence, presentation, risk factors, management and preventative strategies of three major complications associated with CB ablation: phrenic nerve injury, atrial oesophageal fistula and bronchial injury. Although these complications are rare, electrophysiologists should institute measures to identify high-risk patients, implement best-practice techniques to minimise risks and maintain a high index of suspicion to recognise the complications quickly and implement correct treatment strategies.

Complications of Atrial Fibrillation Cryoablation

Catheter ablation either by using radiofrequency or cryo energy in symptomatic patients with atrial fibrillation (AF) has shown to be effective as compared to anti-arrhythmic drugs. However, all the techniques used during AF ablation are not free of complication. There are several well-known peri-procedural complications in which operators should be informed of the possible risks, cautious during the procedure and able to manage them when occurred. Herein, we aimed to review possible complications of AF cryoablation.

How to prevent, recognize and manage complications of AF ablation?

Ablation of atrial fibrillation (AF) is one of most complex procedures in electrophysiology. Many technical improvements have been incorporated lately in order to improve clinical results and reducing risks. Currently, cardiac tamponade, stroke, PV stenosis, phrenic palsy and atrial esophageal fistula are still recognized as the major risks of AF ablation, although their managements have been much better established. The aim of this article is to review recent data in how to avoid, to identify and to treat such complications.

Gastrointestinal complications associated with catheter ablation for atrial fibrillation

Atrial fibrillation is the most common arrhythmia in the United States. With the ageing population, the incidence and prevalence of atrial fibrillation are on the rise. Catheter ablation of atrial fibrillation is a widely accepted treatment modality in patients with drug refractory symptomatic paroxysmal or persistent atrial fibrillation. The close proximity to the left atrium posterior wall makes the thermosensitive esophagus a potential site of injury during catheter ablation of AF leading to various gastrointestinal complications. The major gastrointestinal complications associated with catheter ablation include atrioesophageal fistula, gastroparesis, esophageal thermal lesions and esophageal ulcers. Multiple studies, case reports and series have described these complications with various catheter ablation techniques such as radiofrequency, cryoenergy and high frequency focused ultrasound energy ablation. This review addresses the gastrointestinal complications after AF ablation procedures and aims to provide the clinicians with an overview of clinical presentation, etiology, pathogenesis, prevention and management of these conditions.

Periesophageal vagal plexus injury is a favorable outcome predictor after catheter ablation of atrial fibrillation

BACKGROUND

Collateral damage to periesophageal vagal plexus associated with symptomatic gastric hypomotility and associated symptoms are not uncommon after catheter ablation of atrial fibrillation (AF). The injury may indicate transmural ablation lesions.

OBJECTIVE

The purpose of this study was to evaluate the periesophageal vagal plexus injury (PNI) and long-term outcome after catheter ablation of AF.

METHODS

A total of 441 consecutive patients with AF (mean age 54.71 ± 10.52 years; 134 women) who underwent catheter ablation (paroxysmal AF, n = 312; persistent AF, n = 129) were retrospectively enrolled from 2011 to 2013; group 1 was defined as patients with PNI and associated symptoms (n = 88), and group 2 was defined as patients without PNI or associated symptoms (n = 353). Baseline characteristics and electrophysiological properties were collected to analyze the relationship between PNI and clinical outcome. The association of AF recurrence after catheter ablation and PNI symptoms was also investigated.

RESULTS

During a mean follow-up period of 37.3 ± 0.94 months, group 1 had longer AF-freedom days in sinus rhythm after AF ablation and had less recurrence after the blanking period compared with group 2 (mean recurrence days, 1254.22 ± 45.26 days vs 1065.21 ± 33.35 days; P < .01). Multivariate analysis also revealed that PNI was an independently protective predictor of AF recurrence (hazard ratio 0.527; 95% confidence interval 0.289-0.959; P = .036). There was no difference in baseline characteristics, CHA2DS2-VASc score, or echocardiography follow-up duration.

CONCLUSION

PNI and associated symptoms are not uncommon after catheter ablation of AF. A better long-term outcome is thereby independently predicted, suggesting transmural ablation lesions during pulmonary vein isolation.

ECG-Guided Surveillance Technique in Cryoballoon Ablation for Paroxysmal and Persistent Atrial Fibrillation: A Strategy to Prevent From Phrenic Nerve Palsy

AIMS

Phrenic nerve palsy (PNP) is still a cause for concern in Cryoballoon ablation (CBA) procedures. New surveillance techniques, such as invasive registration of the compound motor action potential (CMAP), have been thought to prevent the occurrence of PNP. The present study investigates the impact of CMAP surveillance via an alternative and non-invasive ECG-conduction technique during CBA.

METHODS

PVI with CBA was performed in 166 patients suffering from AF. Diaphragmal contraction was monitored by abdominal hands-on observation in Observation Group I; Observation Group II was treated using additional ECG-conduction, as a means of modified CMAP surveillance method. During the ablation of the right superior and inferior pulmonary veins, the upper extremities lead I was newly adjusted between the inferior sternum and the right chest, thereby recording the maximum CMAP. The CMAP in the above-mentioned ECG leads was continuously observed in a semi-quantitative manner.

RESULTS

PNP was observed in 10 (6%) patients in total. In Observation Group I, 6 out of 61 (9.8%) demonstrated PNP. In Observation Group II a significant decrease of PNP could be demonstrated (p <0,001) and occurred in 4 out of 105 patients (3.8%). While three patients from Observation Group I left the EP lap with an ongoing PNP, none of the patients in Observation Group II had persistent PNP outside of the EP lab.

CONCLUSION

The present study demonstrates that additional ECG-conduction, used as modified CMAP surveillance, is an easy, effective and helpful additional safety measure to prevent PNP in CBA.

Innappropriate Sinus Tachycardia After Superior Vena Cava Isolation In Addition To Pulmonary Veins Isolatin Of Paroxysmal Atrial Fibrillation Cryoballoon Ablation

We report a case of persistent inappropriate sinus tachycardia (IST) after pulmonary vein and superior vena cava (SVC) isolation with cryoballoon ablation for paroxysmal atrial fibrillation (PAF). After the cryoballoon ablation (CBA) procedure, the patient presented with sinus tachycardia of 105 beats/minute. The patient was successfully treated with metoprolol and ivabradine therapy.

Epidemiology and definition of inappropriate sinus tachycardia

Inappropriate sinus tachycardia (IST) is a clinical syndrome lacking formal diagnostic criteria. It is generally defined as an elevated resting heart rate (HR; >90-100 bpm) with an exaggerated response to physical or emotional stress and a clearly sinus mechanism. Clinical manifestations are broad from a complete lack of symptoms to incapacitating incessant tachycardia. Now understood to be relatively prevalent, it is observed to have a generally benign prognosis, though symptoms may persist for years. Whether IST is a single discrete entity or a heterogeneous condition with overlap to other syndromes such as postural orthostatic tachycardia syndrome remains a matter of debate.

MRI Reconstructions of Human Phrenic Nerve Anatomy and Computational Modeling of Cryoballoon Ablative Therapy

The primary goal of this computational modeling study was to better quantify the relative distance of the phrenic nerves to areas where cryoballoon ablations may be applied within the left atria. Phrenic nerve injury can be a significant complication of applied ablative therapies for treatment of drug refractory atrial fibrillation. To date, published reports suggest that such injuries may occur more frequently in cryoballoon ablations than in radiofrequency therapies. Ten human heart-lung blocs were prepared in an end-diastolic state, scanned with MRI, and analyzed using Mimics software as a means to make anatomical measurements. Next, generated computer models of ArticFront cryoballoons (23, 28 mm) were mated with reconstructed pulmonary vein ostias to determine relative distances between the phrenic nerves and projected balloon placements, simulating pulmonary vein isolation. The effects of deep seating balloons were also investigated. Interestingly, the relative anatomical differences in placement of 23 and 28 mm cryoballoons were quite small, e.g., the determined difference between mid spline distance to the phrenic nerves between the two cryoballoon sizes was only 1.7 ± 1.2 mm. Furthermore, the right phrenic nerves were commonly closer to the pulmonary veins than the left, and surprisingly tips of balloons were further from the nerves, yet balloon size choice did not significantly alter calculated distance to the nerves. Such computational modeling is considered as a useful tool for both clinicians and device designers to better understand these associated anatomies that, in turn, may lead to optimization of therapeutic treatments.

Gastroparesis as a Complication of Atrial Fibrillation Ablation

Percutaneous catheter ablation is a safe and effective treatment for symptomatic drug-resistant atrial fibrillation (AF). Gastroparesis is a little known complication of AF ablation. We aimed to evaluate the frequency of gastroparesis in the patients who underwent catheter ablation for AF by cryoballoon (CB) or radiofrequency (RF) and to define risk factors for gastroparesis. In all, 104 patients were treated with pulmonary vein (PV) isolation with 2 different technologies: CB in 58 patients (group 1) and open-irrigated tip RF catheter in 46 patients (group 2). Gastroparesis was seen in 7 cases (6 cases in group 1 and 1 case in group 2, respectively). The complaints related with gastroparesis began during the procedure in 4 of 6 patients of group 1. The other 3 patients admitted to our outpatient clinic with similar complaints within 72 to 96 hours after the procedure. For gastroparesis cases of group 1, mean minimal CB temperature on inferior PVs was lower and left atrium diameter was smaller. Management was conservative, and the patients have no residual symptoms at 6-month follow-up. The only patient still demonstrating residual symptoms during follow-up was in group 2. Although, clinically manifest gastroparesis is quite common with CB ablation, the process is generally reversible. However, damage may not be as reversible with RF ablation. In conclusion, during cryoablation, lower temperatures on inferior PVs and small left atrium size may be associated with increased risk of gastroparesis, and fluoroscopic guidance may be useful to avoid this complication.

Factors associated with periesophageal vagal nerve injury after pulmonary vein antrum isolation

Background

Periesophageal vagal nerve injury is recognized as a rare complication in atrial fibrillation ablation procedures. We investigated the factors associated with the occurrence of symptomatic periesophageal vagal nerve injury after pulmonary vein antrum isolation.

Methods and Results

Overall, 535 consecutive patients who underwent sole pulmonary vein antrum isolation were included. Point‐by‐point radiofrequency applications were applied using irrigated‐tip catheters under minimal sedation without esophageal temperature monitoring. In the initial 165 patients, the ablation settings for the posterior left atrium were a maximum energy of 25 to 30 W and a duration of 30 seconds. In the subsequent 370 patients, the power was additionally limited to 20 to 25 W at specific parts of the posterior left atrium where the ablation line transversed the esophagus. Symptomatic gastric hypomotility was found in 13 patients, and all were observed during the initial period (7.9%). No other collateral damage was observed. Logistic regression analysis revealed that the body mass index was the only independent predictor for identifying patients with gastric hypomotility (odds ratio 0.770; 95% confidence interval 0.643 to 0.922; P=0.0045) during the initial period. The prevalence of gastric hypomotility was significantly higher in the initial study period than subsequently (0 of 370, 0%; P<0.0001). All except for 1 patient recovered completely with conservative treatment within 4 months after the procedure.

Conclusions

Periesophageal vagal nerve injury is more common collateral damage than direct esophageal injury in pulmonary vein antrum isolation procedures. Titrating the radiofrequency energy at specific areas where the ablation line transverses the esophagus and taking account of the body mass index might reduce occurrences not only of direct esophageal damage but also of periesophageal vagal nerve injury in pulmonary vein antrum isolation procedures.

Major complications of cryoballoon catheter ablation for atrial fibrillation and their management

Atrial fibrillation (AF) is the most common symptomatic and sustained cardiac arrhythmia. It affects approximately 2-3 million people in the USA alone with an increased incidence and prevalence worldwide. It is associated, in addition to worsening quality of life, with increased morbidity and mortality especially in poorly controlled AF, affecting mostly those older than 65 years of age. Radiofrequency ablation was found to be a good strategy for focal isolation of pulmonary veins triggering from the vulnerable atrial substrate but is a time-consuming procedure and carries the risk of multiple complications like tamponade which could be fatal, atrioesophageal fistula and local thrombus formation at the site of ablation. Cryoballoon ablation with pulmonary vein isolation has emerged in the past few years as a breakthrough novel technology for the treatment of drug-refractory AF. It is a relatively simple alternative for point-by-point radiofrequency ablation of paroxysmal AF and is associated with fewer incidences of fatal complications such as cardiac perforation. As experience with this new tool accumulates, the field faces new challenges in the form of rare compilations including gastroparesis, phrenic nerve palsy, atrioesophageal fistula, pulmonary vein stenosis, thromboembolism pericardial effusion, and tamponade.

Complications of circumferential pulmonary vein isolation using the cryoballoon technique: Incidence and predictors

BACKGROUND

Cryoballoon ablation technique for the treatment of atrial fibrillation (AF) is a complex procedure consisting of several procedural steps associated with significant risk of complications. The aim of this single-centre study was to give detailed analysis of the complication rate and corresponding risk factors of pulmonary veins cryoisolation (PVI) procedures.

METHODS AND RESULTS

A total of 158 consecutive patients (71.5% men, aged 57 ± 9 years, 73.3% paroxysmal atrial fibrillation) were enrolled. Out of 632 pulmonary veins, 96.7% were targeted and isolated by 2-7 applications of cryothermal energy guided with intracardiac echocardiography and fluoroscopy. The additional ablation of cavotricuspid isthmus was performed in 14.6% of procedures. In total, 29 complications were recorded in peri-procedural or early post-procedural period, 8 (5.1%) of them being evaluated as major. No case of permanent injury, disability or death was registered. Multivariate logistic regression showed the persistence of pre-ablation AF as the risk factor of major complications (OR=5.0; ± 95% CI: 1.14-21.97, P=0.033); lower body height was the significant risk factor of any complications (OR=0.95; ± 95% CI: 0.91-0.99, P=0.026) with rapid increase of complication risk with body height ≤ 162 cm. Embolic complications were significantly associated with the pre-ablation AF, while patients with low body height had a trend towards increased risk of phrenic nerve palsy.

CONCLUSION

Our study confirmed that the cryoballoon pulmonary vein isolation can be safely performed with low incidence of life-threatening complications which may be further decreased if the mentioned risk factors are handled appropriately.