Immediate balloon deflation for prevention of persistent phrenic nerve palsy during pulmonary vein isolation by balloon cryoablation

Single 3-min freeze per vein ablation strategy with the second-generation cryoballoon for atrial fibrillation in a large cohort of patients: long term outcome after a single procedure

PURPOSE

The purpose of the present study was to assess the long-term success rate of a single 3-min freeze per vein ablation strategy in the setting of pulmonary vein isolation (PVI) by means of second-generation cryoballoon (CB-A; Arctic Front Advance, Medtronic, Minneapolis, MN, USA) in a large cohort of patients.

METHODS

Three hundred and one patients with drug resistant atrial fibrillation (AF) having undergone PVI by means of CB-A using a single 3-min freeze per vein ablation strategy were included in the analysis.

RESULTS

Paroxysmal AF (PAF) was documented in 70.8% of the patients, while 29.2% presented with persistent AF (PersAF). The mean number of CB applications was 1.09 ± 0.3 in the left superior pulmonary vein (LSPV), 1.04 ± 0.2 in the left inferior pulmonary vein (LIPV), 1.12 ± 0.3 in the right superior pulmonary vein (RSPV), and 1.12 ± 0.3 in the right inferior pulmonary vein (RIPV). All PVs were successfully isolated with a 28-mm CB-A only. After a mean follow-up of 38.1 ± 7.5 months, 207 (68.8%) patients were free of atrial tachyarrhythmia (ATa) recurrences following a single procedure. Specifically, 72.8% of patients presenting with PAF and 59.1% of individuals with PersAF did not experience a recurrence.

CONCLUSIONS

A single 3-min freeze per vein strategy is effective in treating AF on a long term follow-up of 38 months. Specifically, it can afford freedom from ATa recurrences in 72.8% of patients affected by PAF and 59.1% of patients initially presenting with PersAF after a single CB-A procedure.

Characteristics of Phrenic Nerve Injury During Pulmonary Vein Isolation Using a 28-mm Second-Generation Cryoballoon and Short Freeze Strategy

BACKGROUND

The reported incidence of phrenic nerve injury (PNI) varies owing to different definitions, balloon generations, balloon size, freezing regimen, and protective maneuvers. We evaluated the incidence, predictors, and outcome of PNI during cryoballoon pulmonary vein isolation in a large population.

METHODS AND RESULTS

Five hundred fifty atrial fibrillation patients underwent pulmonary vein isolation using one 28-mm second-generation cryoballoon and single 3-minute freeze strategy under diaphragmatic compound motor action potential (CMAP) monitoring. A total of 34 (6.2%) patients experienced PNI during the right superior and inferior pulmonary vein ablation in 30 and 4 patients, respectively. Applications were interrupted using double-stop techniques after 136 [104-158] second applications, and a pulmonary vein isolation was already achieved in all but one case. The baseline CMAP amplitude and timing of deflation (CMAPdef) were 0.75±0.30 and 0.17±0.17 mV, respectively. Persistent atrial fibrillation, larger right superior pulmonary vein ostia, and deeper balloon positions were associated with higher incidences of PNI. The CMAPdef predicted a PNI recovery delay, and the best cutoff value for predicting PNI recovery by the next day was 0.20 mV (sensitivity 57.1%, specificity 100%). Among 6 patients undergoing second procedures 8.5 (6.7-15.0) months later, the right superior pulmonary vein was durable in 3 with >120 second applications. Despite active balloon deflation, no significant pulmonary vein stenosis was observed in 15 right superior pulmonary veins evaluated 6 (5-9) months later. No patients had symptoms, and the PNI recovered 1 day and 1 month postprocedure in 21 and 4 patients, respectively.

CONCLUSIONS

PNI resulting from cryoballoon ablation was reversible. The double-stop technique is safe, and immediate active deflation following a CMAP decrease appears to be essential for faster PNI recovery.

Retrospective review of Arctic Front Advance Cryoballoon Ablation: a multicenter examination of second-generation cryoballoon (RADICOOL trial)

BACKGROUND

Pulmonary vein isolation (PVI) via catheter ablation is an approved therapy for patients with drug-refractory and symptomatic atrial fibrillation (AF). Furthermore, cryoballoon is now considered to be as effective as focal radiofrequency catheter ablation. This study examines the second-generation cryoballoon performance in a US multicenter review of real-world practices.

METHODS

By retrospective chart collections, the long-term efficacy and safety of the cryoballoon procedure were assessed in 15 US centers. All patients had a history of drug-refractory symptomatic paroxysmal AF and were treated with a cryoballoon PVI strategy at the index ablation.

RESULTS

Four hundred fifty-two patients were evaluated, and acute PVI was achieved in 99% of patients by cryoballoon catheter ablation. In 0.88% of patients (4/452), an additional focal ablation catheter was used to achieve acute PVI during the ablation procedure. Average procedure time was 128 (range 82 to 260) min, using an average of 17 (range 1 to 19) min of fluoroscopy. The most frequent adverse event was transient phrenic nerve injury (1.5%; 7/452 patients) which all resolved by the end of the procedure with no diaphragmatic dysfunction at discharge. There were no strokes, transient ischemic attacks, cardiac tamponade, atrioesophageal fistulas, or deaths during the study. At the 12-month efficacy endpoint, single-procedure success of freedom from atrial arrhythmia was 87% (393/452 patients).

CONCLUSIONS

This real-world examination of the US practice demonstrates that second-generation cryoballoon ablation by PVI strategy is safe and effective among patients with paroxysmal AF.

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.

Pulmonary vein isolation with real-time pulmonary vein potential recording using second-generation cryoballoon: Procedural and biophysical predictors of acute pulmonary vein reconnection

OBJECTIVE

The study sought to evaluate the procedural and biophysical factors related to acute pulmonary vein isolation (PVI) guided by real-time pulmonary vein (PV) potential recordings.

METHODS

A total of 180 consecutive patients with drug-resistant atrial fibrillation (AF) undergoing CB2 (second-generation version of cryoballoon) ablation were enrolled. Real-time monitoring of PV potentials was obtained using an inner lumen spiral mapping catheter.

RESULTS

Acute isolation was achieved in all PVs without touch-up ablation. Real-time assessment of PV disconnection was possible in 611 of 711 (85.9%) PVs. A total of 617 (86.8%) PVs were isolated during the initial freeze. Longer time cycle integration (TCI) (TTI * freeze cycle, TCI) (254.6 ± 112.8 seconds vs 74.1 ± 59.7 seconds, P < 0.001), time to isolation (TTI) (94.3 ± 34.0 seconds vs 46.3 ± 26.2 seconds, P < 0.001), higher nadir temperature (-45.5 ± 5.3°C vs -50.4 ± 5.5°C, P < 0.001), longer time to -40°C (77.3 ± 22.7 seconds vs 55.7 ± 23.2 seconds, P < 0.001), faster interval rewarming time at 0°C (9.4 ± 4.3 seconds vs 12.4 ± 4.9 seconds, P = 0.008), and total balloon rewarming time (38.1 ± 11.6 seconds vs 47.7 ± 14.0 seconds, P = 0.003) were observed in PVs with acute reconduction. TTI ≤ 65 seconds predicted absence of acute reconnection with 84.2% sensitivity and 75.7% specificity, whereas TCI ≤ 119 seconds presented 94.7% sensitivity and 80.2% specificity. At a mean follow-up of 4.7 ± 1.4 months, 82.2% of patients were free of AF. None of those with PV reconnections suffered from AF recurrences.

CONCLUSIONS

The ablation using CB2 is effective in achieving acute PVI. Real-time assessment of PVI could be achieved during CB application in 86% of PVs. The incidence of spontaneous PV reconnection is very low, observed in just 3% of isolated PVs. TTI ≤ 65 seconds and TCI ≤ 119 seconds predicted absence of acute PV reconnection. Although they may identify effective cryoapplications in the acute phase, their performance still needs to be verified in the long term.

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.

Left phrenic nerve injury during electrical isolation of left-sided pulmonary veins with the second-generation cryoballoon

BACKGROUND

Phrenic nerve (PN) palsy (PNP) is the most frequent complication of cryoballoon ablation (CBA) of atrial fibrillation (AF). The major complication of this technique seems to be right-sided PN injury (PNI) following ablation of the right pulmonary veins (PVs). We sought to assess the incidence and prognosis of left-sided PNI during CBA.

METHODS

CBA was performed in 448 patients with AF. During the ablation of the left-sided PVs, the PN was paced from the left subclavian vein with a pacing output just exceeding the threshold by 10 ∼ 20%. The right and left arm 12-lead electrocardiogram electrodes were positioned 5 cm above the xiphoid process and 16 cm along the left costal margin. The amplitude of the compound motor action potentials was recorded during the CBA.

RESULTS

Two thousand one hundred seventy-eight CBA applications were delivered in 1,094 left-sided PVs. PNI occurred in 29 patients (6.5%); the PN could be captured by an increasing pacing output in 21 patients (4.7%), and premature termination of the freezing was required to avoid PNP in eight patients (1.8%). The PN function recovered before discharge; however, it took 7 months for one patient to completely recovery from the PNP.

CONCLUSIONS

Left-sided PNP could be provoked during a left-sided CBA procedure. Assessment of the left PN during the CBA was necessary to prevent left-sided PNP.

Association of P wave duration index with atrial fibrillation recurrence after cryoballoon catheter ablation

AIM

We aimed to investigate the relationship between the recurrence of AF and P wave duration index (PWDI) in patients with nonvalvular PAF.

METHODS

We included 114 patients who underwent cryoballoon catheter ablation with the diagnosis of paroxysmal atrial fibrillation (PAF) (55 male, 59 female; mean age 55.5±10,9years). PWDI was calculated by dividing the Pwd by the PR interval in DII lead of 12‑lead ECG. Patients had regular follow-up visits with 12-lead ECG, medical history and clinical evaluation. 24h Holter ECG monitoring had been recorded at least 12months after ablation.

RESULTS

AF recurrence was detected in 24 patients after 1year. Patients were divided into two groups according to the AF recurrence. All parameters were compared between the two groups. Age, DM, HT frequency, ACEI-ARB use, CHA2DS2VASc and HAS-BLED score, HsCRP, LA diameter, LA volume, LA volume index, Pwd and PWDI were related to AF recurrence. In binary logistic regression analysis, PWDI (OR=1.143, p=0.001) and HT (OR=0.194, p=0.020) were found to be independent parameters for predicting AF recurrence. Every 0,01 unit increase in PWDI was found to be associated with 14.3% increase in the risk of AF recurrence. The cut-off value of PWDI obtained by ROC curve analysis was 59,9 for prediction of AF recurrence (sensitivity: 75.0%, specificity: 69.0%). The area under the curve (AUC) was 0.760 (p<0.001).

CONCLUSION

Increased PWDI may help to identify those patients in whom electrical remodeling has already occurred and who will get less benefit from cryoablation.

Single freeze strategy with the second- generation cryballoon for atrial fibrillation: a multicenter international retrospective analysis in a large cohort of patients

PURPOSE

The second-generation cryoballoon (CB-A, Arctic Front Advance, Medtronic, Minneapolis, MN, USA) has proven to be highly effective in achieving freedom from atrial fibrillation; nonetheless, the ideal number and duration of freezing cycles is still a matter of debate. We investigated the acute success, procedural complications, and clinical outcome of a single freeze strategy using the CB-A in a large, retrospective, international multicenter study.

METHODS

Between January 2013 and September 2015, 818 consecutive patients (58 ± 12 years, 68% males) with drug-resistant atrial fibrillation (AF) who underwent a CB-A using a single freeze strategy were taken into consideration for our analysis.

RESULTS

Paroxysmal AF was documented in 74.1% of the patients, while 25.9% presented with persistent AF. Additional freezes were needed in a mean 1.4 veins per patient. 0.2% of the patients experienced persistent PNP that was still documented at the last follow-up. After a median follow-up of 14 ± 8 months, taking into consideration a blanking period (BP) of 3 months, 692 patients (84.6%) were free from arrhythmia recurrence. After a single procedure, AF recurrence during BP and persistent AF were identified as predictors of clinical recurrence after BP.

CONCLUSIONS

Single freeze CB-A ablation is effective in treating drug-resistant AF and affords freedom from arrhythmia recurrences in 84.6% of patients during a 14-month follow-up. Persistent AF and recurrence during BP are predictors of arrhythmia recurrences.

Repeat procedures using the second-generation cryoballoon for recurrence of atrial fibrillation after initial ablation with conventional radiofrequency

PURPOSE

Pulmonary vein isolation is now widely accepted for the treatment of symptomatic atrial fibrillation refractory to antiarrhythmic drugs. However, multiple procedures are often required to significantly reduce atrial fibrillation (AF) recurrence. In the present study, we analyzed the acute results and the midterm clinical outcome of a second-generation cryoballoon ablation (CB-A) performed during repeat procedures for recurrence of AF after an initial procedure performed with conventional radiofrequency (RF).

METHODS

Consecutive patients with paroxysmal and persistent AF who underwent pulmonary vein isolation by CB-A from June 2012 in our hospital as a redo procedure after a previous pulmonary vein isolation with RF were retrospectively included in this analysis.

RESULTS

Forty-seven patients having undergone CB-A as a redo procedure were considered for our analysis. Pulmonary vein potentials were documented in 83 pulmonary veins (PV) that were all successfully re-isolated using the CB-A. Transient phrenic nerve palsy was the only complication occurring in our study cohort. After a mean follow-up of 15 ± 8 months, 76.6% of patients were free from recurrence of atrial fibrillation. If taking into consideration a 3-month blanking period, 83% of patients were free from recurrence. The success rate in patients affected by paroxysmal AF was 87% at final follow-up following the blanking period.

CONCLUSIONS

The second-generation CB is effective in treating recurrence of AF after a previous ablation performed with conventional RF. Considering a 3-month blanking period, 83% of the patients were free from any atrial tachycardia recurrence during a 15-month follow-up. This approach proved particularly successful in patients affected by paroxysmal AF.

Pulmonary Vein Stenosis After Second-Generation Cryoballoon Ablation

BACKGROUND

Pulmonary vein stenosis (PVST) can occur after first-generation cryoballoon ablation. This study aimed to evaluate the incidence, severity, and characteristics of PVST after second-generation cryoballoon ablation.

METHODS

In total, 103 patients underwent PV isolation of paroxysmal atrial fibrillation using second-generation cryoballoons with a single big-balloon 3-minute freeze technique. Cardiac enhanced multidetector computed tomography (MDCT) was performed both before and a median of 6.0 (4.0-8.0) months after the procedure in all. PVST was classified as follows: minimal (<25%), mild (25-50%), moderate (50-70%), or severe (>70%).

RESULTS

In total, 406 PVs were analyzed. MDCT demonstrated PV stenosis in 10(2.5%) PVs among 8(7.8%) patients. In detail, minimal and mild PVSTs were observed in 6 and 4 PVs, respectively. PVST occurred in the left superior (LSPV), left inferior, and right superior PVs in 6, 1, and 3 PVs, respectively. No stenosis was observed in 15 PVs with active balloon deflations during freezing. All PVSTs had concentric patterns except for 2 PVs with minimal stenosis. Balloon deformities were observed during freezing of 2 PVs with mild stenosis. When the PVST was defined as a >25% decreased diameter, the incidence was 0.98% (4/406; including 3 LSPVs). PVST did not progress further during the follow-up period.

CONCLUSIONS

Although the incidence of PVST was low, it could occur even if a single big-balloon short freeze technique was applied. The risk of PV stenosis significantly differed among the 4 PVs, and reaching balloon temperatures of -60 °C and active balloon deflations during freezing were not associated with any PV stenosis.

Comparison of Phrenic Nerve Injury during Atrial Fibrillation Ablation between Different Modalities, Pathophysiology and Management

Atrial fibrillation ablation has emerged as an effective tool in the management of symptomatic atrial fibrillation. Currently, the electrophysiologists are striving to maximize the success while minimizing complications. Phrenic nerve injury (PNI) is one of the concerning complications, especially in cases of cryoballoon ablation. Due to anatomical proximity to atrial tissue, phrenic nerve is particularly susceptible to injury. With evolving monitoring techniques it is now possible to minimize the likelihood of a permanent PNI. However, the challenge remains to detect PNI at the earliest and to avoid further damage to the nerve. In this review, we discuss pertinent anatomical principles, techniques to avoid PNI and management in cases where PNI is encountered.

Incidence and Predictors of Complications During Cryoballoon Pulmonary Vein Isolation for Atrial Fibrillation

BACKGROUND

Cryoballoon pulmonary vein isolation (PVI) has emerged as an alternative to radiofrequency PVI for atrial fibrillation (AF). Data are lacking to define the rates and predictors of complications, particularly phrenic nerve injury (PNI).

METHODS AND RESULTS

We evaluated a single-center prospective registry of 450 consecutive patients undergoing cryoballoon PVI between 2011 and 2015. Patients were 59±10 years old, 26% were women, 58% had hypertension, their mean CHA2DS2VASc score was 1.7±1.3, 30% had persistent atrial fibrillation, and 92% received a second-generation 28-mm balloon. Predefined major complications were persistent PNI, pericardial effusion, deep vein thrombosis, arteriovenous fistula, atrioesophageal fistula, bleeding requiring transfusion, stroke, and death. PNI was categorized as persistent if it persisted after discharge from the laboratory. Logistic regression was performed to identify predictors of complications and specifically PNI. We identified a major complication in 10 (2.2%) patients. In 49 (10.8%) patients, at least transient PNI was observed; only 5 persisted beyond the procedure (1.1%). All cases of PNI resolved eventually, with the longest time to resolution being 48 days. We also describe 2 cases of PNI manifesting after the index hospitalization. Regression analysis identified 23-mm balloon use (16.3% versus 5.2%, odds ratio 2.94, P=0.011) and increased age (62.8±7.7 versus 58.7±0.12 years, odds ratio 1.058, P=0.014) as independent significant predictors of PNI. There were no significant predictors of major complications.

CONCLUSIONS

In a large contemporary cohort, cryoballoon PVI is associated with low procedural risk, including lower rates of PNI than previously reported. Older age and 23-mm balloon use were associated with PNI. Our low rate of PNI may reflect more sensitive detection methods, including compound motor action potential monitoring and forced double-deflation.

Femoral venous pressure waveform as indicator of phrenic nerve injury in the setting of second-generation cryoballoon ablation

AIMS

Femoral venous pressure waveform (VPW) analysis has been recently described as a novel method to assess phrenic nerve function during atrial fibrillation ablation procedures by means of the cryoballoon technique. In this study, we sought to evaluate the feasibility and effectiveness of this technique, with respect to the incidence of phrenic nerve injury (PNI), in comparison with the traditional abdominal palpation technique alone.

METHODS

Consecutive patients undergoing second-generation cryoballoon ablation (CB-A) from June 2014 to June 2015 were retrospectively analyzed. Diagnosis of PNI was made if any reduced motility or paralysis of the hemidiaphragm was detected on fluoroscopy.

RESULTS

During the study period, a total of 350 consecutive patients (man 67%, age 57.2 ± 12.9 years) were enrolled (200 using traditional phrenic nerve assessment and 150 using VPW monitoring). The incidence of PNI in the overall population was 8.0% (28/350); of these, eight were impending PNI (2.3%), 14 transient (4.0%), and six persistent (1.7%). Patients having undergone CB-A with traditional assessment experienced 18 phrenic nerve palsies (9.0%) vs two in 'VPW monitoring' group (1.3%; P = 0.002). Specifically, the former presented 12 transient (6.0%) and six persistent (3.0%) phrenic nerve palsies, and the latter exhibited two transient (1.3%; P = 0.03) and no persistent (0%; P = 0.04) phrenic nerve palsies.

CONCLUSION

In conclusion, this novel method assessing the VPW for predicting PNI is inexpensive, easily available, with reproducible measurements, and appears to be more effective than traditional assessment methods.

Prevalence and Pre-Procedural Predictors Associated With Right Phrenic Nerve Injury in Electromyography-Guided, Second-Generation Cryoballoon Ablation: Single Large Balloon and Single 3-Minute Freeze Techniques

OBJECTIVES

This study aimed to evaluate the incidence and pre-procedural predictors of right phrenic nerve injury (PNI) in electromyography-guided, second-generation cryoballoon (CB) ablation.

BACKGROUND

Second-generation CBs perform better pulmonary vein isolation (PVI) than first-generation CBs; however, right PNI remains a concern.

METHODS

One hundred consecutive patients with paroxysmal atrial fibrillation who underwent cryoablation were prospectively enrolled. Contrast-enhanced cardiac multidetector computed tomography (MDCT) was obtained pre-procedurally. PVI was performed with one 28-mm second-generation balloon using a 3-min freeze technique under electromyography guidance.

RESULTS

In all, 377 of 392 (96.2%) PVs were isolated using a CB. In 9 (9.0%) patients, right PNI was observed during the ablation of the right superior PV (RSPV). All events occurred during freezing, except for 1 that occurred during thawing. Right peri-cardiophrenic bundles (RPCBs) were identified at the level of the RSPV on MDCT in 97 patients. In the logistic regression analysis, the distance from the RSPV ostium to the RPCBs (hazard ratio: 0.263; 95% confidence interval [CI]: 0.110 to 0.630; p = 0.003) was the sole predictor of PNI. The optimal cutoff point for the distance for predicting right PNI was 12.4 mm (sensitivity 96.6%, specificity 88.9%) with an area under the curve of 0.968 (95% CI: 0.922 to 1.000). The PNI resolved spontaneously within 1 day and 2 months in 6 and 2 patients, respectively, and at 8 months in the remaining patient, with delayed recognition of an electromyography decrease.

CONCLUSIONS

Persistent right PNI is a rare complication during electromyography-guided, second-generation CB ablation. Electromyography should be monitored even during the thawing time. Pre-procedural MDCT might be useful for risk stratification of right PNI.

Procedural characteristics of pulmonary vein isolation using the novel third-generation cryoballoon

AIM

A novel third-generation cryoballoon (CB3) to perform pulmonary vein isolation (PVI) has recently been released, featuring a shortened distal balloon tip when compared with the second-generation (CB2), possibly allowing for enhanced intra-ablation pulmonary vein (PV) signal mapping. We aimed to investigate procedural efficacy and safety of the CB3 as compared to the CB2.

METHODS AND RESULTS

We studied 472 consecutive patients who underwent CB-PVI for paroxysmal or persistent atrial fibrillation (CB3: 49 patients; CB2: 423 patients). Detailed procedural data and in-hospital complications were registered in a prospective database. Complete PVI using the CB only was achieved in 98% of patients in each group. Single-freeze PVI was observed in 84/88% (CB2/CB3, P = n.s.) of the PVs. Time-to-PVI (TPVI) was 49 ± 32 (CB2) and 45 ± 27 s (CB3) (P = n.s.). Time-to-PVI determination rate was higher in the CB3 group (89.5 vs. 82.6%, P = 0.016). Signal noise due to ice formation on mapping electrodes occurred after 70 ± 46 s using CB3 and did not interfere with TPVI determination. Exchange of the spiral mapping catheter with a guide wire was more frequently required in the CB3 group (8.2 vs. 0.7% patients, P < 0.001). Balloon dislodgement during hockey stick manoeuvres occurred in 6.1% patients of the CB3 group only (P = 0.001). Complication rates were not different between the groups.

CONCLUSION

The CB3 offers a higher TPVI determination rate, facilitating dosing schemes based on TPVI, with equally high single-freeze efficacy compared with the CB2. The shortened distal tip of the CB3 requires adaptation of standard catheter manoeuvers to avoid balloon dislodgement.

Incidence of real-time recordings of pulmonary vein potentials using the third-generation short-tip cryoballoon

AIMS

The third-generation Cryoballoon Advance Short-tip (CB-ST) has been designed with a 40% shortened tip length compared with the former second-generation CB Advance device. Ideally, a shorter tip should permit an improved visualization of real-time (RT) recordings in the pulmonary vein (PV) due to a more proximal positioning of the inner lumen mapping catheter. In the present study, we sought to analyse the rate of visualization of RT recordings in our first series of patients with the CB-ST device.

METHODS AND RESULTS

All consecutive patients having undergone CB ablation using CB-ST technology were analysed. Exclusion criteria were the presence of an intracavitary thrombus, uncontrolled heart failure, moderate or severe valvular disease, and contraindications to general anaesthesia. A total of 60 consecutive patients (60.5 ± 11.2 years, 62% males) were evaluated. Real-time recordings were detected in 209 of 240 PVs (87.1%). Specifically, RT recordings could be visualized in 55 left superior PVs (91.7%), 51 left inferior PVs (85.0%), 53 right superior PVs (88.3%), and 50 right inferior PVs (83.3).

CONCLUSION

The rate of visualization of RT recordings is significantly high during third-generation CB-ST ablation. Real-time recordings can be visualized in ∼87.1% of veins with this novel cryoballoon.

Second-generation cryoballoon ablation for paroxysmal atrial fibrillation: Predictive role of atrial arrhythmias occurring in the blanking period on the incidence of late recurrences

BACKGROUND

Although consensus documents on catheter and surgical ablation of atrial fibrillation (AF) suggest a uniform "blanking period" of 3 months, recent evidence suggested that early recurrences of atrial tachyarrhythmias (ERATs) are strongly associated with late recurrences (LRs), especially if ERATs occurred in the last part of the "blanking period".

OBJECTIVE

The present study sought to assess the role of ERATs in predicting LRs in a large cohort of patients with paroxysmal AF who have undergone second-generation cryoballoon ablation.

METHODS

Consecutive patients with drug-resistant paroxysmal AF who underwent pulmonary vein isolation using CB-A technology as the index procedure were retrospectively included in our analysis. The exclusion criteria were any contraindications for the procedure, including the presence of an intracavitary thrombus, uncontrolled heart failure, contraindications to general anesthesia, and persistent AF.

RESULTS

A total of 331 consecutive patients (104 women [31%]; mean age 56.7 ± 13.3 years) were enrolled. Atrial tachyarrhythmias/AF recurrences were detected in 57 patients (17.2%). The highest prevalence of ERATs was observed in the first 2 weeks (55%) after pulmonary vein isolation. Of note, all the ERATs occurring 1.5 months after AF ablation relapsed after 3 months and were confirmed as definitive recurrences. Late recurrence of AF and atrial tachycardia occurred in 20 of 29 patients with ERATs (69.0%) and 28 of 302 patients without ERATs (9.3%) (P < .0001). A multivariate Cox regression analysis showed that the early recurrence within the blanking period was significantly and independently associated with an increased risk of developing a late recurrence (hazard ratio 6.79; 95% confidence interval 3.52-10.14; P < .0001).

CONCLUSION

Our findings reveal that ERATs are strongly associated with an LR after paroxysmal AF ablation using CB-A technology (hazard ratio 6.79; 95% confidence interval 3.52-10.14; P < .0001). Of note, when ERATs occurred later than 1.5 months, patients systematically experienced an LR.

One-year follow-up after second-generation cryoballoon ablation for atrial fibrillation in a large cohort of patients: a single-centre experience

AIM

The second-generation cryoballoon (CB-Adv) is effective in achieving pulmonary vein isolation (PVI) with encouraging results. In this study, we assessed the single-procedure outcome on a 1-year follow-up period in a large sample of patients having undergone PVI for drug-resistant atrial fibrillation (AF) using the CB-Adv.

METHODS AND RESULTS

A total of 393 patients (122 female, 31%; mean age 57.7 ± 12.9 years) with drug-refractory AF undergoing PVI using the novel CB-Adv were enrolled. Follow-up was based on outpatient clinic visits including Holter electrocardiograms. Recurrence of atrial tachyarrhythmias (ATas) was defined as a symptomatic or documented episode >30 s. A total of 1572 pulmonary veins (PVs) were identified and successfully isolated with 1.2 ± 0.3 mean freezes. Mean procedure and fluoroscopy times were 87.1 ± 38.2 and 14.9 ± 6.1 min, respectively. At a mean follow-up of 12 months, freedom from ATas after a single procedure was achieved in 85.8% of patients with paroxysmal atrial fibrillation and in 61.3% of patients with persistent AF (persAF). Similar success rates were observed between bonus freeze and single freeze strategies, 82.5 and 81.8%, respectively (P = 0.9). Multivariate analysis demonstrated that persAF (P = 0.04) and relapses during blanking period (BP) (P < 0.0001) were independent predictors of ATas recurrences.

CONCLUSION

Freedom from any ATa can be achieved in 81.9% of patients after a single CB-Adv procedure in a large cohort of patients. A bonus freeze does not influence the clinical outcome, and reducing the duration of the cryoapplication to 3 min offers excellent results. Persistent AF and arrhythmia recurrence during the BP are strong predictors of AF recurrence.

Phrenic nerve injury during ablation with the second-generation cryoballoon: analysis of the temperature drop behaviour in a large cohort of patients

AIMS

The present study sought to analyse the relationship between the temperature drop during the cryoenergy application and the occurrence of phrenic nerve injury (PNI) in a large cohort of patients having undergone second-generation cryoballoon ablation (CB-A).

METHODS AND RESULTS

The first 550 consecutive patients having undergone CB-A for atrial fibrillation were enrolled. Attained temperatures at 20, 30, 40, and 60 s during cryoablation in the right-sided pulmonary veins (PVs) were collected. Diagnosis of PNI was made if reduced motility or paralysis of the hemidiaphragm was detected. The incidence of PNI in the study population was 7.3% (40/550); among them, only four (0.7%) did not resolve until discharge and one (0.2%) still persisted at 23 months. Patients with PNI exhibited significantly lower temperatures at 20, 30, and 40 s after the beginning of the cryoapplication in the right superior PV (RSPV) (P = 0.006, P = 0.003, and P = 0.003, respectively). The temperature drop expressed as Δ temperature/Δ time was also significantly higher in patients with PNI. Low temperature during the early phases of the freezing cycle (less than -38°C at 40 s) predicted PNI with a sensitivity of 80.5%, a specificity of 77%, and a negative predictive value of 97.9%. Among patients with a fast temperature drop during RSPV ablation, an RSPV diameter >23.55 × 17.95 mm significantly predicted PNI occurrence.

CONCLUSION

The analysis of the temperature course within the first 40 s after the initiation of the freezing cycle showed that the temperature dropped significantly faster in patients with PNI during ablation in the RSPV.

Persistence of Phrenic Nerve Palsy Following 28-mm Cryoballoon Ablation: A Four-Year Single Center Experience

BACKGROUND

Phrenic nerve palsy (PNP) is the most frequently observed complication in the setting of cryoballoon (CB) ablation (Arctic Front, Medtronic Inc., Minneapolis, MN, USA). Although, usually transient, resolving before the end of the procedure, persistent PNP (not resolving before the end of procedure) can occur. Literature on persistent PNP after second generation CB ablation is relatively sparse.

METHODS

A total of 316 consecutive patients having undergone large 28-mm CB ablation as index procedure in the Heart Rhythm Management Center, UZ Brussels, Belgium, from January 2009 to December 2013 were retrospectively reviewed for the study. Of these 117 patients were treated with the first generation CB (CB1) and 199 patients with the second generation CB (CB2).

RESULTS

PNP occurred in 10% of the total population. Persistent PNP was only observed following CB2 ablation which occurred in 4.5% of the group. At a mean follow-up of 11 months, diaphragmatic contraction in persistent PNP patients resumed in 78% (7/9) of the patients. In a final follow-up at 5 and 20 months, PNP persisted in two patients, respectively. PNP during ablation in the right inferior pulmonary vein was only observed in the CB2 group. No predictors of persistency of PNP were observed.

CONCLUSION

Persistence of PNP only occurred in the CB2 group in 4.5% of patients. The majority of patients with persistent PNP were asymptomatic. In most of the patients having persistent PNP after ablation, complete phrenic nerve function resumed during follow-up (78%).

Incidence and characteristics of phrenic nerve palsy following pulmonary vein isolation with the second-generation as compared with the first-generation cryoballoon in 360 consecutive patients

AIMS

The second-generation cryoballoon (CB2) with increased surface cooling has recently become available. The aim was to investigate the incidence and characteristics of phrenic nerve palsy (PNP) during pulmonary vein isolation (PVI) using the CB2 as compared with the first-generation balloon (CB1).

METHODS AND RESULTS

A total of 360 consecutive patients with atrial fibrillation underwent PVI with the CB1 (106 patients) or the CB2 (254 patients). Right PN function was monitored by continuous stimulation and palpation during septal PV ablation. Persistent PNP (present at discharge) occurred in 2.8 and 1.9% (P = 0.63) of patients, transient PNP (full recovery before discharge) in 5.9 and 3.8% (P = 0.41) of patients in the CB2 and CB1 group, respectively. Phrenic nerve palsy during ablation at the right inferior PV was observed in 0% (CB1) and 4.3% (CB2, P = 0.03) of patients. Using the CB2, a trend of reduced incidence of persistent PNP over quartiles of consecutive patients was observed [4.8% (Q1) vs. 0% (Q4); P = 0.077]. At the culprit PV, PNP occurred after 3.5 ± 2.1 (CB1) and 1.1 ± 0.4 applications (CB2; P = 0.036). Complete recovery of PN function occurred after 29 ± 11 (CB1) and 259 ± 137 days (CB2; P = 0.004).

CONCLUSIONS

The rate of transient/persistent PNP associated with the use of the CB2 was 5.9 and 2.8%, respectively. Time to restitution of PN function was longer using the CB2.

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.