Different time course effect of autonomic nervous modulation after cryoballoon and hotballoon catheter ablations for paroxysmal atrial fibrillation

BACKGROUND

Few studies have reported on the quantitative evaluation of autonomic nerve modification after balloon ablation. Therefore, this study aimed to evaluate the effects of cryoballoon and hotballoon ablations on the autonomic nervous system (ANS) and their relationship with prognosis.

METHODS

We included 234 patients who underwent cryoballoon ablation (n = 190) or hotballoon ablation (n = 44) for paroxysmal atrial fibrillation. Heart rate variability (HRV) analysis was performed on all patients using a 3-min electrocardiogram at baseline, 1, 3, 6, and 12 months after ablation. HRV parameters and prognoses were compared between the two balloon systems.

RESULTS

Ln low-frequency (LF), Ln high-frequency (HF), standard deviation of the R-R intervals (SDNN), and RR intervals significantly decreased after 1 month in both groups, but the changes were more pronounced in the cryoballoon group than in the hotballoon group. In contrast, HRV indices in the hotballoon ablation group decreased gradually and reached their lowest point 3-to-6 months after the procedure, which was later than in the cryoballoon ablation group. The recurrence rate did not differ between the two groups. HRV parameters changed similarly in the cryoballoon group, regardless of recurrence. However, patients with recurrence had significantly higher SDNN and Ln LF at 12 months than those without recurrence in the hotballoon group (41.2 ± 39.3 ms vs. 18.5 ± 12.6 ms, p = 0.006, and 2.2 ± 0.7 ms² vs. 1.5 ± 0.7 ms², p = 0.003, respectively).

CONCLUSIONS

The time course of HRV changes differed between cryoballoon and hotballoon ablations. Hence, the two balloon systems may have distinct effects on the ANS and its role in prognosis.

Cryoballoon ablation for atrial fibrillation: Effects on neuromodulation

Pulmonary vein isolation (PVI) represents the mainstay of atrial fibrillation (AF) ablation, and PVI with cryoballoon catheter (CB) ablation (CB-A) has proven to be as effective and safe as radiofrequency ablation (RF-A). Although AF is initiated by triggers arising from the pulmonary veins (PV) and non-PV foci, the intrinsic cardiac nervous system (ICNS) plays a significant role in the induction and maintenance of AF. The ICNS is an epicardial neural system composed of ganglionated plexi (GPs) and a complex network of interconnecting neurons. In the left atrium, the major GPs are located in proximity to the PV-left atrial junction. Vagal reactions have been described as markers of autonomic modulation during PVI with both RF-A and CB-A. The occurrence of neuromodulation during PVI with CB-A may be explained by both the anatomical relationship between the GPs and the PVs and the characteristics of the CB. Due to the CB/PV size mismatch, the CB creates a wide ablation area that extends from the PV ostium toward the antrum, possibly including the GPs. Although targeted GPs ablation, as a supplemental strategy to PVI, has been associated with a better AF outcome in patients undergoing RF-A, the additional clinical benefit of neuromodulation during PVI with CB-A remains a matter of debate. In this review, we provide an overview of the anatomy of the ICNS, the relationship between the ICNS and AF pathophysiology, and the current evidence on the clinical relevance of neuromodulation during PVI with CB-A.

Does a Vagal Response Indicate Cardiac Autonomic Modulation and Improve the Therapeutic Effect of Pulmonary Vein Isolation in Patients with Paroxysmal Atrial Fibrillation? Insights from Cryoballoon Ablation

Background: The incidence and influence of vagal response (VR) observed during cryoballoon-based pulmonary vein isolation (CBA-based PVI) on the cardiac autonomic nervous system (CANS) and ablation outcomes in paroxysmal atrial fibrillation (PAF) remain unknown. Methods: 296 patients were treated with a 28 mm second-generation cryoballoon (Medtronic). A total of 74 patients without structural heart disease and concomitant diseases were chosen for a detailed CANS assessment with a heart rate variability (HRV) analysis. All patients were screened over a 2-year post-ablation period. Results: VR was detected in 30% of patients and included sinus arrest (64%) or severe sinus bradycardia (46%). The presence of VR was not related to PV ostial dimension, patient clinical characteristics or intraprocedural ablation details. CANS modulation, manifesting as increased median HR and decreased HRV parameters with intact sympatho-vagal balance occurred independently of VR presence or absence and sustained for at least 12 months following ablation. VR was not related with more intensive CANS modulation and did not translate into better ablation outcomes when compared to the non-VR group (74% vs. 71% at 12 months and 69% vs. 65% at 24 months respectively). Conclusions: VR is frequent during CBA-based PVI for PAF and unrelated to any additional clinical benefit.

High vagal tone predicts pulmonary vein reconnection after cryoballoon ablation for paroxysmal atrial fibrillation

BACKGROUND

Pulmonary vein (PV) isolation is an established treatment for paroxysmal drug-refractory atrial fibrillation (AF). High parasympathetic tone and reconnection of PVs have demonstrated to be possible culprits of AF recurrence after ablation. Our aim was to investigate the association between parasympathetic tone and reconnected PVs in patients with paroxysmal AF.

METHODS

Consecutive patients who underwent a redo catheter ablation procedure for atrial tachyarrhythmia recurrence by means of 3D electroanatomic mapping with documentation of presence or absence of PVs reconnection following an initial procedure of cryoballoon (CB) ablation for symptomatic drug-refractory paroxysmal AF were screened for the study.

RESULTS

A total of 92 patients were included, of whom 50 (54.35%) were males. Reconnected PVs were found in 64 (69%) patients. PVs reconnection could be predicted by DC (C-statistic = .770), by SDNNI (C-statistic = .714) and by absolute VLF power (C-statistic = .722), while right-sided PVs reconnection could be better predicted by DC (C-statistic = .848) and by SDNNI (C-statistic = .761). In multivariate binary logistic regression analysis, a DC value ≥6.45 ms and an absolute VLF power value ≥160 ms² were associated with three times and five times higher odds of PVs reconnection, respectively. On a vein-per-vein analysis, absolute VLF power ≥160 ms² was associated with three times higher odds, while reaching of -40°C within 60 s was associated with three times lower odds of PVs reconnection.

CONCLUSION

High parasympathetic tonus accurately predicts PVs reconnection. On a vein-per-vein analysis, parasympathetic markers along with biophysical parameters predicted PVs reconnection. On a case-by-case analysis, parasympathetic markers were the only predictors of PVs reconnection, thus being a robust PVs reconnection prediction tool.

A novel strategy to treat vaso-vagal syncope: Cardiac neuromodulation by cryoballoon pulmonary vein isolation

Background

Clinical management of vaso-vagal syncope (VVS) remains challenging since no therapy has proven to completely prevent VVS recurrence.

Objective

The purpose of this study was to analyze the mid-term outcome of cryoballoon (CB) cardioneuroablation achieved by pulmonary vein isolation (PVI) in patients with VVS.

Methods

Patients who underwent CB cardioneuroablation in our centers between January 2014 to June 2018 were included. All patients had a history of VVS or pre-syncope despite therapeutic attempts with medical and/or pacing treatments. Patients were excluded in case of structural heart diseases, cerebrovascular diseases or suspected drug-related syncope. Both heart rate (HR) and atrio-ventricular (AV) interval were analyzed on the 12-lead electrocardiogram (ECG) the day before the procedure, the day after, and in the follow-up.

Results

In total, 26 patients (76.9% males, 37.5 ± 9.0 years old) were included. All patients underwent a successful procedure with the 28 mm second-generation Arctic Front Advance CB. No major complication occurred. At a mean follow-up of 20.1 ± 11.6 months the freedom from VVS or reflex pre-syncope was 83,7%, with 22 patients free from any clinical recurrence. Basal HR significantly increased the day after the procedure (57.2 bpm vs 78.3 bpm, p < 0.001), while at the final follow-up it stabilized at a value halfway between the 2 previous ones (69.8 bpm, p = 0.0086). The AV interval didn’t modify significantly after the procedure.

Conclusion

Endocardial autonomic denervation achieved by CB PVI appears to be an effective and safe treatment option for patients with refractory VVS and reflex pre-syncope.

Conversion of atrial fibrillation to sinus rhythm during cryoballoon ablation: A favorable and not unusual phenomenon during second-generation cryoballoon pulmonary vein isolation

BACKGROUND

The prevalence and the clinical impact of conversion of atrial fibrillation (AF) to sinus rhythm (SR) during cryoballoon ablation (CB-A) are unknown.

OBJECTIVE

The purpose of this study was to evaluate the prevalence of restoration of SR during CB-A and the clinical impact of this phenomenon.

METHODS

Between January 2012 and September 2018, all patients who experienced conversion of AF to SR during CB-A were included. This group was subsequently matched for gender, age, type of AF, diagnosis-to-ablation time, and left atrial size with patients who underwent CB-A and did not experienced conversion of AF to SR. After discharge, patients were scheduled for follow-up visits at 1, 3, 6, and 12 months and 24 hours Holter recordings were obtained at each follow-up visit. All documented AF episodes of >30 seconds were considered as recurrence. A 3 month post-procedural blanking period (BP) was applied.

RESULTS

A total of 1559 patients underwent pulmonary veins isolation by CB-A between January 2012 and September 2018; among them, 58 patients (3.7%) experienced restoration of SR during CB-A. In total, 53 patients (41 males [77.3%], mean age 61.4 ± 13.3 years) were included in the case group. During CB-A, restoration of SR occurred more frequently during right-side PVs applications (right inferior pulmonary vein 39.6%, right superior pulmonary vein 30.2%). If considering a BP, at 2 year follow-up, freedom from recurrences was 86.5% in the case group and 68.0% in the control group (P = .036).

CONCLUSION

Conversion of AF to SR is a favorable and relatively frequent phenomenon during cryoballoon pulmonary vein isolation ablation.

Predictors of cardiac neuromodulation achieved by cryoballoon ablation performed in patients with atrial fibrillation who were in sinus rhythm before the ablation

BACKGROUND

The impact of pulmonary vein isolation (PVI) performed with cryoballoon (CB) on the intrinsic cardiac autonomic nervous system (ICANS) remains unclear.

OBJECTIVE

The purpose of this study was to evaluate the predictors and the clinical meaning of cardiac neuromodulation achieved by CB-ablation as assessed by sinus heart rate (HR) response after the procedure.

METHODS

Patients who underwent CB-ablation for drug-resistant atrial fibrillation (AF) from January 2014 to October 2018 were included. Twelve‑leads rest ECG was taken both before and after the procedure. After discharge, patients were scheduled for follow-up visits at 1, 3, 6, and 12 months and 24 h Holter recordings were obtained at each follow-up visit. All documented AF episodes of >30 s were considered as recurrence.

RESULTS

Four-hundred seventy-two patients (62.3% male, age 56.7 ± 13.6 years, 97.2% paroxysmal AF) were included. Mean HR before the procedure was 60.17 ± 10.4 bpm, while the morning after the procedure mean HR was 75.48 ± 12.0 bpm. Age at enrollment (R = -0.26; p < 0.001), baseline HR before the CB-A (R = -0.32; p < 0.001), nadir temperature in each right pulmonary vein (R = -0.11, p = 0.022; R = -0.16; p = 0.001) were significantly associated with the ∆HR. At 2-year follow-up, freedom from recurrences was 83.1% for the patients with HR increase ≥15 bpm after CB-A and 66.3% in patients with HR increase ˂15 bpm (p = 0.021).

CONCLUSION

Sinus HR increase is a frequent phenomenon after CB-A, that can be predicted by both clinical and procedural factors and that correlates with better outcome after cryo-PVI.

Pulmonary vein isolation and beyond: Predictive value of vagal reactions in second-generation cryoballoon ablation for the outcome of persistent atrial fibrillation

BACKGROUND

Cryoballoon ablation (CBA) is gaining increasing acceptance in the treatment of persistent (per) atrial fibrillation (AF). The cardiac autonomic nervous system plays a pivotal role in the regulation of AF.

OBJECTIVE

We evaluated the impact of vagal reactions (VRs), as a surrogate marker for autonomic nervous system modulation, on the outcome of CBA in patients (pts) with perAF.

METHODS

A total of 250 consecutive pts (mean age 63.9 ± 10.0 years; 175 pts, 70% male) undergoing primary second-generation CBA for perAF were studied. VRs were defined as bradycardia <40 beats/min, asystole, or higher-degree atrioventricular block. Follow-up visits at 3, 6, and 12 months included 7-day Holter electrocardiograms.

RESULTS

VRs were recorded in 61 pts (24%). These pts showed a significantly reduced recurrence rate of AF (5%) than did those without VRs (log-rank, P < .01). Univariate Cox regression analyses confirmed VRs as a strong predictor of AF-free survival (hazard ratio [HR] 0.10; P < .01). Female sex (HR 1.71; P = .02), preprocedural tachycardia (HR 1.01; P = .01), and AF (HR 1.75; P = .01) before CBA at admission were revealed as predictors of AF recurrence. Multivariate regression model calculation solely identified VRs (HR 0.11; 95% confidence interval 0.03-0.34; P < .01) and male sex (HR 0.57; 95% confidence interval 0.36-0.89; P = .01) as independent predictors of AF-free survival.

CONCLUSION

VR is an independent predictor of AF-free survival after CBA for perAF.

Avoidance of Vagal Response During Circumferential Pulmonary Vein Isolation

Background:

Circumferential pulmonary vein isolation (CPVI) often cause unavoidable vagal reflexes during procedure due to the coincidental modification of ganglionated plexus which are located on pulmonary vein (PV) antrum. The right anterior ganglionated plexi (RAGP) which located at superoanterior area of right superior PV antrum is an essential station to regulate the cardiac autonomic nerve activities and is easily coincidentally ablated during CPVI. The aim of this study is to assess the effect of RAGP ablation on vagal response (VR) during CPVI.

Methods:

A total of 80 patients with paroxysmal atrial fibrillation who underwent the first time CPVI were prospectively enrolled and randomly assigned to 2 groups: group A (n=40), CPVI started with right PVs at RAGP site; group B (n=40): CPVI started with left PVs first, and the last ablation site is RAGP. Electrophysiological parameters include basal cycle length, A-H interval, H-V interval, sinus node recovery time, and atrioventricular node Wenckebach point were recorded before and after CPVI procedure.

Results:

During CPVI, the positive VR were only observed on 1 patient in group A and 25 patients in group B ( P <0.001). A total of 21 patients with positive VR in group B needed for temporary ventricular pacing during procedure, while the only patient with positive VR in group A did not need for temporary ventricular pacing ( P <0.001). Compared with baseline, basal cycle length, sinus node recovery time, and atrioventricular node Wenckebach point were decreased significantly after CPVI procedure in both groups (all P <0.05) and without differences between 2 groups.

Conclusions:

Circumferential PV isolation initiated from RAGP could effectively inhibit VR occurrence and significantly increase heart rate during procedure.

Recent advances in cryoballoon ablation for atrial fibrillation

Introduction: Pulmonary vein isolation (PVI), by catheter ablation, represents the current treatment for drug-resistant atrial fibrillation (AF). Nowadays cryoballoon (CB) is a recognized ablation method in patients with atrial fibrillation, mainly due to its ease of use, leading to reproducible and fast procedures. This novel single shot technology literally revolutionized the approach to AF ablation. Areas covered: The historical development of the cryoballoon, ablation techniques and new approaches beyond the ordinary PVI and complications are summarized here. Expert opinion: Although cryoballoon ablation has greatly standardized the approach to PVI a few critical points still need to be clarified scientifically in order to further uniform this procedure in cath labs worldwide. Duration and dosage of the cryoapplication is undoubtedly a topic of great interest.

Impact of cryoballoon-guided pulmonary vein isolation on non-invasive autonomic tests in patients with paroxysmal atrial fibrillation

Background

Pulmonary vein isolation (PVI) modulates the intrinsic cardiac autonomic nervous system (ANS). We evaluated the impact of PVI on 5 non-invasive autonomic tests.

Methods

Thirty patients (76% male, mean age 60.37 ± 9.02 years) with paroxysmal atrial fibrillation (AF) underwent cryoballoon-guided PVI. Five autonomic tests were performed 24hrs before and after PVI (N = 30) and repeated after 6months (N = 22). Parasympathetic function was measured by heart rate (HR) variability during deep breathing (E/I ratio, I-E difference), Valsalva maneuver (Valsalva-ratio) and head-up tilt test (30/15 ratio). Sympathetic function was measured by systolic BP response to sustained handgrip and 10’ tilting and by diastolic BP response to cold water.

Results

24hrs after PVI, baseline HR increased from 57.93 ± 9.06 bpm to 71.10 ± 12.75 bpm (p < 0.001). At 6 months, baseline HR was lower than immediately post-PVI (62.59 ± 7.89 vs 71.36 ± 13.58 bpm, p = 0.032) but still higher in comparison to pre-PVI (62.59 ± 7.89 vs 57.09 ± 8.80 bpm, p < 0.001). No differences were seen in baseline BP and parasympathetic tests acutely and at 6months. Besides an acute lowering in systolic BP increase during handgrip test, all sympathetic tests remained unchanged.

Conclusions

An acute HR increase attenuated at 6months and an acute lowered systolic BP response to sustained handgrip were the only changes after cryoballoon-guided PVI. Non-invasive autonomic tests seem therefore not appropriate to evaluate the autonomic modulatory effect of PVI, either due to a too limited sensitivity or a too localized effect of PVI to influence test results.