Double factor single shot to diminish complications in cryoballoon ablation procedures for atrial fibrillation

Single-shot technique of cryoablation for atrial fibrillation has comparable effective and safety outcomes compared to standard technique: insights from multiple clinical studies

Background

Although there are many freezing protocols available, the optimal freezing dose is still not determined. We aimed to evaluate the effectiveness and safety of different freeze strategies of CBA in the treatment of AF.

Methods

PubMed, Cochrane Library, Web of Science, and Embase were searched up to 1st December 2022. Studies comparing the outcomes between single-shot technique and standard technique of cryoablation were included. Subgroup analysis identified potential determinants for single-shot technique procedure.

Results

Our search resulted in 3407 records after deduplication. A total of 17 qualified studies met our inclusion criteria. Compared with standard technique, single-shot technique of cryoablation has a comparable rate of freedom from AF/AT(RR 1.00; P = 0.968), a trend for lower rate of procedure complications (RR 0.80; P = 0.069), a lower rate in transient phrenic paralysis (t-PNP) (RR 0.67; P = 0.038), a similar rate in persistent phrenic paralysis (per-PNP) (RR 1.15; P = 0.645), as well as a comparable procedure parameters. Importantly, potentially significant treatment covariable interactions in procedure complications were found in freeze strategy subgroup, male proportion subgroup and age subgroup, including single-shot freeze (RR 1.02; P = 0.915) and TTI-guided (RR 0.63; P = 0.007) with interaction P = 0.051, high male proportion (RR 0.54; P = 0.005) and a low male proportion (RR 0.94; P = 0.759) with interaction P = 0.074, as well as age ≥ 65 (RR0.91; P = 0.642) and age <65 (RR 0.54; P = 0.006),interaction P = 0.090. Meanwhile, only one significant treatment covariable interactions in procedure complications was found in the hypertension subgroup, including HT > 60% (RR 0.89; P = 0.549) and HT ≤ 60% (RR 0. 46; P < 0.01) with interaction P = 0.043.

Conclusions

Our study suggested that single-shot technique of cryoablation has comparable effective and safety outcomes for AF ablation compared to standard technique.

Effectiveness and safety of a time to isolation strategy of cryoballoon ablation of atrial fibrillation: A systematic review and meta-analysis

AIM

We conducted a systematic review and meta-analysis of randomized and observational studies with a control group to evaluate the effectiveness and safety of a time to isolation (TTI)-based strategy of cryoballoon ablation (CBA) in the treatment of atrial fibrillation (AF).

METHODS

Three electronic databases (MEDLINE, Cochrane Central Register of Controlled Trials, and Embase) without language restrictions were searched. The intervention assessed was a TTI-based strategy of CBA in the treatment of AF. TTI was defined as the time from the start of freezing to the last recorded pulmonary veins' potential. The comparison of interest was intended conventional protocol of CBA. The primary endpoint was freedom from atrial arrhythmia.

RESULTS

Nine studies were deemed eligible (N = 2289 patients). Eight studies reported freedom from atrial arrhythmia and pooled results showed a marginally similar success rate between the two protocols (odds ratio [OR]: 1.24; 95% confidence interval [CI]: 0.98-1.56). A prespecified subgroup analysis verified that a high dose TTI strategy (with >120 s duration of cryotherapy post-TTI) compared to the conventional protocol could significantly increase the patients without atrial arrhythmia during follow-up (OR: 1.39; 95% CI: 1.05-1.83). TTI strategy could also significantly decrease total procedure time (SMD: -26.24 min; 95% CI: -36.90 to -15.57) and phrenic nerve palsy incidence (OR: 0.49; 95% CI: 0.29-0.84).

CONCLUSION

Moderate confidence evidence suggests that an individualized CBA dosing strategy based on TTI and extended (>2 min post-TTI) duration of CBA is accompanied by fewer recurrences post-AF ablation.

Improved real-time recordings using the fourth-generation cryoballoon technology-detection of dual fascicle electrograms

BACKGROUND

We aimed to analyze the rate of visualization of real-time (RT) recordings and dual fascicle electrograms in our first series of patients treated with the fourth-generation cryoballoon (CB) device.

METHODS

All consecutive patients who underwent CB ablation using the fourth-generation technology were included in the analysis. In all procedures, we used a 28-mm CB placed via a single transseptal puncture guided by intracardiac ultrasound. A 20-mm octapolar intraluminal circular catheter was used for intracardiac recordings. A single 180-s freeze strategy was employed.

RESULTS

A total of 129 patients (72.9% male, mean age 60.1 ± 10.9 years) were enrolled in the study. RT recordings were detected in 445 (86.2%) pulmonary veins (PVs). Specifically, RT recordings were visualized in 115 left superior PVs (89.2%), 107 left inferior PVs (82.9%), 118 right superior PVs (91.4%), and 105 right inferior PVs (81.3%). Dual fascicle electrograms could be observed only in patients in sinus rhythm, in 23 of 396 PVs (5.8%). They were most commonly observed in the left superior PV (8.1%), somewhat less in both inferior veins (6.1%), while this phenomenon was least frequent in the right superior PV (3.0%).

CONCLUSIONS

By using the fourth-generation CB, we report a specific pattern of isolation represented by a sequential isolation of two apparently distinct PV fascicles during a single CB freeze delivery. This phenomenon occurred in 5.8% of PV ablations. Of note, the rate of visualization of RT isolation with this novel CB was very high and could be documented in 86.2% of PVs.

Cryoablation for atrial fibrillation

Cryoballoon ablation for the treatment of atrial fibrillation has established itself as an effective and efficient modality for achieving pulmonary vein isolation. Over the past 13 years more than 100,000 Cryoballoon ablation procedures have been performed with the first to fourth generation cryoballoons. Over that time there have been significant advances in our understanding regarding the optimal procedural techniques. The purpose of this "topic in review" is to focus on the practical aspects of performing a Cryoballoon ablation procedure, within the context of the contemporary literature. Specifically there is a focus on how contemporary studies can inform clinical decision making and ensure operators are able to perform a safe and effective procedure.

Cryoballoon ablation dosing: From the bench to the bedside and back

To date, multiple modes of research have been leveraged to study the optimal cryoballoon ablation parameters to safely, effectively, and efficiently isolate the pulmonary veins for the treatment of atrial fibrillation. Basic scientific investigation, preclinical studies, clinical observations, trials, and, more recently, computational modeling have helped to generate and test new hypotheses for the advancement of cryoballoon treatment in patients with atrial fibrillation. In this review, we examine the data and evidence that have contributed to the development of patient-tailored dosing strategies that are currently used for pulmonary vein isolation by using the Arctic Front series of cryoballoon ablation catheters.