Second-generation cryoballoon for pulmonary vein isolation in patients with pulmonary vein abnormality: Safety, efficacy and lessons from re-ablation procedures

Global Research Progress on Radiofrequency Ablation in Cardiology

Radiofrequency ablation (RFA) has become a cornerstone in treating cardiac arrhythmias, offering a minimally invasive approach to managing conditions such as atrial fibrillation, ventricular tachycardia, and other rhythm disorders. The historical evolution of RFA, from its early inception to its current state, underscores the technological advancements that have significantly enhanced its efficacy and safety. Global trends indicate a steady increase in the adoption of RFA, with notable research contributions from North America, Europe, and Asia. Comparative studies reveal outcome variability driven by differences in patient populations, procedural techniques, and healthcare infrastructures. Despite its success, RFA faces challenges, including complications related to the procedure, patient selection, and long-term efficacy. Emerging technologies, such as integrating artificial intelligence and enhanced imaging modalities, hold promise for overcoming these barriers and further refining the procedure. Gaps in current research are identified, particularly in understanding the long-term outcomes of RFA and its application in complex arrhythmias. The critical role of RFA in modern cardiology is emphasized, along with the potential for future innovations that could expand its therapeutic utility. This synthesis of the latest evidence provides valuable insights for optimizing the use of RFA in managing cardiac arrhythmias.

Comprehensive analysis of recurrence factors in cryoballoon AF ablation: integrating clinical, biomarkers, and echocardiographic parameters

Atrial fibrillation (AF) poses substantial challenges in cardiovascular diseases, impacting patient health and economic burdens. Understanding the mechanical effects of AF on the left atrium (LA) and assessing the influence of treatment modalities on LA functions are critical. This study aims to assess the efficacy of echocardiographic and biochemical parameters in predicting AF recurrence following second generation cryoballoon ablation (CB-2). Ninety-two patients with symptomatic AF, treated with CB-2 at Istanbul University-Cerrahpaşa, Faculty of Medicine, Department of Cardiology, were prospectively examined from January 2021 to July 2023. The study endeavors to develop a predictive model for AF recurrence, investigating the relationship between echocardiographic measurements and serum biomarkers with recurrence. The follow-up duration for echocardiographic assessments and biochemical analyses was systematically documented. The study revealed a significant enhancement in LA mechanical functions during echocardiographic follow-ups three months post-procedure. Specifically, LA strain parameters emerged as significant predictors of recurrence (LAsr: 95%CI 1.004-1.246, p = 0.047; LAsct: 95%CI 1.040-1.750, p = 0.024). Biochemical analyses demonstrated a correlation between elevated PRO-BNP levels and an increased risk of recurrence (95%CI 1.000-1.003, p = 0.012). Moreover, specific biomarkers such as MYBPHL, which demonstrated increased levels post-procedure, were deemed indicative of atrial damage, suggesting potential additional atrial substrate modification beyond PVI. Consequently, improvements in LA function post-cryoballoon ablation and biochemical markers have surfaced as potential indicators for predicting AF recurrence. This study elucidates the effectiveness of CB-2 in treating AF and its impact on LA functions. Notably, LA strain measurements and PRO-BNP levels have emerged as reliable indicators for predicting recurrence. Beyond clinical implications, our research establishes a foundation for a deeper understanding of the role of CB-2 in AF management and factors associated with recurrence.

Very high-power short-duration catheter ablation for treatment of cardiac arrhythmias: Insights from the FAST and FURIOUS study series

The QDOT MICRO™ Catheter is a novel open-irrigated contact force-sensing radiofrequency ablation catheter. It offers very high-power short-duration (vHPSD) ablation with 90 W for 4 s to improve safety and efficacy of catheter ablation procedures. Although the QDOT MICRO™ Catheter was mainly designed for pulmonary vein isolation (PVI) its versatility to treat atrial fibrillation (AF) and other types of arrhythmias was recently evaluated by the FAST and FURIOUS study series and other studies and will be presented in this article. Available study and registry data as well as case reports concerning utilization of the QDOT MICRO™ Catheter for the treatment of cardiac arrhythmias including AF, focal and macroreentry atrial tachycardia, typical atrial flutter by cavotricuspid isthmus block, premature ventricular contractions, and accessory pathways were reviewed and summarized. In summary, the QDOT MICRO™ Catheter showed safety and efficacy for PVI and is able to treat also other types of arrhythmias as is was recently evaluated by case reports and the FAST and FURIOUS studies.

Acute procedural efficacy and safety of a novel expandable diameter cryoballoon in atrial fibrillation ablation: Early results from a multicenter ablation registry

INTRODUCTION

The major limitation of the current cryoballoon (CB) system is a fixed 28 mm balloon-size. We sought to analyze real-world early experience with novel-sized adjustable CB.

METHODS

This multicenter observational study included 140 consecutive atrial fibrillation patients (71 years, 94 men, 86 paroxysmal) who underwent pulmonary vein (PV) isolation using expandable diameter CB capable of ablation at 28 or 31 mm.

RESULTS

Out of 544 targeted PVs, 526 (96.7%) were successfully isolated by a size-adjustable CB with a 770 [690-870] second median application dose, while the remaining 18 required touch-up ablation. Among them, 326 (62.0%) PVs were isolated by a 31 mm balloon, and the rate was significantly higher for upper than lower PVs (73.0% vs. 45.7%, p < .0001) and highest for right superior (78.5%) and lowest for right inferior (39.9%) PVs. The biophysical parameters and time to isolation were comparable between the 28 and 31 mm balloons, however, the real-time PV potential monitoring capability was significantly higher for 31 mm than 28 mm balloons for the left superior PV. The esophageal temperature reached 15°C during left inferior PV ablation significantly more often with 31 mm than 28 mm balloons (43.1% vs. 18.2%, p = .008). Right phrenic nerve injury (PNI) occurred in 9 (6.4%) patients during applications (6 right superior, 2 right inferior PVs), and most occurred with a 31 mm balloon.

CONCLUSIONS

Our real-world early data demonstrated high acute efficacy and safety of the novel-sized adjustable CB. The biophysical parameters were similar between the 28 and 31 mm balloons. No marked decrease in the incidence of PNI was observed even with 31 mm balloons.

Left atrial functions in the early period after cryoballoon ablation for paroxysmal atrial fibrillation

PURPOSE

In patients with paroxysmal atrial fibrillation (PAF), functional changes are observed in the left atrium (LA) after pulmonary vein isolation (PVI) procedure. Although previous studies have investigated the altered mechanical functions of the LA with radiofrequency (RF) ablation, changes in the LA functions in the early period after cryoablation (CB-2) have not been clearly demonstrated. This study aims to explore the early periodical changes in mechanical functions of the LA in patients with PAF who underwent CB-2 based ablation through the help of echocardiographic methods which contain Doppler and strain parameters.

METHODS

Consecutive 77 patients (mean age: 57.5 ±  11.2; 57% men) with PAF underwent CB-2 were prospectively analyzed. All patients were in sinus rhythm before and after the procedure. The LA dimensions, the LA reservoir strain, the LA atrial contractile strain and the LA conduit strain and left ventricular diastolic function parameters were evaluated by Doppler echocardiography before and 3 months after the procedure.

RESULTS

Acute procedural success was achieved in all cases. No major complications were observed. LA reservoir strain and LA contractile strain showed significant recovery after the procedure. (28.3 ± 12.8 vs. 34.6 ± 13.8, p < .001 and -10.8 ± 7.9 vs. -13.9 ± 9.3, p = .014 respectively). No significant change was demonstrated in other echocardiographic parameters.

CONCLUSION

Significant improvement in mechanical functions may occur even in the early period after cryoballoon ablation in patients with PAF.

Catheter Ablation for Atrial Fibrillation in Patients ≤30 Years of Age

Pulmonary vein (PV) automaticity is an established trigger for paroxysmal atrial fibrillation (PAF), making PV isolation (PVI) the cornerstone of catheter ablation. However, data on triggers for atrial fibrillation (AF) and catheter ablation strategy in very young patients aged <30 years are sparse. A total of 51 young patients (mean age 24.0 ± 4.2 years, 78.4% men) with drug-refractory PAF underwent electrophysiology (EP) study and ablation at 5 EP centers. None of the patients had structural heart disease or family history of AF. EP study induced supraventricular tachycardia (SVT) in 12 patients (n = 12, 23.5%): concealed accessory pathway mediated orthodromic atrioventricular reentrant tachycardia in 3 patients, typical atrioventricular nodal reentrant tachycardia in 6 patients, left superior PV tachycardia in 1 patient, left atrial appendage tachycardia in 1 patient, and typical atrial flutter in 1 patient. In patients with induced SVTs, SVT ablation without PVI was performed as an index procedure, except for the patient with atrial flutter who received cavotricuspid isthmus ablation in addition to PVI. Remaining patients underwent radiofrequency (n = 15, 29.4%) or second-generation cryoballoon-based PVI (n = 24, 47%). There were no major complications related to ablation procedures. Follow-up was based on outpatient visits including 24-hour Holter-electrocardiogram at 3, 6, and 12 months after ablation, or additional Holter-electrocardiogram was ordered in case of symptoms suggesting recurrence. Recurrence was defined as any atrial tachyarrhythmia (ATA) episode >30 seconds after a 3-month blanking period. A total of 2 patients with atrioventricular nodal reentrant tachycardia, 1 with left atrial appendage tachycardia, experienced AF recurrence within the first 3 months and received PVI. After the 3-month blanking period, during a median follow-up of 17.0 ± 10.1 months, 44 of 51 patients (86.2%) were free of ATA recurrence. In the PVI group, 33 of 39 patients (84.6%) experienced no ATA recurrence. In conclusion, SVT substrate is identified in around a quarter of young adult patients with history of AF, and targeted ablation without PVI may be sufficient in the majority of these patients. PVI is needed in the majority and is safe and effective in this population.

Evaluation of predictive scores for late and very late recurrence after cryoballoon-based ablation of atrial fibrillation

Purpose

Studies on predictive scores for very late recurrence (VLR) (recurrence later than 12 months) after second-generation cryoballoon-based pulmonary vein isolation (CB2-PVI) are sparse. We aimed to evaluate the frequency of late recurrence (LR) (later than 3 months) and VLR, and to validate predictive scores for LR and VLR after initial CB2-PVI.

Methods

A total of 288 patients undergoing initial CB2-PVI (66 ± 11 years, 46% paroxysmal) were retrospectively enrolled in the LR cohort. In the VLR cohort, 83 patients with recurrence within 3–12 months or with < 12-month follow-up were excluded. The predictive scores of arrhythmia recurrence were assessed, including the APPLE, DR-FLASH, PLAAF, BASE-AF₂, ATLAS, SCALE-CryoAF, and MB-LATER scores.

Results

During a mean follow-up of 15.3 ± 7.1 months, 188 of 288 (65.2%) patients remained in sinus rhythm without any recurrences. Thirty-two of 205 (15.6%) patients experienced VLR after a mean of 16.6 ± 5.6 months. Comparing the predictive values of these specific scores, the MB-LATER score showed a reliable trend toward greater risk of both LR and VLR (area under the curve in LR; 0.632, 0.637, 0.632, 0.637, 0.604, 0.725, and 0.691 (p = ns), VLR; 0.612, 0.636, 0.644, 0.586, 0.541, 0.633, and 0.680 (p = 0.038, vs. BASE-AF₂, respectively)). Kaplan-Meier analysis estimated patients with higher MB-LATER scores which had favorable outcomes (24-month freedom from LR; 26.0% vs. 56.7%, p < 0.0001, VLR; 53.4% vs. 82.1%, p = 0.013).

Conclusion

The MB-LATER score provided more reliable predictive value for both LR and VLR. Patients with higher MB-LATER scores may benefit from more intensive long-term follow-up.

Relationship between psychological factors and atrial fibrillation: A meta-analysis and systematic review

BACKGROUND

Although several studies have investigated the role of psychological factors in atrial fibrillation (AF), the results are still under debate. Therefore, we performed a meta-analysis to examine the relationship between psychological factors and the risk of incident AF.

METHODS

We systematically searched the PubMed and EMBASE databases from inception to December 2019 to identify eligible studies. The hazard ratios (HRs) with 95% confidence intervals (CIs) were pooled by using a random-effects model.

RESULTS

A total of 11 cohort studies were included in this meta-analysis. There were 5, 2, 4, and 5 studies examining the association of anxiety, anger, depression, and psychological stress with AF, respectively. In the pooled analysis by a random-effects model, anxiety (HR = 1.10, 95%CI 0.97-1.24; P = .14), anger (HR = 1.08, 95%CI 0.95-1.23; P = .21), depression (HR = 1.15, 95%CI 0.98-1.35; P = .08), and work stress (HR = 1.14, 95%CI 0.98-1.34; P = .09) were not associated with the risk of AF. These results were not changed when we re-performed the analysis using a fixed-effects model.

CONCLUSIONS

Based on current evidence, no associations were observed for anger, anxiety, and work stress with the risk of AF.

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.

Association between gene variants and the recurrence of atrial fibrillation: An updated meta-analysis

BACKGROUND

Studies showed the controversial results about the effect of common genetic polymorphisms on the atrial fibrillation (AF) recurrence. We performed the systematic review and meta-analysis to qualify the association between common genetic polymorphisms and AF recurrence.

METHODS

Articles were systematically retrieved PubMed, Web of Science, EMBASE, Wanfang, and CNKI database and 9 studies including 3204 patients were enrolled in our meta-analysis.

RESULTS

Results showed that the associations were significant under rs2200733 3 genetic models (TT vs CC: odds ratio [OR] [confidence interval [CI]] = 1.336 [1.061-1.683], P = .014; CT vs CC: OR [CI] = 0.759 [0.614-0.937], P = .01; TT vs CT + CC: OR [CI] = 2.308 [1.440-3.700], P = .001). The association was significant under rs10033464 genetic model (TT vs GG: OR [CI] = 1.517 [1.165-1.976], P = .002).

CONCLUSIONS

Rs13376333 on chromosome 1q21 (in KCNN3), rs7193343 and rs2106261 on chromosome 16q22 (in ZFHX3) were not associated with AF recurrence in our meta-analysis. In total, our meta-analysis found that rs2200733 and rs10033464 on chromosome 4q25 (near PITX2) were associated with the risk of AF recurrence.

Alternative strategies to improve success rate of mitral isthmus block

Achieving bidirectional conduction block (BDB) across the mitral isthmus (MI) is technically challenging. We describe our experience using different ablation strategies for achieving successful MI block.We reviewed the records of patients who had undergone MI ablation for peri-mitral (PM) flutter at our institution from January 2010 to May 2015. We investigated ablation strategies for achieving MI block and their long-term outcomes in terms of recurrence of atrial tachyarrhythmia.Single endocardial MI ablation with or without distal coronary sinus (CS) ablation achieved MI block in 129 out of 236 (54.7%) patients. After failure of MI block, a new MI line ablation, ablation targeting the vein of Marshall (VOM), or anterior line ablation was performed in selected patients. The MI block was achieved in 13 (52.0%) out of 25 patients with new MI line ablation and in 13 (68.4%) out of 19 patients with VOM ablation. Anterior line ablation was tried in 23 patients and the line of block was achieved in 12 (52.2%) patients. Finally, overall PM BDB (PMB, MI block or anterior line block) was achieved in 167 (70.8%) of 236 patients. The incidence atrial tachyarrhythmia was similar between the patients with successful PMB and those with failed PMB (32.9% vs 42.0%, P = .18). In multivariable Cox regression analysis, the PMB was not associated with recurrence of atrial tachyarrhythmia (hazard ratio [HR]: 0.70, 95% confidence interval [CI]: 0.43-1.12).In conclusion, single endocardial MI line with or without distal CS ablation showed limited success for achieving MI block. Additional substrate modifications such as a new MI line ablation, anterior line ablation, or ablation targeting the VOM may improve the success rate of PMB block. However, the benefits of PMB were not clear in this study.