Validation of electrical ostial pulmonary vein isolation verified with a spiral inner lumen mapping catheter during second-generation cryoballoon ablation

Analysis of the effectiveness of the latest 4th-generation cryoballoon catheters in pulmonary vein isolation using high-resolution mapping

BACKGROUND

Long-term data showed that up to 27% of pulmonary veins are reconnected using cryoballoon ablation. This study aimed to evaluate the efficacy of the latest 4th-generation cryoballoon catheters using ultra high-resolution mapping.

METHODS

In patients with atrial fibrillation, a standard pulmonary vein isolation (PVI) with the latest 4th-generation cryoballoon catheter (Arctic Front Advance PRO, Medtronic Minneapolis, USA) and the spiral mapping catheter (Achieve Advance, Medtronic, Minneapolis, MN, USA) was performed. Subsequently, high-resolution mapping was achieved using the novel multipolar grid mapping catheter (Advisor HD Grid SE, Abbott Laboratories, USA). Follow-up was obtained after 6 months by means of a 7-day Holter electrocardiogram.

RESULTS

In our study, acute PVI was successfully achieved in all 31 patients. The latest 4th-generation cryoballoon catheter is safe in the acute phase of PVI. Additional high-resolution mapping (mean points per map 21,001 ± 4911) using the multipolar grid mapping catheter enabled us to identify residual gaps only in the carina pulmonary vein region; therefore, no additional ablation was performed. Three of 31 patients (10%) presented with atrial arrhythmia recurrence always related with pulmonary vein reconnection; using high-resolution mapping had no additional benefit in identifying pulmonary veins in which reconnection will occur.

CONCLUSION

The utility of additional high-density mapping, facilitated by the HD Grid catheter after PVI with the 4th-generation cryoballoon catheter do not substantiate a discernible advantage over conventional mapping methodologies, particularly, the spiral mapping catheter. Residual carinal conduction was observed in a substantial cohort of patients (48%), highlighting a persistent challenge in achieving complete electrical isolation.

Heart failure caused by iatrogenic atrial septal defect after cryoballoon ablation for atrial fibrillation

An 83-year-old man with no structural heart disease underwent pulmonary vein isolation (PVI) for symptomatic paroxysmal atrial fibrillation (AF). The PVI was successfully performed by cryoballoon ablation with a single transseptal puncture. A 12Fr deflectable sheath and an 8.5Fr long sheath crossed the interatrial septum via the same puncture site. Five months after PVI, the patient was readmitted because of heart failure and recurrence of AF. The echocardiogram showed a large (10.7 × 5.8 mm) iatrogenic atrial septal defect (IASD) at the previous puncture site. Both right-to-left and left-to-right shunts were observed during systole and diastole, respectively. Despite the initiation of optimal medical therapy for heart failure, symptoms were not completely controlled and IASD remained 11 months after PVI. Eventually, he received multiple additional PVI for recurrence of AF and percutaneous transcatheter closure (13 mm disc for 10.9 × 8.9 mm- IASD), then heart failure was controlled with the improvement of the right atrial and ventricular size. Although the induction of heart failure by IASD after PVI is rare, it should be noted as one of the causes, especially after cryoballoon ablation with simultaneous mapping catheter insertion via a single transseptal puncture. <Learning objective: Pulmonary vein isolation (PVI) is the established therapy for atrial fibrillation; however, it may cause several complications including iatrogenic atrial septal defect (IASD). IASD is less apparent than other complications, therefore it may be underrecognized. Although the induction of heart failure by IASD after PVI is rare, it should be noted as one of the causes, especially after cryoballoon ablation with simultaneous circular mapping catheter insertion via a single transseptal puncture.>.

Efficacy of temperature-guided cryoballoon ablation without using real-time recordings - 12-Month follow-up

Background

We sought to evaluate a temperature-guided approach of cryoballoon (CB) ablation without visualization of real-time recordings.

Methods and results

We analysed 166 patients (34.9% female, 60 ± 11 years) with paroxysmal or short-term persistent atrial fibrillation (AF). Comorbidities included diabetes mellitus (n = 28), coronary artery disease (n = 24), hypertension (n = 122), previous stroke or TIA > 3 months (n = 12). Cryoablation of the pulmonary veins (PV) was performed using first-generation (n = 78) and second-generation CB (n = 88). Two 5-minute freezes were performed for the first-generation and two 4-minute freezes for the second-generation CB with the intention to achieve a temperature drop below −40 °C. At 12-month follow-up, we observed overall freedom from AF in 92 patients (56.6%, mean time to AF recurrence 3.4 ± 2.9 months). There was a significant difference in freedom from AF between first-generation CB (45%) and second-generation CB (67%; p < 0.005). Complications were groin hematoma (4.8%) and phrenic nerve palsy (PVP) (2.4%). PVP disappeared after 12 months in all patients. Three patients developed cardiac tamponade (1.8%) that resolved without further sequelae after pericardiocentesis. Multivariate analysis revealed that only the achieved temperature in the right inferior PV (RIPV) was a predictor of long-term freedom from AF (OR 0.9; p = 0.014). Female gender was a predictor of AF recurrence (OR 6.1; p = 0.022).

Conclusion

Temperature-guided CB ablation without real-time recordings is feasible and safe without reducing the efficacy if second-generation CB is used. Deep nadir temperatures especially in the RIPV are necessary for long term-success.

Thromboembolic Risks of the Procedural Process in Second-Generation Cryoballoon Ablation Procedures

Background

Atrial fibrillation ablation is associated with substantial risks of silent cerebral events (SCEs) or silent cerebral lesions. We investigated which procedural processes during cryoballoon procedures carried a risk.

Methods and Results

Forty paroxysmal atrial fibrillation patients underwent pulmonary vein isolation using second-generation cryoballoons with single 28-mm balloon 3-minute freeze techniques. Microembolic signals (MESs) were monitored by transcranial Doppler throughout all procedures. Brain magnetic resonance imaging was obtained pre- and post-procedure in 34 patients (85.0%). Of 158 pulmonary veins, 152 (96.2%) were isolated using cryoablation, and 6 required touch-up radiofrequency ablation. A mean of 5.0±1.2 cryoballoon applications was applied, and the left atrial dwell time was 76.7±22.4 minutes. The total MES counts/procedures were 522 (426–626). Left atrial access and Flexcath sheath insertion generated 25 (11–44) and 34 (24–53) MESs. Using radiofrequency ablation for transseptal access increased the MES count during transseptal punctures. During cryoapplications, MES counts were greatest during first applications (117 [81–157]), especially after balloon stretch/deflations (43 [21–81]). Pre– and post–pulmonary vein potential mapping with Lasso catheters generated 57 (21–88) and 61 (36–88) MESs. Reinsertion of once withdrawn cryoballoons and subsequent applications produced 205 (156–310) MESs. Touch-up ablation generated 32 (19–62) MESs, whereas electric cardioversion generated no MESs. SCEs and silent cerebral lesions were detected in 11 (32.3%) and 4 (11.7%) patients, respectively. The patients with SCEs were older than those without; however, there were no significant factors associated with SCEs.

Conclusions

A significant number of MESs and SCE/silent cerebral lesion occurrences were observed during second-generation cryoballoon ablation procedures. MESs were recorded during a variety of steps throughout the procedure; however, the majority occurred during phases with a high probability of gaseous emboli.