Safety and feasibility of electrical isolation of the superior vena cava in addition to pulmonary vein ablation for paroxysmal atrial fibrillation using the cryoballoon: lessons from a prospective study.

PURPOSE: The purpose of this study was to evaluate the feasibility and safety of superior vena cava (SVC) isolation in addition to standard pulmonary vein isolation (PVI) using the second-generation cryoballoon (CB) in patients with paroxysmal atrial fibrillation. METHODS: Thirty-seven consecutive patients that underwent CB ablation for paroxysmal atrial fibrillation (PAF) were prospectively enrolled in our study. After PVI the SVC was mapped for potentials. If the SVC exhibited electrical activity, isolation was achieved performing a single 180-s balloon application. RESULTS: Regarding SVC isolation, 180-s freeze in the SVC could be completed in 32 (86.4%) patients, and 5 patients had at least 120 s of freezing application (13.5%). Real-time recording during SVC isolation was observed in 30 (81.0%) patients. The mean time to isolation was 36.9 ± 28.7 s and the temperature at isolation was - 33 (- 15 to - 40) °C. No cases developed persistent phrenic nerve palsy (PNP) or any other complication. CONCLUSIONS: Superior vena cava isolation proved to be safe and feasible with the second generation cryoballoon in a prospective series of patients affected by PAF.

Early repolarization pattern as a predictor of atrial fibrillation recurrence following radiofrequency pulmonary vein isolation.

BACKGROUND: Early repolarization patterns (ERP) have been found to be associated with poor cardiovascular end points. We aimed to evaluate the ERP prevalence among patients with structurally normal hearts undergoing radiofrequency (RF) pulmonary vein isolation (PVI) for paroxysmal atrial fibrillation (AF) ablation and its association with the AF recurrence. METHODS: All consecutive patients who underwent RF-PVI as index procedure for paroxysmal AF in our center were evaluated. EXCLUSION CRITERIA: structural heart disease, ongoing use of Class I/III antiarrhythmics, complete-bundle-branch-block. Lateral (I, aVL, V5 -V6 ), inferior (II, III, aVF), or infero-lateral (both) ERP were defined in baseline ECG as horizontal/downsloping J-point elevation ≥1 mm in two consecutive leads with QRS slurring/notching. Documented episodes of AF lasting ≥30 s were considered recurrence. RESULTS: Of 701 cases, 434 patients (305 males, 58 ± 11 years) were included for analysis. ERP observed in 67 patients (15.4%) (Infero-lateral n = 26, inferior n = 23, lateral n = 18) which were significantly younger, demonstrating longer PR-interval and lower heart rates. At a mean follow-up of 22.1 ± 9.7 months, AF recurrences were found in 107 patients (24.6%). In middle-aged patients (≥40-<60 years; n = 206, 79% male), those with an infero-lateral ERP had higher recurrence compared with the ones without (56.3% vs. 19%; p = 0.002). Infero-lateral ERP was significantly predicting recurrence (HR 2.42, 95% CI 1.21-4.82; p = 0.01). CONCLUSION: Early repolarization patterns was more prevalent in our AF population than in the general population. Infero-lateral ERP in baseline ECG might predict AF recurrence in the follow-up after RF-PVI in middle-aged patients.

Second generation cryoballoon ablation for atrial fibrillation in young adults: midterm outcome in patients under 40 years of age.

Aims: Pulmonary vein isolation (PVI) has been demonstrated more effective in young patients, in which the substrate for atrial fibrillation (AF) is probably more confined to pulmonary vein potentials. The present study sought to focus on the midterm outcomes in patients under 40 years having undergone PVI with the Cryoballoon Advance because of drug resistant AF. Methods and results: Between June 2012 and December 2015, 57 patients having undergone Cryoballoon ablation (CB-A) below 40 years of age for AF in our centre were retrospectively analysed and considered for our analysis. All patients underwent this procedure with the 28 mm Cryoballon Advance. All 227 veins were successfully isolated without the need for additional focal tip ablation. Median follow-up was 18 ±10 months. The freedom from AF after a blanking period of 3 months was 88% in our cohort of patients younger than 40 years old. The most frequent periprocedural complication was related to the groin puncture and occurred in 2 patients. After a single procedure, the only univariate predictor of clinical recurrence was the diagnosis of hypertrophic cardiomyopathy. Conclusion: Young patients affected by AF can be effectively and safely treated with CB-A that grants freedom from AF in 88% of the patients at 18 months follow-up following a 3-month blanking period. All veins could be isolated with the large 28 mm Cryoballoon Advance only.

Learning curve using the second-generation cryoballoon ablation.

AIMS: To study the learning curve with the second-generation cryoballoon technology focusing on safety, efficacy and procedural characteristics. METHODS: We included 300 patients (men 64.6%, mean age 58.3 ±â€Š12.4 years), 240 of whom were treated by four operators without prior experience in atrial fibrillation ablation and compared them with 60 consecutive patients treated by senior operator. To study the learning curves, we divided the study period into two trimesters and analyzed procedure duration, fluoroscopy times, complications, characteristics of the freeze-thaw cycles and midterm outcomes. RESULTS: Hands-on help from senior operators to achieve pulmonary vein isolation was needed only in the first study trimester (24.1%), most commonly to achieve right inferior pulmonary vein isolation (55.2%). The mean procedure duration shortened from 76.7 ±â€Š17.4 to 65.1 ±â€Š11.4 min (P < 0.0001), and fluoroscopy time decreased from 18.5 ±â€Š7.3 to 12.1 ±â€Š4.3 min (P < 0.0001) for first and second trimester, respectively, and approached senior operator's results (58.2 ±â€Š12.8 and 8.7 ±â€Š4.5 min). Most of the major complications (one stroke, four pseudoaneurysms and one retroperitoneal hematoma) occurred during the first study trimester. Most characteristics of the freeze cycles remained unchanged in both study periods. Compared with junior operators, the senior operator achieved lower nadir temperatures in both inferior veins. However, there was no significant difference in midterm outcomes between junior and senior operators (79.5 vs 83.3%, P = 0.589). CONCLUSION: The learning curve with the second-generation cryoballoon is steep. Inexperienced operators, trained in high-volume centers, can achieve pulmonary vein isolation safely and efficiently with short procedure and fluoroscopy times after having performed 20-30 cases.

Single 3-Minute versus Double 4-Minute Freeze Strategy for Second-Generation Cryoballoon Ablation: A Single-Center Experience.

INTRODUCTION: Second-generation cryoballoon (CB-Adv) ablation is highly effective in achieving pulmonary vein isolation (PVI) with promising mid-term clinical outcome. However, the ideal freezing strategy is still under debate. The aim of this study was to assess the efficacy of a single 3-minute approach compared to the conventional 4-minute plus bonus application using CB-Adv. METHODS AND RESULTS: One hundred and sixty patients (67% male; mean age 58.0 ± 13.3 years) underwent PVI using CB-Adv for paroxysmal atrial fibrillation (PAF). Among 160 patients, 80 received a single 3-minute approach (3-mns group), while the remaining 80 conventional 4-minute plus bonus-freeze (4-mns group). Mean procedure and fluoroscopy times were 90.6 ± 15.8 and 18.3 ± 6.9 in the 4-mns group, 75.2 ± 17.1 and 13.5 ± 8.7 in the 3-mns group (P < 0.001, respectively). First-freeze isolation rate was 91.6% in the 4- versus 90.6% in the 3-mns group (P = 0.78). Persistent phrenic nerve palsy (PNP) occurred in 6/80 (3.5%) in the 4-mns group and 4/80 in the 3-mns group (P = 0.75). The overall freedom from ATas 2 years after the procedure was 78.1% (125/160): 77.5% (62/80 patients) in the 3-mns and 78.8% (63/80 patients) in the 4-mns group (P = 0.82). In multivariate analysis, time to PVI and nadir temperature independently predicted ATa recurrences (P < 0.001). CONCLUSIONS: CB-Adv ablation for PAF is highly effective, resulting in 78% 2-year freedom from arrhythmic recurrences. A "single 3-minute strategy" showed equal efficacy as compared to the conventional 4-minute plus bonus freeze approach at 2-year follow-up, providing shorter procedure and fluoroscopy time. Nadir temperature and time to PVI were predictors of arrhythmic recurrences. "Bonus-freeze" strategy might be unnecessary.

Second-Generation Cryoballoon Ablation in the Setting of Lone Paroxysmal Atrial Fibrillation: Single Procedural Outcome at 12 Months.

BACKGROUND: Lone atrial fibrillation (LAF) develops in younger individuals without cardiovascular or pulmonary disease. As pulmonary vein isolation has been recognized as an optimal treatment for drug-resistant atrial fibrillation, cryoballoon ablation with second-generation balloon (CB-A) may be an ideal solution for LAF patients. OBJECTIVE: The aim of this study was to investigate acute success, periprocedural complications and outcome over a 12-month follow-up period in a cohort of patients having undergone PV isolation (PVI) for LAF using CB-A technology. METHODS: A total of 75 consecutive patients (50 male, mean age 47 ± 12 years) with a diagnosis of lone paroxysmal atrial fibrillation who underwent pulmonary vein isolation (PVI) by CB-A from June 2012 were included. All patients underwent this procedure with the 28 mm CB-A. A total of 299 PVs (100%) could be isolated with CB-A alone. RESULTS: The freedom from AF recurrence after a single procedure was 92% of patients during the entire 13-month follow-up. When considering a blanking period (BP) of 3 months, success rate was 93.3%. Transient phrenic nerve palsy (PNP) was the most frequent complication, occurring in 5.3% of individuals (4 patients); complete recovery was documented for all of these patients prior to hospital discharge. CONCLUSIONS: CB-A is extremely effective in achieving PVI and affords freedom from AF at 13-month follow-up in 93% of young patients affected by drug-resistant LPAF following a 3-month BP. The most frequent complication observed was PNP, which reverted prior to discharge in all patients.

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.

Improved visualisation of real-time recordings during third generation cryoballoon ablation: a comparison between the novel short-tip and the second generation device.

BACKGROUND: 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 (CB-A). Ideally, a shorter tip should permit an improved visualisation of real-time recordings in the pulmonary vein (PV) due to a more proximal positioning of the inner lumen mapping catheter. We sought to compare the incidence of visualisation of real-time recordings in patients having undergone ablation with the CB-ST with patients having received CB-A ablation. METHODS: All patients having undergone CB ablation using CB-ST technology and the last 500 consecutive patients having undergone CB-A ablation were analysed. Exclusion criteria were the presence of an intracavitary thrombus, uncontrolled heart failure, moderate or severe valvular disease, and contraindications to general anaesthesia. RESULTS: A total of 600 consecutive patients (58.1 ± 12.9 years, 64 % males) were evaluated (100 CB-ST and 500 CB-A ablations). Real-time recordings were significantly more prevalent in the CB-ST population compared with CB-A group (85.7 vs 67.2 %, p < 0.0001). Real-time recordings could be more frequently visualised in the CB-ST group in all types of veins (LSPV 89 vs 73.4 %, p = 0.0005; LIPV 84 vs 65.6 %, p = 0.0002; RSPV 87 vs 67.4 %, p < 0.0001; RIPV 83 vs 62.4 %, p < 0.0001). CONCLUSION: The rate of visualisation of real-time recordings is significantly higher during third-generation CB-ST ablation if compared to the second-generation CB-A device. Real-time recordings can be visualised in approximately 85.7 % 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.

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.

Repeat Procedures After Hybrid Thoracoscopic Ablation in the Setting of Longstanding Persistent Atrial Fibrillation: Electrophysiological Findings and 2-Year Clinical Outcome.

INTRODUCTION: In order to increase success rates of invasive treatment of persistent atrial fibrillation, the hybrid approach was developed, combining video-assisted thoracoscopic epicardial procedure with conventional endocardial catheter ablation. Currently, there are no reports of electrophysiological findings and clinical outcomes of repeat procedures after the hybrid approach. METHODS AND RESULTS: Out of 64 patients who were treated by hybrid ablation for persistent atrial fibrillation (AF), 14 underwent the repeat catheter ablation and were selected for this study. All 14 patients initially presented with longstanding persistent atrial fibrillation and markedly dilated atria. The hybrid procedure was performed in a single act and the mean time to redo procedure was 346 ± 227 days. In 57% of patients indication for redo procedure was regular atrial tachycardia, and the rest presented with recurrent atrial fibrillation. In 36% of patients, recovered conduction was found along the previous ablation lesions. Only 9% of pulmonary veins were reconnected (0.36 veins per patient) and 7% of box lesions were not complete. The overall success rate at 2 years follow-up after the repeat procedure, including second repeat procedure and patients taking antiarrhythmic drugs, was 64% (57% without drugs and further ablation). One case of moderate pulmonary vein stenosis was detected as a consequence of hybrid procedure. CONCLUSION: Hybrid atrial fibrillation ablation results in durable lesions and high rates of chronic pulmonary vein isolation even after long-term follow-up. Most of the repeat procedures after the hybrid approach are related to left atrial flutters that could be successfully treated by catheter ablation.

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.

Impact on Clinical Outcome of Premature Interruption of Cryoenergy Delivery Due to Phrenic Nerve Palsy During Second Generation Cryoballoon Ablation for Paroxysmal Atrial Fibrillation.

INTRODUCTION: Right phrenic nerve paralysis (PNP) is the most frequently observed complication occurring during cryoballoon ablation (CB). Our aim was to analyze the impact of the premature interruption (PI) of cryoenergy delivery in a large series of consecutive patients during ablation in the right-sided veins on clinical outcome. METHODS AND RESULTS: All consecutive patients having undergone second-generation CB ablation for paroxysmal atrial fibrillation (AF) from July 2012 to September 2014 were included in our analysis. Exclusion criteria were persistent AF, presence of an intracavitary thrombus, uncontrolled heart failure, moderate or severe valvular disease, left atrium (LA) diameter ≥55 mm, and contraindications to general anesthesia. A total 287 consecutive patients with drug-resistant paroxysmal AF having undergone pulmonary vein isolation by means of CB technology (male 65%, age 57.6 ± 13.1 years) were included. The incidence of PNP in the study population was 8.0% (23/287). At a mean follow-up of 11.5 ± 3.9 months, the success rate without antiarrhythmic therapy was 81.6%. Patients with PNP had similar rates of AF recurrence compared with those without PNP (17.4% vs. 17.8%; P = 0.9); the former had a mean follow-up of 10.9 ± 3.7 months, the latter 11.8 ± 4.5 months (P = 0.3). CONCLUSION: Conclusion: Our findings show that patients in whom freezing was interrupted due to PNP had a similar outcome on 1-year follow-up compared with those in whom freezing cycles were completed in the septal veins. No baseline clinical or procedural characteristics were found to predict AF recurrence in patients having experienced PNP.