Outcomes of adjunct posterior wall isolation in atrial fibrillation patients with cardiac implantable electronic devices.

BACKGROUND: Although pulmonary vein isolation (PVI) remains the cornerstone of catheter ablation of atrial fibrillation (AF), several studies have illustrated clinical benefits associated with PVI with posterior wall isolation (PWI). METHODS: This retrospective study investigated the outcomes of PVI alone versus PVI+PWI performed using the cryoballoon in patients with cardiac implantable electronic devices (CIEDs) and paroxysmal AF (PAF) or persistent AF (PersAF). RESULTS: Acute PVI was achieved in all patients using cryoballoon ablation. Compared to PVI alone, PVI+PWI was associated with longer cryoablation, fluoroscopy, and total procedure times. Adjunct radiofrequency was required to complete PWI in 29/77 patients (37.7%). Adverse events were similar with PVI alone versus PVI+PWI. But at 24 ± 7 months of follow-up, not only cryoballoon PVI+PWI was associated with improved freedom from recurrent AF (74.3% vs. 46.0%, P = .007) and all atrial tachyarrhythmias (71.4% vs. 38.1%, P = .001) in patients with PersAF, cryoballoon PVI+PWI also yielded greater freedom from AF (88.1% vs. 63.7%, P = .003) and all atrial tachyarrhythmias (83.3% vs. 60.8%, P = .008) in those with PAF. Additionally, PVI+PWI was associated with higher reductions in atrial tachyarrhythmia burden (97.9% vs. 91.6%, P < .001), need for cardioversion (5.2% vs. 23.6%, P < .001) and repeat catheter ablation (10.4% vs. 26.1%, P = .005), and a longer time-to-arrhythmia recurrence (16 ± 6 months vs. 8 ± 5 months, P < .001) in both PersAF and PAF patients. CONCLUSION: In CIED patients with PersAF or PAF, cryoballoon PVI+PWI is associated with a greater freedom from recurrent AF and atrial tachyarrhythmias, as compared to PVI alone during long-term follow-up.

Same-day discharge after cryoballoon ablation of atrial fibrillation: A multicenter experience.

BACKGROUND: It is common practice to observe patients during an overnight stay (ONS) following a catheter ablation procedure for the treatment of atrial fibrillation (AF). OBJECTIVES: To investigate the safety and economic impact of a same-day discharge (SDD) protocol after cryoballoon ablation for treatment of AF in high-volume, geographically diverse US hospitals. METHODS: We retrospectively reviewed 2374 consecutive patients (1119 SDD and 1180 ONS) who underwent cryoballoon ablation for AF at three US centers. Baseline characteristics, acute procedure-related complications, and longer-term evaluations of safety were recorded during routine clinical follow-up. The mean cost of an ONS was used in a one-way sensitivity analysis to evaluate yearly cost savings as a function of the percentage of SDD cases per year. RESULTS: The SDD and ONS cohorts were predominately male (69% vs. 67%; p = .3), but SDD patients were younger (64 ± 11 vs. 66 ± 10; p < .0001) with lower body mass index (30 ± 6 vs. 31 ± 61; p < .0001) and CHA2 DS2 -VASc scores (1.4 ± 1.0 vs. 2.2 ± 1.4; p < .0002). There was no difference between SDD and ONS in the 30-day total complication rate (n = 15 [1.26%] versus n = 24 [2.03%]; p = .136, respectively). The most common complication was hematoma in both the SDD (n = 8; 0.67%) and ONS (n = 11; 0.93%) cohorts. Sensitivity analysis demonstrated that when 50% of every 100 patients treated were discharged the same day, hospital cost savings ranged from $45 825 to $83 813 per year across US hospitals. CONCLUSIONS: SDD following cryoballoon ablation for AF appears to be safe and is associated with cost savings across different US hospitals.

Outcomes of catheter ablation of ventricular tachycardia with mechanical hemodynamic support: An analysis of the Medicare database.

INTRODUCTION: There is a paucity of data in favor of mechanical support during catheter ablation of ventricular tachycardia (VT). This study investigated the outcomes of VT ablation associated with mechanical support using percutaneous ventricular assist device (PVAD) versus intra-aortic balloon pump (IABP). METHODS AND RESULTS: We retrospectively examined the outcomes of patients who underwent VT ablation associated with PVAD versus IABP from 2010 to 2013, captured by the Medicare Inpatient Standard Analytic File database. Data from 345 patients (PVAD = 230, IABP = 115) were examined. On admission, the incidence of heart failure was higher in PVAD (84.3% vs. 73.0%; P = 0.01) with similar rates of renal failure in PVAD versus IABP (33.0% vs. 37.4%; P = 0.42). However, PVAD was associated with reduced in-hospital cardiogenic shock (9.1% vs. 23.5%; P  <  0.001), renal failure (11.7% vs. 21.7%; P = 0.01), and length of stay (8.4 ± 7.9 vs. 10.6 ± 7.5; P < 0.001), but with greater hospital discharges to home/self-care (66.0% vs. 51.6%; P = 0.02). Index mortality (6.5% vs. 19.1%; P = 0.001) and mortality in patients with cardiogenic shock (18.2% vs. 41.2%; P = 0.03) were significantly lower with PVAD versus IABP. Furthermore, PVAD was associated with lower all-cause (27.0% vs. 38.7%; P = 0.04) and heart failure-related (21.4% vs. 33.3%; P = 0.03) 30-day hospital readmissions, but with similar redo-VT ablation rates at 1 year (10.2% vs. 14.0%; P = 0.34). CONCLUSION: Among the cases captured by the Medicare database, catheter ablation of VT associated with mechanical support using PVAD was associated with reduced in-hospital cardiogenic shock, renal failure, length of stay, hospital readmissions and mortality, but no difference in redo-VT ablation at 1 year.

Impact of Pulmonary Vein Cryoballoon Ablation on Bronchial Injury.

INTRODUCTION: There is a paucity of data on the mechanisms of cough and hemoptysis that sometimes ensue from cryoballoon ablation of pulmonary veins (Cryo-PV). This study specifically examined the impact of ultra-cold (≤-60 °C, 3 minutes), prolonged (>-55 °C, 6 minutes), and conventional (>-55 °C, 3 minutes) Cryo-PV on lung/bronchial injury. METHODS AND RESULTS: Four healthy adult swine underwent Cryo-PV. Each animal received Cryo-PV to the inferior common trunk and the right superior PV. In 2 animals, 1 PV was treated with 2 ultra-cold (Cryo-AUltra-cold ) and the other with 2 conventional (Cryo-AConventional ) cryoapplications. In the other 2 animals, 1 PV was ablated using 2 prolonged (Cryo-BProlonged ) and the other with 2 conventional (Cryo-BConventional ) applications. The nadir cryoballoon temperatures were lower in Cryo-AUltra-cold versus Cryo-AConventional (-66 ± 6 °C vs. -45 ± 5 °C; P = 0.001), but did not differ between Cryo-BProlonged and Cryo-BConventional (-46 ± 3 °C vs. -49 ± 3 °C; P = 0.123). Post-ablation bronchoscopy revealed immediate mucosal edema and erythema with/without bleeding in the adjacent bronchi in 100% of Cryo-AUltra-cold and 50% of Cryo-AConventional /Cryo-BConventional and Cryo-BProlonged . At 4 hours post-ablation, there were marked increases in bronchoalveolar macrophages (P <0.001), lymphocytes (P = 0.035) and neutrophils (P = 0.001). Furthermore, Cryo-AUltra-cold yielded the largest increase in the macrophage (P = 0.005) and neutrophil (P = 0.034) cell counts. While similar trends were seen in Cryo-BProlonged , these did not reach statistical significance. CONCLUSION: Cryo-PV can elicit acute bronchial inflammation, bleeding, and mucosal injury. While this was further augmented by ultra-cold cryoapplications, it was also evident to a lesser degree with prolonged and even conventional cryoapplications. The mechanism for this appears to be direct collateral injury.

Acute and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second-Generation Cryoballoon versus Open-Irrigated Radiofrequency: A Multicenter Experience.

INTRODUCTION: There are limited comparative data on catheter ablation of atrial fibrillation (CAAF) using the second-generation cryoballoon (CB-2) versus point-by-point radiofrequency (RF). This study examines the acute/long-term CAAF outcomes using these 2 strategies. METHODS AND RESULTS: In this multicenter, retrospective, nonrandomized analysis, procedural and clinical outcomes of 1,196 patients (76% with paroxysmal AF) undergoing CAAF using CB-2 (n = 773) and open-irrigated, non-force sensing RF (n = 423) were evaluated. Pulmonary vein isolation was achieved in 98% with CB-2 and 99% with RF (P = 0.168). CB-2 was associated with shorter ablation time (40 ± 14 min vs. 66 ± 26 min; P < 0.001) and procedure time (145 ± 49 minutes vs. 188 ± 42 minutes; P < 0.001), but greater fluoroscopic utilization (29 ± 13 minutes vs. 23 ± 14 minutes; P < 0.001). While transient (7.6% vs. 0%; P < 0.001) and persistent (1.2% vs. 0%; P = 0.026) phrenic nerve palsy occurred exclusively with CB-2, other adverse event rates were similar between CB-2 (1.6%) and RF (2.6%); P = 0.207. However, freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 (76.6%) versus RF (60.4%); P < 0.001. While this difference was evident in patients with paroxysmal AF (P < 0.001), it did not reach significance in those with persistent AF (P = 0.089). Additionally, CB-2 was associated with reduced long-term need for antiarrhythmic therapy (16.7% vs. 22.0%; P = 0.024) and repeat ablations (14.6% vs. 24.1%; P < 0.001). CONCLUSION: In this multicenter, retrospective, nonrandomized study, CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated, non-force sensing RF, alone.

Safety and feasibility of cardiac electrophysiology procedures in ambulatory surgery centers.

BACKGROUND: Despite their improved safety, by and large, cardiac electrophysiology procedures including catheter ablation (CA), are presently performed in hospital outpatient departments. OBJECTIVE: This large multicenter study investigated the safety and outcomes associated with various cardiac electrophysiology procedures performed at 6 ambulatory surgery centers (ASCs), primarily during the coronavirus disease 2019 pandemic under the Center for Medicare and Medicaid Services Hospitals Without Walls program. METHODS: We retrospectively analyzed the outcomes from consecutive electrophysiology procedures performed in ASCs with same-day discharge, including transesophageal echocardiography, cardioversion, cardiac implantable electronic device (CIED) implantation, electrophysiology studies, and CA for atrial fibrillation (AF), atrial flutter (AFL)/supraventricular tachycardia, ventricular premature complexes (VPCs), and atrioventricular node. RESULTS: Altogether, 4037 procedures were performed, including 779 transesophageal echocardiography/cardioversion procedures (19.3%), 1453 CIED implantation procedures (36.0%), 26 electrophysiology studies (0.6%), and 1779 CA procedures (44.1%) for AF (75.4%), AFL/supraventricular tachycardia (18.8%), VPC (4.7%), and atrioventricular node (1.1%). Overall, 80.2% of CA procedures were for left-sided atrial arrhythmias (AF/atypical AFL) requiring transseptal catheterization. Left-sided VPC ablation procedures (42.2%) were performed using a transseptal/retrograde approach. Adverse event rates were low, but comparable between CIED implantation and CA (0.76% vs 0.73%; P = .93), as were the incidences of urgent/unplanned postprocedure hospitalization (0.48% vs 0.45%; P = .89), respectively. Moreover, the adverse event rates in ASCs vs hospital outpatient departments did not differ for CIED (0.76% vs 0.65%; P = .71) or CA (0.73% vs 0.80%; P = .79). CONCLUSION: The results from this large multicenter study suggest that ASCs represent a safe and effective setting to perform a variety of cardiac electrophysiology procedures including CA. These findings bear important implications for healthcare delivery and policy.

Percutaneous endocardial occlusion of incompletely surgically ligated left atrial appendage.

INTRODUCTION: Surgical ligation of the left atrial appendage is considered standard of care in patients who undergo mitral valve surgery or as an adjunct to a surgical Maze procedure for treatment of atrial fibrillation (AF). However, several studies have demonstrated that this can result in incompletely surgically ligated left atrial appendage (ISLL) in a significant number of patients. It is believed that ISLL may in turn promote thrombus formation and lead to clinically relevant thromboembolic events. A novel approach for percutaneous endocardial occlusion of ISLL is described. METHODS AND RESULTS: Seven patients with AF and ISLL following prior open-chest, surgical suture ligation in the absence of rheumatic heart disease, underwent percutaneous endocardial ISLL occlusion using an Amplatzer Septal Occluder device guided by fluoroscopy and transesophageal echocardiography through a novel approach. Three patients were diagnosed in the setting of acute embolic stroke, 2 at the time of cardiac arrhythmia ablation and 2 by elective precardioversion transesophageal echocardiography. All patients were treated with oral anticoagulation therapy. Acute and long-term ISLL occlusion was successfully achieved in 6 patients, in whom oral anticoagulation was eventually discontinued without any embolic events during 10 ± 2 months of follow-up. CONCLUSION: Percutaneous endocardial occlusion of ISLL is feasible using an Amplatzer Septal Occluder device. Additional studies are required to evaluate the long-term safety and efficacy of this therapeutic treatment strategy in patients with ISLL.

Three-dimensional mapping, recording and ablation in simulated and induced ventricular tachyarrhythmias during mechanical circulatory support using the percutaneous heart pump.

PURPOSE: Due to their internal rotating magnets, conventional impeller-driven percutaneous ventricular assist devices (PVADs) yield high-frequency electrogram artifact and electromagnetic interference (EMI) when used with magnetic-based 3D electroanatomic mapping systems. The new percutaneous heart pump (PHP; Abbott, Chicago, IL) is a 14-French, 5-L/min, impeller axial-flow PVAD with a novel design that utilizes an external motor. METHODS: We evaluated the feasibility of 3D mapping and radiofrequency ablation (RFA) in vivo during PHP mechanical circulatory support (MCS) in simulated ventricular tachycardia (pacing at 300 ms) and ventricular flutter (VFL, pacing at 200 ms) and also during ventricular fibrillation (VF) in a porcine model. Anterograde (right ventricular), transseptal, retrograde, and epicardial right and left ventricular 3D mapping (EnSite/CARTO) and RFA were performed in 6 swine using high-density mapping and force-sensing RFA catheters (TactiCath/ThermoCool). Surface and intracardiac electrograms and 3D maps were analyzed for noise/interference with and without MCS using PHP in sinus rhythm and simulated VT/VFL and VF. RESULTS: Mapping and RFA proved feasible in the presence of MCS using PHP. The mean arterial pressure in sinus rhythm was 55 ± 2 mmHg (baseline) and 84 ± 4 mmHg during MCS with PHP and well-maintained during simulated VT (73 ± 8 mmHg) and VFL (65 ± 2 mmHg) and even in VF (65 ± 5 mmHg). No electrogram noise/artifact, EMI, or 3D map distortions were observed during mapping/RFA with either of two mapping systems. CONCLUSIONS: Endocardial and epicardial 3D mapping and RFA in the presence of PHP are feasible and offer significant MCS during simulated VT/VFL and VF. Furthermore, PHP yielded no electrogram noise/artifact, EMI, or 3D mapping distortions in conjunction with magnetic-based 3D mapping systems.

Pulmonary Vein Isolation With and Without Posterior Wall Isolation in Paroxysmal Atrial Fibrillation: IMPPROVE-PAF Trial.

BACKGROUND: Prior studies have demonstrated clinical benefits associated with cryoballoon pulmonary vein isolation (PVI) and concomitant posterior wall isolation (PWI) in patients with persistent atrial fibrillation (AF). However, the role for this approach in patients with paroxysmal atrial fibrillation (PAF) remains unclear. OBJECTIVES: This study investigated the acute and long-term outcomes of PVI vs PVI+PWI using cryoballoon in patients with symptomatic PAF. METHODS: This retrospective study (NCT05296824) examined the outcomes of cryoballoon PVI (n = 1,342) vs cryoballoon PVI+PWI (n = 442) in patients with symptomatic PAF during long-term follow-up. Using the nearest-neighbor method, a 1:1 matched sample of patients receiving PVI alone and PVI+PWI was created. RESULTS: The matched cohort consisted of 320 patients (PVI: n = 160; PVI+PWI: n = 160). PVI+PWI was associated with longer cryoablation (23 ± 10 minutes vs 42 ± 11 minutes; P < 0.001) and procedure times (103 ± 24 minutes vs 127 ± 14 minutes; P < 0.001). In 39 (24.4%) of 160 patients, adjunct radiofrequency ablation was required for PVI+PWI. Adverse event rates were similar (PVI 3.8% vs PVI+PWI 1.9%; P = 0.31). Though there were no differences at 12 months, freedom from all atrial arrhythmias (67.5% vs 45.0%; P < 0.001) and AF (75.6% vs 55.0%; P < 0.001) were significantly greater with PVI+PWI vs PVI alone at 39 ± 9 months of follow-up. PVI+PWI was also associated with reduced long-term need for cardioversion (16.9% vs 27.5%; P = 0.02) and repeat catheter ablation (11.9% vs 26.3%; P = 0.001), and emerged as the only significant predictor of freedom from recurrent AF (HR: 2.79; 95% CI: 1.64-4.74; P < 0.001). CONCLUSIONS: Compared with cryoballoon PVI, cryoballoon PVI+PWI appears to be associated with greater freedom from recurrent atrial arrhythmias and AF in patients with PAF during long-term follow-up >3 years.

Concomitant Pulmonary Vein and Posterior Wall Isolation Using Cryoballoon With Adjunct Radiofrequency in Persistent Atrial Fibrillation.

OBJECTIVES: The aim of this multicenter, randomized, single-blind study was to prospectively evaluate the short-and long-term outcomes of pulmonary vein isolation (PVI) versus PVI with concomitant left atrial posterior wall isolation (PWI) using the cryoballoon in patients with symptomatic persistent/long-standing persistent atrial fibrillation (P/LSP-AF). BACKGROUND: Some studies have suggested a clinical benefit associated with PVI+PWI in patients with P/LSP-AF. However, there are limited safety and efficacy data on this approach using cryoballoon ablation. METHODS: The immediate and long-term outcomes in patients with P/LSP-AF randomized to PVI (n = 55) versus PVI+PWI (n = 55) using the cryoballoon were prospectively examined. RESULTS: Baseline characteristics were similar. PVI was achieved in all patients (21 ± 11 min). PWI was attained using 23 ± 8 min of cryoablation. Adjunct radiofrequency ablation was required in 4 of 110 patients (7.3%) to complete PVI (3 ± 2 min) and in 25 of 55 patients (45.5%) to complete PWI (4 ± 6 min). Although left atrial dwell time (113 ± 31 min vs. 75 ± 32 min; p < 0.001) and total procedure time (168 ± 34 min vs. 127 ± 40 min; p < 0.001) were longer with PVI+PWI, this cohort required fewer intraprocedural cardioversions (89.1% vs. 96.4%; p = 0.04). Adverse events occurred in 5.5% in each group (p = 1.00). However, the incidence of recurrent atrial fibrillation at 12 months was significantly lower with PVI+PWI (25.5% vs. 45.5%; p = 0.028). Additionally, in a multivariate analysis, PVI+PWI emerged as a significant predictor of freedom from recurrent atrial fibrillation (odds ratio: 3.67; 95% confidence interval: 1.44 to 9.34; p = 0.006). CONCLUSIONS: In patients with P/LSP-AF, PVI+PWI using the cryoballoon is associated with a significant reduction in atrial fibrillation recurrence, but similar safety, as compared with PVI alone.

Long-term durability of posterior wall isolation using the cryoballoon in patients with persistent atrial fibrillation: a multicenter analysis of repeat catheter ablations.

PURPOSE: There is a growing interest in performing pulmonary vein isolation (PVI) with concomitant posterior wall isolation (PWI) using the cryoballoon for the treatment of patients with persistent atrial fibrillation (AF). However, there is little known about the long-term durability of PWI using this approach. METHODS: In this multicenter study, we retrospectively examined the durability of PVI + PWI using the 28-mm cryoballoon by investigating the outcomes from consecutive patients referred for repeat catheter ablation. RESULTS: Altogether, 81/519 patients (15.6%) were referred for repeat catheter ablation. Repeat ablation was associated with a longer AF duration, hypertension, heart failure, multiple cardioversions, and antiarrhythmic therapy as well as larger left atrial (LA) diameters (49 ± 4 mm versus 43 ± 5 mm; P < 0.001) and greater need for "touch-up" (adjunct) radiofrequency ablation (44.4% versus 18.3%; P < 0.001). LA diameter also emerged as a significant predictor for adjunct radiofrequency ablation (P < 0.001). Durable PVI was observed in 66/81 patients (81.5%) and PWI in 67/81 patients (82.7%). Those with incomplete PWI exhibited larger LA diameters, particularly > 48 mm (negative predictive value = 89.7%). Lastly, an atypical LA posterior wall/roof flutter represented the third most common cause of arrhythmia recurrence and essentially every patient with incomplete PWI exhibited such an arrhythmia. CONCLUSION: PWI performed using a 28-mm cryoballoon in conjunction with PVI exhibits long-term durability in the vast majority of patients with persistent AF. While LA diameter (particularly > 48 mm) is a significant predictor for the need for adjunct radiofrequency ablation when performing this technique, those with incomplete PWI invariably present with an atypical flutter using this substrate.

Venous Vascular Closure System Versus Manual Compression Following Multiple Access Electrophysiology Procedures: The AMBULATE Trial.

OBJECTIVES: This study compared the efficacy and safety of the VASCADE MVP Venous Vascular Closure System (VVCS) device (Cardiva Medical, Santa Clara, California) to manual compression (MC) for closing multiple access sites after catheter-based electrophysiology procedures. BACKGROUND: The VASCADE MVP VVCS is designed to provide earlier ambulatory hemostasis than MC after catheter-based procedures. METHODS: The AMBULATE (A Randomized, Multi-center Trial to Compare Cardiva Mid-Bore [VASCADE MVP] VVCS to Manual Compression in Closure of Multiple Femoral Venous Access Sites in 6 - 12 Fr Sheath Sizes) trial was a multicenter, randomized trial of device closure versus MC in patients who underwent ablation. Outcomes included time to ambulation (TTA), total post-procedure time (TPPT), time to discharge eligibility (TTDe), time to hemostasis (TTH), 30-day major and minor complications, pain medication usage, and patient-reported outcomes. RESULTS: A total of 204 patients at 13 sites were randomized to the device arm (n = 100; 369 access sites) or the MC arm (n = 104; 382 access sites). Baseline characteristics were similar between groups. Mean TTA, TPPT, TTDe, and TTH were substantially lower in the device arm (respective decreases of 54%, 54%, 52%, and 55%; all p < 0.0001). Opioid use was reduced by 58% (p = 0.001). There were no major access site complications. Incidence of minor complications was 1.0% for the device arm and 2.4% for the MC arm (p = 0.45). Patient satisfaction scores with duration of and comfort during bedrest were 63% and 36% higher in device group (both p < 0.0001). Satisfaction with bedrest pain was 25% higher (p = 0.001) for the device overall, and 40% higher (p = 0.002) for patients with a previous ablation. CONCLUSIONS: Use of the closure device for multiple access ablation procedures resulted in significant reductions in TTA, TPPT, TTH, TTDe, and opioid use, with increased patient satisfaction and no increase in complications. (A Randomized, Multi-center Trial to Compare Cardiva Mid-Bore VVCS to Manual Compression in Closure of Multiple Femoral Venous Access Sites in 6 - 12 Fr Sheath Sizes [AMBULATE]; NCT03193021).

All is not lost, when lead goes in the wrong direction.

Left sided superior vena cava (SVC) is an uncommon anomaly noted in the general population. It adds complexity to the procedure, when attempting to place pacing or defibrillator devices into the heart. Here we report a case where the leads were placed through the left sided SVC into the right sided chambers giving an interesting X-ray appearance.

Verification of a novel atrial fibrillation cryoablation dosing algorithm guided by time-to-pulmonary vein isolation: Results from the Cryo-DOSING Study (Cryoballoon-ablation DOSING Based on the Assessment of Time-to-Effect and Pulmonary Vein Isolation Guidance).

BACKGROUND: There are no recommendations on the optimal dosing for cryoablation of atrial fibrillation (Cryo-AF). OBJECTIVE: The purpose of this study was to develop and prospectively test a Cryo-AF dosing protocol guided exclusively by time-to-pulmonary vein (PV) isolation (TT-PVI) in patients undergoing a first-time Cryo-AF. METHODS: In this multicenter study, we examined the acute/long-term safety/efficacy of Cryo-AF using the proposed dosing algorithm (Cryo-AFDosing; n = 355) against a conventional, nonstandardized approach (Cryo-AFConventional; n = 400) in a nonrandomized fashion. RESULTS: Acute PV isolation was achieved in 98.9% of patients in Cryo-AFDosing (TT-PVI = 48 ± 16 seconds) vs 97.2% in Cryo-AFConventional (P = .18). Cryo-AFDosing was associated with shorter (149 ± 34 seconds vs 226 ± 46 seconds; P <.001) and fewer (1.7 ± 0.8 vs 2.9 ± 0.8; P <.001) cryoapplications, reduced overall ablation (16 ± 5 minutes vs 40 ± 14 minutes; P <.001), fluoroscopy time (13 ± 6 minutes vs 29 ± 13 minutes; P <.001), left atrial dwell time (51 ± 14 minutes vs 118 ± 25 minutes; P <.001), and total procedure time (84 ± 23 minutes vs 145 ± 49 minutes; P <.001) but similar nadir balloon temperature (-47°C ± 8°C vs -48°C ± 6°C; P = .41) and total thaw time (43 ± 27 seconds vs 45 ± 19 seconds; P = .09) as compared to Cryo-AFConventional. Adverse events (2.0% vs 2.7%; P = .48), including persistent phrenic nerve palsy (0.6% vs 1.2%; P = .33) and 12-month freedom from all atrial arrhythmias (82.5% vs 78.3%; P = .14), were similar between Cryo-AFDosing and Cryo-AFConventional. However, Cryo-AFDosing was specifically associated with fewer atypical atrial flutters/tachycardias during long-term follow-up (8.5% vs 13.5%; P = .02) as well as fewer late PV reconnections at redo procedures (5.0% vs 18.5%; P <.001). CONCLUSION: A novel Cryo-AF dosing algorithm guided by TT-PVI can help individualize the ablation strategy and yield improved procedural endpoints and efficiency as compared to a conventional, nonstandardized approach.

Impact of irrigation flow rate and intrapericardial fluid on cooled-tip epicardial radiofrequency ablation.

BACKGROUND: The optimal irrigation flow rate (IFR) during epicardial radiofrequency (RF) ablation has not been established. OBJECTIVE: This study specifically examined the impact of IFR and intrapericardial fluid (IPF) accumulation during epicardial RF ablation. METHODS: Altogether, 452 ex vivo RF applications (10 g for 60 seconds) delivered to the epicardial surface of bovine myocardium using 3 open-irrigated ablation catheters (ThermoCool SmartTouch, ThermoCool SmartTouch-SF, and FlexAbility) and 50 in vivo RF applications delivered (ThermoCool SmartTouch-SF) in 4 healthy adult swine in the presence or absence of IPF were examined. Ex vivo, RF was delivered at low (≤3 mL/min), reduced (5-7 mL/min), and high (≥10 mL/min) IFRs using intermediate (25-35 W) and high (35-45 W) power. In vivo, applications were delivered (at 9.3 ± 2.2 g for 60 seconds at 39 W) using reduced (5 mL/min) and high (15 mL/min) IFRs. RESULTS: Ex vivo, surface lesion diameter inversely correlated with IFR, whereas maximum lesion diameter and depth did not differ. While steam pops occurred more frequently at low IFR using high power (ThermoCool SmartTouch and ThermoCool SmartTouch-SF), tissue disruption was rare and did not vary with IFR. In vivo, charring/steam pop was not detected. Although there were no discernible differences in lesion size with IFR, surface lesion diameter, maximum diameter, depth, and volume were all smaller in the presence of IPF at both IFRs. CONCLUSION: Cooled-tip epicardial RF ablation created using reduced IFRs (5-7 mL/min) yields lesion sizes similar to those created using high IFRs (≥10 mL/min) without an increase in steam pop/tissue disruption, whereas the presence of IPF significantly reduces the lesion size.