Impact of Contact Force on Pulsed Field Ablation Outcomes Using Focal Point Catheter.

BACKGROUND: Conventional focal radiofrequency catheters may be modified to enable multiple energy modalities (radiofrequency or pulsed field [PF]) with the benefit of contact force (CF) feedback, providing greater flexibility in the treatment of arrhythmias. Information on the impact of CF on lesion formation in PF ablations remains limited. METHODS: An in vivo study was performed with 8 swine using an investigational dual-energy CF focal catheter with local impedance. Experiment I: To evaluate atrial lesion formation, contiguity, and width, a point-by-point approach was used to create an intercaval line. The distance between the points was prespecified at 4±1 mm. Half of the line was created with radiofrequency energy, whereas the other half utilized PF (single 2.0 kV application with a proprietary waveform). Experiment II: To evaluate single application lesion dimensions with a proprietary waveform, discrete ventricular lesions were performed with PFA (single 2.0 kV application) with targeted levels of CF: low, 5 to 15 g; medium, 20 to 30 g; and high, 35 to 45 g. Following 1 week of survival, animals underwent endocardial/epicardial remapping, and euthanasia to enable histopathologic examination. RESULTS: Experiment I: Both energy modalities resulted in a complete intercaval line of transmural ablation. PF resulted in significantly wider lines than radiofrequency: minimum width, 14.9±2.3 versus 5.0±1.6 mm; maximum width, 21.8±3.4 versus 7.3±2.1 mm, respectively; P<0.01 for each. Histology confirmed transmural lesions with both modalities. Experiment II: With PF, lesion depth, width, and volume were larger with higher degrees of CF (depth: r=0.82, P<0.001; width: r=0.26, P=0.052; and volume: r=0.55, P<0.001), with depth increasing at a faster rate than width. The mean depths were as follows: low (n=17), 4.3±1.0 mm; medium (n=26), 6.4±1.2 mm; and high (n=14), 9.1±1.4 mm. CONCLUSIONS: Using the same focal point CF-sensing catheter, a novel PF ablation waveform with a single application resulted in transmural atrial lesions that were significantly wider than radiofrequency. Lesion depth showed a significant positive correlation with CF with depths of 6.4 mm at moderate CF.

Cryoballoon pulmonary vein isolation versus radiofrequency ablation of the pulmonary veins and left atrial posterior wall: Patient-reported outcomes.

BACKGROUND: Data are lacking on patient-reported outcomes (PRO) following cryoballoon ablation (CBA) versus radiofrequency ablation (RFA). We sought to evaluate QoL and clinical outcomes of cryoballoon pulmonary vein isolation only (CRYO-PVI-ONLY) versus RFA with PVI and posterior wall isolation (RF-PVI+PWI) in a large prospective PRO registry. METHODS: Patients who underwent AF ablation (2013-2016) at our institution were enrolled in an automated, prospectively maintained PRO registry. CRYO-PVI-ONLY patients were matched (1:1) with RF-PVI+PWI patients based on age, gender, and type of AF (paroxysmal vs. persistent). QoL and clinical outcomes were assessed using PRO surveys at baseline and at 1-year. The atrial fibrillation symptom severity scale (AFSSS) was the measure for QoL. Additionally, we assessed patient-reported clinical improvement, arrhythmia recurrence, and AF burden (as indicated by AF frequency and duration scores). RESULTS: A total of 296 patients were included (148 in each group, 72% paroxysmal). By PRO, a significant improvement in QoL was observed in the overall study population and was comparable between CRYO-PVI-ONLY and RF-PVI+PWI (baseline median AFSSS of 11.5 and 11; reduced to 2 and 4 at 1 year, respectively; p = 0.44). Similarly, the proportion of patients who reported improvement in their overall QoL and AF related symptoms was high and similar between the study groups [92% (CRYO-PVI-ONLY) vs. 92.8% (RF-PVI+PWI); p = 0.88]. Arrhythmia recurrence was significantly more common in the CRYO-PVI-ONLY group (39.7%) compared to RF-PVI+PWI (27.7 %); p = 0.03. Comparable results were observed in paroxysmal and persistent AF. CONCLUSION: CRYO-PVI-ONLY and RF-PVI+PWI resulted in comparable improvements in patient reported outcomes including QoL and AF burden; with RF-PVI+PWI being more effective at reducing recurrences.

Thirty-day readmission after catheter ablation for ventricular tachycardia: associated factors and outcomes.

BACKGROUND: Patients with ventricular tachycardia (VT) who require VT ablation are at high risk for readmission. This study aimed to identify the causes and outcomes of 30-day readmission after VT ablation and to analyze the predictors of recurrent VT that required rehospitalization. METHODS: Using the Nationwide Readmission Database, our study included patients aged ≥ 18 years who underwent VT catheter ablation between 2017 and 2020. Based on the International Classification of Diseases, Tenth Revision, Clinical Modification (ICD-10-CM), we identified the causes of 30-day readmission by organ systems and analyzed their outcomes. Additional analysis was performed to determine the independent predictors of 30-day readmission for recurrent VT. RESULTS: Of the 4228 patients who underwent VT ablation, 14.2% were readmitted within 30 days of the procedure. The most common cause of readmission was cardiac events (73.6%). Among the cardiac-related readmissions, recurrent VT (47.7%) and congestive heart failure (CHF) (12.9%) were the most common etiologies. Among the readmissions, patients readmitted for CHF had the highest rate of readmission mortality (9.2%). Of the patients readmitted within 30 days of the procedure, 278 patients (6.8%) were readmitted for recurrent VT. Via multivariable analysis, CHF (OR: 1.97; 95% CI: 1.12-3.47; P = 0.02) and non-elective index admissions (OR: 1.63; 95% CI: 1.04-2.55; P = 0.03) were identified as the independent predictors predictive of 30-day readmissions for recurrent VT. CONCLUSIONS: Recurrent VT was the most common cause of readmission after the VT ablation procedure, and CHF and non-elective index admissions were the significant predictors of these early readmissions. Readmission due to CHF had the highest mortality rate during readmission.

Efficacy of Pulsed Field vs Radiofrequency for the Reablation of Chronic Radiofrequency Ablation Substrate: Redo Pulsed Field Ablation.

BACKGROUND: The efficacy of pulsed field ablation (PFA) for redo procedures is unknown. OBJECTIVES: In this study, the authors aimed to evaluate the effectiveness of PFA when performing PFA over chronic RFA (redo environment). METHODS: This was a 3-step in vivo study. In step 1 (creation of redo environment), 6 swine underwent radiofrequency ablation (RFA) with a local impedance measuring catheter and a contact force-enabled catheter in 3 different sites: the right atrium (RA) (intercaval line with intentional gaps), the left atrium (LA) (pulmonary vein isolation [PVI] with intentional gaps and superficial posterior wall ablations), and the left ventricle (LV) (short RFA applications [chronic RFA]). In step 2 (re-ablation), following a survival period of ≈5 weeks, animals were retreated as follows: in the RA, a focal PFA catheter over the prior intercaval line; in the LA, PVI using a pentaspline PFA catheter; and in the LV, animals were randomized to focal PFA or RFA. In each arm, 2 types of lesions were performed: acute or acute over chronic. In step 3 (remapping and euthanization), following an additional 3 to 5 days, all animals were remapped and sacrificed. RESULTS: In the RA, re-ablation with PFA resulted in a complete intercaval block in all animals, expanding and homogenizing the disparate chronic RFA lesions from a width of 4 to 7 mm (chronic RFA) to a width of 16 to 28 mm (PFA over chronic RFA). In the LA, re-ablation with PFA resulted in complete PVI and transmural ablation of the PW. In the LV, the mean depth for acute RFA (post 2-5 days survival) was 7.6 ± 1.3 mm vs 3.9 ± 1.6 mm in the acute over chronic RFA lesions (P < 0.01). In contrast, the mean depth for acute PFA was 7.0 ± 1.6 mm, similar to when ablating with PFA over RFA (7.1 ± 1.3 mm; P = 0.94). CONCLUSIONS: PFA is highly efficient for ablation following prior RFA, which may be beneficial in patients presenting for redo procedures. In the ventricle, PFA resulted in lesions that are deeper than RFA when ablating over chronic superficial RFA lesions.

Effects of Contact Force on Lesion Size During Pulsed Field Catheter Ablation: Histochemical Characterization of Ventricular Lesion Boundaries.

BACKGROUND: Effects of contact force (CF) on lesion formation during pulsed field ablation (PFA) have not been well validated. The purpose of this study was to determine the relationship between average CF and lesion size during PFA using a swine-beating heart model. METHODS: A 7F catheter with a 3.5-mm ablation electrode and CF sensor (TactiCath SE, Abbott) was connected to a PFA system (CENTAURI, Galvanize Therapeutics). In 5 closed-chest swine, biphasic PFA current was delivered between the ablation electrode and a skin patch at 40 separate sites in right ventricle (28 Amp) and 55 separate sites in left ventricle (35 Amp) with 4 different levels of CF: (1) low (CF range of 4-13 g; median, 9.5 g); (2) moderate (15-30 g; median, 21.5 g); (3) high (34-55 g; median, 40 g); and (4) no electrode contact, 2 mm away from the endocardium. Swine were sacrificed at 2 hours after ablation, and lesion size was measured using triphenyl tetrazolium chloride staining. In 1 additional swine, COX (cytochrome c oxidase) staining was performed to examine mitochondrial activity to delineate reversible and irreversible lesion boundaries. Histological examination was performed with hematoxylin and eosin and Masson trichrome staining. RESULTS: Ablation lesions were well demarcated with triphenyl tetrazolium chloride staining, showing (1) a dark central zone (contraction band necrosis and hemorrhage); (2) a pale zone (no mitochondrial activity and nuclear pyknosis, indicating apoptosis zone); and a hyperstained zone by triphenyl tetrazolium chloride and COX staining (unaffected normal myocardium with preserved mitochondrial activity, consistent with reversible zone). At constant PFA current intensity, lesion depth increased significantly with increasing CF. There were no detectable lesions resulting from ablation without electrode contact. CONCLUSIONS: Acute PFA ventricular lesions show irreversible and reversible lesion boundaries by triphenyl tetrazolium chloride staining. Electrode-tissue contact is required for effective lesion formation during PFA. At the same PFA dose, lesion depth increases significantly with increasing CF.

Catheter ablation of atrial fibrillation in elderly and very elderly patients: safety, outcomes, and quality of life.

BACKGROUND: Atrial fibrillation (AF) risk increases with age. We aim to assess the efficacy and safety of catheter ablation in the older population. METHODS: All patients undergoing AF ablation (2013-2021) at our institution were enrolled in a prospectively maintained registry. The primary endpoint was AF recurrence. Patients were divided into 3 groups: non-elderly (< 65 years), elderly (65-75 years), and very elderly (> 75 years). Patient surveys at baseline and during follow-up were used to calculate quality of life (QoL) metrics: the AF severity score as well as the AF burden. RESULTS: A total of 7020 patients were included (42% non-elderly, 42% elderly, and 16% very elderly). Periprocedural major complications were low (< 1.5%) and similar in all groups besides pericardial effusion which was more frequent with older age and similar between the elderly and very elderly. At 3 years, AF recurrence for persistent AF (PersAF) was highest in the very elderly group (48%), followed by the elderly group (42%), and was the lowest in the non-elderly group (36%). In paroxysmal AF (PAF), there was no difference in AF recurrence between the elderly and non-elderly, while the very elderly remained associated with a significantly increased risk. Multivariable Cox analysis confirmed these findings (PersAF; elderly: HR = 1.23, P = 0.003; very elderly: HR = 1.44, P < 0.001) (PAF; elderly: HR = 1.04, P = 0.62; very elderly: HR = 1.30, P = 0.01). Catheter ablation resulted in a significant improvement in quality of life, irrespective of age group. CONCLUSION: Catheter ablation in elderly and very elderly patients is safe, efficacious, and associated with QoL benefits. Overall, major complications were minimal and did not differ significantly between age groups, with the exception of pericardial effusions which were higher in the elderly and very elderly compared to non-elderly adults. Very elderly patients had a higher rate of AF recurrence when compared with elderly or non-elderly patients. Nevertheless, ablation resulted in a remarkable improvement in QoL and a reduction of AF burden and AF symptoms with a similar magnitude, irrespective of age.

Paroxysmal atrial fibrillation ablation with a novel temperature-controlled CF-sensing catheter: Q-FFICIENCY clinical and healthcare utilization benefits.

INTRODUCTION: The prospective, nonrandomized, multicenter Q-FFICIENCY study demonstrated the safety and 12-month efficacy of paroxysmal atrial fibrillation (AF) ablation with the novel QDOT MICRO temperature-controlled, contact force-sensing, radiofrequency (RF) catheter. Participants underwent pulmonary vein isolation with very high-power short-duration (vHPSD) mode (90 W, ≤4 s) alone or combined with conventional-power temperature-controlled (CPTC) mode (25-50 W). This study aimed to assess quality-of-life (QOL) and healthcare utilization (HCU) benefits experienced by Q-FFICIENCY study participants. METHODS: Besides evaluating procedural efficiency, QOL and HCU were assessed through 12 months postablation via Atrial Fibrillation Effect on Quality-of-Life Tool (AFEQT) score, antiarrhythmic drug (AAD) use, and incidence of cardioversion and cardiovascular hospitalization. RESULTS: Of 191 participants enrolled, 166 were ablated with the new catheter. Compared to baseline, statistically significant, clinically meaningful improvements in composite and subcategories of AFEQT scores were observed at 3 months and sustained through 12 months (12-month increase, 29.3-44.2 points). Class I/III AAD use decreased from 97.6% (162/166) at baseline to 19.6% (31/158) during Months 6-12, representing a significant 79.9% reduction. The cardioversion rate significantly declined by 93.9% from 31.3% (12 months preablation) to 1.9% (evaluation period). One-year Kaplan-Meier estimates of freedom from all-cause and cardiovascular hospitalization were 80.9% (95% confidence interval [CI], 74.8%-86.9%) and 88.8% (95% CI, 84.0%-93.7%), respectively. CONCLUSIONS: Paroxysmal AF ablation with the novel temperature-controlled RF catheter in vHPSD mode, alone or with CPTC mode, led to clinically meaningful improvement in QOL and significant reduction in AAD use, cardioversion, and cardiovascular hospitalization.

Ischemic or Coronary Evaluations in Patients With Monomorphic VT Electrical Storm Undergoing VT Ablation.

BACKGROUND: Monomorphic ventricular tachycardia (VT) electrical storm (ES) in patients with coronary artery disease is dependent on scarred myocardium. The role of routine ischemic or coronary evaluations before ablation in patients presenting with monomorphic VT storm, without acute coronary syndrome (ACS), remains unknown. OBJECTIVES: This study sought to assess the impact of ischemic or coronary evaluations on procedural outcomes and post-ablation mortality in monomorphic VT storm patients. METHODS: All patients undergoing VT ablation at the Cleveland Clinic from 2014 to 2020 after presenting with monomorphic VT storm were enrolled in a prospectively maintained registry. The associations among ischemic or coronary evaluations and short-term procedural efficacy, acute outcomes, and mortality during follow-up were assessed. RESULTS: A total of 97 consecutive patients with monomorphic VT storm in the absence of ACS underwent VT ablations. This cohort was characterized by severe LV systolic dysfunction (mean left ventricular ejection fraction 30.3%, 67% with known ischemic cardiomyopathy) with moderately severe heart failure (median NYHA functional class II); 45% of patients underwent ischemic or coronary evaluations via coronary angiography (10%), noninvasive myocardial perfusion (26%), or both (9%). The yield of these evaluations was low: No acute coronary occlusions were identified. There was no association between ischemic evaluation and acute ablation outcomes or mortality during follow-up. Similarly, in a secondary analysis, the yield of ischemic or coronary evaluations in patients with monomorphic VT storm and known coronary disease (regardless of ablation status) was found to be low. CONCLUSIONS: Ischemic evaluations in patients with monomorphic VT storm without ACS may not improve procedural outcomes or mortality after ablation.

Impact of obesity on catheter ablation of atrial fibrillation: Patient characteristics, procedural complications, outcomes, and quality of life.

INTRODUCTION: Obesity is a well-known risk factor for atrial fibrillation (AF). We aim to evaluate the effect of baseline obesity on procedural complications, AF recurrence, and symptoms following catheter ablation (CA). METHODS: All consecutive patients undergoing AF ablation (2013-2021) at our center were enrolled in a prospective registry. The study included all consecutive patients with available data on body mass index (BMI). Primary endpoint was AF recurrence based on electrocardiographic documentation. Patients were categorized into five groups according to their baseline BMI. Patients survey at baseline and at follow-up were used to calculate AF symptom severity score (AFSS) as well as AF burden (mean of AF duration score and AF frequency score; scale 0: no AF to 10: continuous and 9 frequencies/durations in between). Patients were scheduled for follow-up visits with 12-lead electrocardiogram at 3, 6, and 12 months after ablation, and every 6 months thereafter. RESULTS: A total of 5841 patients were included (17% normal weight, 34% overweight, 27% Class I, 13% Class II, and 9% Class III obesity). Major procedural complications were low (1.5%) among all BMI subgroups. At 3 years AF recurrence was the highest in Class III obesity patients (48%) followed by Class II (43%), whereas Class I, normal, and overweight had similar results with lower recurrence (35%). In multivariable analyses, Class III obesity (BMI ≥ 40) was independently associated with increased risk for AF recurrence (hazard ratio, 1.30; confidence interval, 1.06-1.60; p = .01), whereas other groups had similar risk in comparison to normal weight. Baseline AFSS was lowest in normal weight, and highest in Obesity-III, median (interquartile range) 10 (5-16) versus 15 (10-21). In all groups, CA resulted in a significant improvement in their AFSS with a similar magnitude among the groups. At follow-up, AF burden was minimal and did not differ significantly between the groups. CONCLUSION: AF ablation is safe with a low complication rate across all BMI groups. Morbid obesity (BMI ≥ 40) was significantly associated with reduced AF ablation success. However, ablation resulted in improvement in QoL including reduction of the AFSS, and AF burden regardless of BMI.

Catheter-Based Electroporation: A Novel Technique for Catheter Ablation of Cardiac Arrhythmias.

Catheter ablation of arrhythmias is now standard of care in invasive electrophysiology. Current ablation strategies are based on the use of thermal energy. With continuous efforts to optimize thermal energy delivery, effectiveness has greatly improved; however, safety concerns persist. This review focuses on a novel ablation technology, irreversible electroporation (IRE), also known as pulsed-field ablation which may be a safer alternative for arrhythmia management. Pulsed-field ablation is thought to be a nonthermal ablation that applies short-duration high-voltage electrical fields to ablate myocardial tissue with high selectivity and durability while sparing important neighboring structures such as the esophagus and phrenic nerves. There are multiple ongoing studies investigating the potential superior outcomes of IRE compared to radiofrequency ablation in treating patients with atrial and ventricular arrhythmias. In this review, we describe the current evidence of preclinical and clinical trials that have shown promising results of catheter-based IRE.

Atrial Fibrillation Ablation in Young Adults: Measuring Quality of Life Using Patient-Reported Outcomes Over 5 Years.

BACKGROUND: Ablation is used for both rhythm control and improved quality of life (QoL) in atrial fibrillation (AF). It has been suggested that young adults may experience high recurrence rates after ablation and data remain lacking regarding QoL benefits. We aimed to investigate AF ablation outcomes and QoL benefits in young adults undergoing AF ablation using a large prospectively maintained registry and automated patient-reported outcomes (PRO). METHODS: All patients undergoing AF ablation (2013-2016) at our center were prospectively enrolled. Patients aged 50 years or younger were included. For PROs, QoL measures and symptoms were assessed at baseline, 3 months after ablation, and every 6 months thereafter. The AF severity score served as the main assessment of QoL. RESULTS: A total of 241 young adults (age, 16-50 years) were included (17% female, 40.3% persistent AF). In all, 77.2% of patients remained arrhythmia-free during the first year of follow-up (80% in nonstructural AF and 66% in structural AF). Using PROs, 90% of patients reported improvement in QoL throughout all survey time points up to 5 years postablation (P<0.0001). The baseline median AF severity score was 14 and improved to between 2 and 4 on all follow-up after ablation (P<0.0001). Patients also reported fewer and shorter AF episodes, fewer emergency room visits secondary to AF, and fewer hospitalizations (P<0.0001). CONCLUSIONS: Ablation remains an effective rhythm-control strategy in young adults with AF. Young adults also experience significant improvement in QoL with reduction of the frequency and duration of AF episodes and AF-related healthcare utilization.

Very High-Power Short-Duration, Temperature-Controlled Radiofrequency Ablation in Paroxysmal Atrial Fibrillation: The Prospective Multicenter Q-FFICIENCY Trial.

BACKGROUND: QDOT MICRO (QDM) is a novel contact force-sensing catheter optimized for temperature-controlled radiofrequency (RF) ablation. The very high-power short-duration (vHPSD) algorithm modulates power, maintaining target temperature during 90 W ablations for ≤4 seconds. OBJECTIVES: This study aims to evaluate safety and 12-month effectiveness of the QDM catheter in paroxysmal atrial fibrillation (AF) ablation using the vHPSD mode combined with conventional-power temperature-controlled (CPTC) mode. METHODS: In this prospective, multicenter, nonrandomized study, patients with drug-refractory, symptomatic paroxysmal AF underwent pulmonary vein (PV) isolation with QDM catheter with vHPSD as primary ablation mode, with optional use of the CPTC mode (25 to 50 W) for PV touch-up or non-PV ablation. The primary safety endpoint was incidence of primary adverse events within ≤7 days of ablation. The primary effectiveness endpoint was freedom from documented atrial tachyarrhythmia recurrence and acute procedural, repeat ablation, and antiarrhythmic drug failure. RESULTS: Of 191 enrolled participants, 166 had the catheter inserted, received RF ablation, and met eligibility criteria. Median procedural, RF application for ablating PVs, and fluoroscopy times were 132.0, 8.0, and 9.1 minutes, respectively. The primary adverse event rate was 3.6%. Imaging conducted in a subset of participants (n = 40) at 3 months did not show moderate or severe PV stenosis. The Kaplan-Meier estimated 12-month rate for primary effectiveness success was 76.7%; freedom from atrial tachyarrhythmia recurrence was 82.1%; clinical success (freedom from symptomatic recurrence) was 86.0%; and freedom from repeat ablation was 92.1%. CONCLUSIONS: Temperature-controlled paroxysmal AF ablation with the novel QDM catheter in vHPSD mode (90 W, ≤4 seconds), alone or with CPTC mode (25 to 50 W), is highly efficient and effective without compromising safety. (Evaluation of QDOT MICRO Catheter for Pulmonary Vein Isolation in Subjects With Paroxysmal Atrial Fibrillation [Q-FFICIENCY]; NCT03775512).

Impact of redo ablation for atrial fibrillation on patient-reported outcomes and quality of life.

INTRODUCTION: Catheter ablation for atrial fibrillation (AF) is frequently used for the purpose of rhythm control and improved quality of life (QoL). Although success rates are high, a significant proportion of patients require redo ablation. Data are scarce on patient-centered outcomes and QoL in patients undergoing redo AF ablation. We aimed to assess QoL and clinical outcomes using a large prospectively maintained patient-reported outcomes (PRO) registry. METHODS: All patients undergoing redo AF ablation (2013-2016) at our center were enrolled in a prospective registry for outcomes and assessed for QoL using automated PRO surveys (baseline, 3 and 6 months after ablation, every 6 months thereafter). Data were collected over 3 years of follow-up. The atrial fibrillation symptom severity scale (AFSSS) was used as the main measure for QoL. Additional variables included patient-reported improvement, AF burden, and AF-related healthcare utilization including emergency room (ER) visits and hospitalizations. RESULTS: A total of 848 patients were included (28% females, mean age 63.8, 51% persistent AF). By automated PRO, significant improvement in QoL was noted (baseline median AFSSS of 12 [5-18] and ranged between 2 and 4 on subsequent assessments; p < .0001), with ≥70%of patients reported remarkable improvement in their AF-related symptoms. The proportion of patients in AF at the time of baseline survey was 36%, and this decreased to <8% across all time points during follow-up (p < .0001). AF burden was significantly reduced (including frequency and duration of episodes; p < .0001), with an associated decrease in healthcare utilization after 6 months from the time of ablation (including ER visits and hospitalizations; p < .0001). The proportion of patients on anticoagulants or antiarrhythmics decreased on follow-up across all time points (p < .0001 for all variables). CONCLUSION: Most patients derive significant QoL benefit from redo AF ablation; with reduction of both AF burden and healthcare utilization.

Improvement in Lesion Formation with Radiofrequency Energy and Utilization of Alternate Energy Sources (Cryoablation and Pulsed Field Ablation) for Ventricular Arrhythmia Ablation.

Current ablation systems rely on thermal energy to produce ablation lesions (heating: RF, laser and ultrasound, and cooling: cryo-thermia). While thermal ablation has been proven to be effective, there are several limitations: 1) relatively long procedural times; 2) high recurrence rate of ventricular arrhythmias; and 3) excessive heating potentially leading to serious complications, including steam pop (perforation), coronary arterial injury and thrombo-embolism. Pulsed field ablation (PFA)/irreversible electroporation (IRE) offers a unique non-thermal ablation strategy which has the potential to overcome these limitations. Recent pre-clinical studies suggest that PFA/IRE might be effective and safe for the treatment of cardiac arrhythmias.

Outcomes of atrial fibrillation ablation in patients with or without silent pulmonary veins from prior ablation procedure.

INTRODUCTION: Pulmonary venous (PV) electrical recovery underlies most arrhythmia recurrences after atrial fibrillation (AF) ablation. Little is known about procedural profiles and outcomes of patients with electrically silent PVs upon redo ablation for AF. METHODS: In a prospectively maintained registry, we enrolled 838 consecutive patients (2013-2016) undergoing redo ablation procedures. Ablation procedures targeted the PVs, the PV antra, and non-PV sites at operators' discretion. Procedural profiles and clinical outcomes were assessed. The primary outcome was freedom from AF after a 3-month blanking period. The secondary outcome was improvement in quality of life. RESULTS: Most patients undergoing redo AF ablation (n = 684, 82%) had PV reconnection while the remaining 154 (18%) had electrically silent PVs. Patients with recurrent AF and electrically silent PVs were older (66 vs. 64 years, p = .02), had more prior ablation procedures (median 2 IQR 1-3 vs 1 IQR 1-2 p = .001), were more likely to have non-paroxysmal AF (62% vs. 49%, p = .004) and atrial flutter (48% vs. 29%, p = .001) and had significantly larger left atrial volumes (89 vs. 81 ml, p = .003). Patients with silent PVs underwent a more extensive non-PV ablation strategies with antral extension of prior ablation sets in addition to ablation of the roof, appendage, inferior to the right PVs, peri-mitral flutter lines, cavotricuspid isthmus lines and ablation in the coronary sinus. Upon one year of follow-up, patients with electrically silent PVs were less likely to remain free from recurrent atrial arrhythmias (64% vs. 76%, p = .008). Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life. CONCLUSION: Rhythm control with extensive ablation allowed maintenance of sinus rhythm in about two thirds of patients with silent PVs during redo AF ablation procedures. Regardless of PV reconnection status, redo ablation resulted in improvement in quality of life. This remains a challenging group of patients, highlighting the need to better understand non-PV mediated AF.

Preoperative Atrial Fibrillation and Cardiovascular Outcomes After Noncardiac Surgery.

BACKGROUND: The impact of pre-existing atrial fibrillation (AF) on outcomes after noncardiac surgery is not clear. OBJECTIVES: We aimed to study the impact of AF on the risk of adverse outcomes after noncardiac surgery in a nationwide cohort. METHODS: We identified Medicare beneficiaries admitted for noncardiac surgery from 2015 to 2019 and divided the study cohort into 2 groups: with and without AF. Noncardiac surgery was classified into vascular, thoracic, general, genitourinary, gynecological, orthopedics and neurosurgery, breast, head and neck, and transplant. We used propensity score matching on exact age, sex, race, urgency and type of surgery, revised cardiac risk index (RCRI) and CHA2DS2-VASc score, and tight caliper on other comorbidities. The study outcomes were 30-day mortality, stroke, myocardial infarction, and heart failure. We examined the incremental utility of AF in addition to RCRI to predict adverse events after noncardiac surgery. RESULTS: The study cohort included 8,635,758 patients who underwent noncardiac surgery (16.4% with AF). Patients with AF were older, more likely to be men, and had higher prevalence of comorbidities. After propensity score matching, AF was associated with higher risk of mortality (OR: 1.31; 95% CI: 1.30-1.32), heart failure (OR: 1.31; 95% CI: 1.30-1.33), and stroke (OR: 1.40; 95% CI: 1.37-1.43) and lower risk of myocardial infarction (OR: 0.81; 95% CI: 0.79-0.82). Results were consistent in subgroup analysis by sex, race, type of surgery, and all strata of RCRI and CHA2DS2-VASc score. AF improved the discriminative ability of RCRI (C-statistic 0.73 to 0.76). CONCLUSION: Pre-existing AF is independently associated with postoperative adverse outcomes after NCS.