Comparison of cerebral safety following atrial fibrillation using pulsed field and thermal ablation: Results of the Neurological Assessment Subgroup in the ADVENT Trial.

BACKGROUND: Atrial fibrillation (AF) ablation carries the risk of silent cerebral event (SCE) and silent cerebral lesion (SCL). Though "silent," these may have long-term clinical implications and are challenging to study as post-procedural MRI is not standard-of-care. OBJECTIVE: The neurological assessment subgroup (NAS) of ADVENT compared cerebral effects of pulsed field ablation (PFA) to standard-of-care thermal ablation. METHODS: The NAS included consecutive randomized PFA and thermal ablation patients who received post-procedural brain MRI 12-48 hours post-ablation. Patients with apparent SCE or SCL findings underwent a modified Rankin Scale (mRS) assessment. MRI images were subsequently reviewed by a blinded Brain Imaging Core Laboratory. RESULTS: In total, 77 patients with paroxysmal AF were enrolled at 6 centers; 71 had analyzable scans (34 PFA; 37 thermal ablation). Through individual center review, 6 PFA and 4 thermal scans were identified as SCE/SCL positive, of which, 3 PFA and 0 thermal SCE/SCL findings were confirmed by a blinded core laboratory. MRI findings revealed one patient with 2-4mm SCEs, one patient with a 3mm SCE, and one patient with 2 SCLs (5.5mm and 11mm). All mRS and NIHSS scores were 0 prior to discharge and at 90-day follow-up. There were only two neurological safety events (1 TIA (PFA) and 1 stroke (thermal) in the ADVENT study, neither of which was part of the NAS. CONCLUSIONS: The ADVENT trial provides the first prospective, randomized data on the cerebral impact of PFA and thermal ablation of AF. Incidence of SCE/SCLs following ablation in the NAS was low.

Cardioneuroablation for the management of patients with recurrent vasovagal syncope and symptomatic bradyarrhythmias: the CNA-FWRD Registry.

BACKGROUND: Cardioneuroablation has been emerging as a potential treatment alternative in appropriately selected patients with cardioinhibitory vasovagal syncope (VVS) and functional AV block (AVB). However the majority of available evidence has been derived from retrospective cohort studies performed by experienced operators. METHODS: The Cardioneuroablation for the Management of Patients with Recurrent Vasovagal Syncope and Symptomatic Bradyarrhythmias (CNA-FWRD) Registry is a multicenter prospective registry with cross-over design evaluating acute and long-term outcomes of VVS and AVB patients treated by conservative therapy and CNA. RESULTS: The study is a prospective observational registry with cross-over design for analysis of outcomes between a control group (i.e., behavioral and medical therapy only) and intervention group (Cardioneuroablation). Primary and secondary outcomes will only be assessed after enrollment in the registry. The follow-up period will be 3 years after enrollment. CONCLUSIONS: There remains a lack of prospective multicentered data for long-term outcomes comparing conservative therapy to radiofrequency CNA procedures particularly for key outcomes including recurrence of syncope, AV block, durable impact of disruption of the autonomic nervous system, and long-term complications after CNA. The CNA-FWRD registry has the potential to help fill this information gap.

Surpoint algorithm for improved guidance of ablation for ventricular tachycardia (SURFIRE-VT): A pilot study.

INTRODUCTION: The utility of ablation index (AI) to guide ventricular tachycardia (VT) ablation in patients with structural heart disease is unknown. The aim of this study was to assess procedural characteristics and clinical outcomes achieved using AI-guided strategy (target value 550) or conventional non-AI-guided parameters in patients undergoing scar-related VT ablation. METHODS: Consecutive patients (n = 103) undergoing initial VT ablation at a single center from 2017 to 2022 were evaluated. Patient groups were 1:1 propensity-matched for baseline characteristics. Single lesion characteristics for all 4707 lesions in the matched cohort (n = 74) were analyzed. The impact of ablation characteristics was assessed by linear regression and clinical outcomes were evaluated by Cox proportional hazard model. RESULTS: After propensity-matching, baseline characteristics were well-balanced between AI (n = 37) and non-AI (n = 37) groups. Lesion sets were similar (scar homogenization [41% vs. 27%; p = .34], scar dechanneling [19% vs. 8%; p = .18], core isolation [5% vs. 11%; p = .4], linear and elimination late potentials/local abnormal ventricular activities [35% vs. 44%; p = .48], epicardial mapping/ablation [11% vs. 14%; p = .73]). AI-guided strategy had 21% lower procedure duration (-47.27 min, 95% confidence interval [CI] [-81.613, -12.928]; p = .008), 49% lower radiofrequency time per lesion (-13.707 s, 95% CI [-17.86, -9.555]; p < .001), 21% lower volume of fluid administered (1664 cc [1127, 2209] vs. 2126 cc [1750, 2593]; p = .005). Total radiofrequency duration (-339 s [-24%], 95%CI [-776, 62]; p = .09) and steam pops (-155.6%, 95% CI [19.8%, -330.9%]; p = .08) were nonsignificantly lower in the AI group. Acute procedural success (95% vs. 89%; p = .7) and VT recurrence (0.97, 95% CI [0.42-2.2]; p = .93) were similar for both groups. Lesion analysis (n = 4707) demonstrated a plateau in the magnitude of impedance drops once reaching an AI of 550-600. CONCLUSION: In this pilot study, an AI-guided ablation strategy for scar-related VT resulted in shorter procedure time and average radiofrequency time per lesion with similar acute procedural and intermediate-term clinical outcomes to a non-AI-guided approach utilizing traditional ablation parameters.

SARS-CoV-2 Infection Precipitating VT Storm in Patients With Cardiac Sarcoidosis.

The authors describe 3 patients presenting with cardiac sarcoidosis (CS) flare and ventricular tachycardia (VT) storm following infection with severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2), the causative agent of COVID-19. COVID-19-related cardiac manifestations can vary and include arrythmias, myocarditis, and exacerbation of underlying cardiovascular disease. The exact mechanism of myocardial involvement is not clear but may include abnormal host immune response and direct myocardial injury, thereby predisposing to enhanced arrhythmic risk. Arrhythmias account for 20% of COVID-19-related complications with ventricular arrythmias occurring in 5.9% of cases. Further studies are needed to better understand mechanisms underlying the intersection between COVID-19 infection and inflammatory cardiomyopathies.

Solving the Reach Problem: A Review of Present and Future Approaches for Addressing Ventricular Arrhythmias Arising from Deep Substrate.

Ventricular tachycardia (VT) is a significant cause of morbidity and mortality in patients with ischaemic and non-ischaemic cardiomyopathies. In most patients, the primary strategy of VT catheter ablation is based on the identification of critical components of reentry circuits and modification of abnormal substrate which can initiate reentry. Despite technological advancements in catheter design and improved ability to localise abnormal substrates, putative circuits and site of origins of ventricular arrhythmias (VAs), current technologies remain inadequate and durable success may be elusive when the critical substrate is deep or near to critical structures that are at risk of collateral damage. In this article, we review the available and potential future non-surgical investigational approaches for treatment of VAs and discuss the viability of these modalities.

inHEART Models software - novel 3D cardiac modeling solution.

INTRODUCTION: Advanced cardiac imaging is an important component in pre-procedural planning for ventricular tachycardia (VT) ablations. inHEART's proprietary software, inHEART Models, and its academic version, Multimodality Platform for Specific Imaging in Cardiology (MUSIC), provide detailed characterization of anatomical structures and scars. AREAS COVERED: This review highlights the current overview of the market and offers insight into inHEART Models and MUSIC and its application during VT ablations with supporting case examples. An overview of the clinical profile and regulatory status of inHEART Models, and other competing technologies, such as Automatic Detection of Arrhythmia Substrate (ADAS) 3D software and Catheter Precision's View into Ventricular Onset (VIVO), are also discussed. EXPERT OPINION: inHEART and MUSIC utilization has increased over the last few years and continues to establish its presence as an important aspect of VT ablations. Its unique proprietary software sets itself apart from others in the field. The introduction of dual source-photon counting detector computed tomography (PCD-CT) is expected to make significant advancements in the field and take imaging to a new level. inHEART's continued research in cardiac imaging and digital technology is expected to increase as is its global presence in the electrophysiology (EP) community.

Lower-adherence direct oral anticoagulant use is associated with increased risk of thromboembolic events than warfarin.

BACKGROUND: Real-world data have suggested inconsistent adherence to oral anticoagulation for thromboembolic event (TE) prevention in patients with Non valvular atrial fibrillation (NVAF), yet it remains unclear if event risk is elevated during gaps of non-adherence. OBJECTIVE: To compare difference in outcomes between direct oral anticoagulant (DOAC) and warfarin based on adherence to the therapy in patients with NVAF. METHODS: Using the MarketScan claims data, patients receiving prescription of warfarin or a DOAC for NVAF from January 2015 to June 2016 were included. Outcomes included hospitalization for TE (ischemic stroke or systemic embolism), hemorrhagic stroke, stroke of any kind, and major bleeding. Event rates were reported for warfarin and DOACs at a higher-adherence proportion of days covered (PDC > 80%) and lower-adherence (PDC 40-80%). RESULTS: The cohort included 83,168 patients prescribed warfarin (51% [n = 42,639]) or DOAC (49% [n = 40,529]). Lower adherence occurred in 36% (n = 15,330) of patients prescribed warfarin and 26% (n = 10,956) prescribed DOAC. As compared to higher-adherence warfarin after multivariable adjustment, the risk of TE was highest in lower-adherence DOAC (HR 1.26; 95% CI, 1.14-1.33), and lowest in higher-adherence DOAC (HR, 0.93; 95% CI, 0.88-0.99). There was a significantly higher risk of hemorrhagic stroke and stroke of any kind in the lower-adherence groups. Major bleeding was more common with lower-adherence DOAC (HR, 1.43, 95% CI, 1.35-1.52) and lower-adherence warfarin (HR, 1.32, 95% CI, 1.26-1.39). CONCLUSIONS: In this large real-world study, low adherence DOAC was associated with higher risk of TE events as compared to high and low adherence warfarin.

Optimal conditions for high-power, short-duration radiofrequency ablation using a novel, flexible-tipped, force-sensing catheter.

Background: High-power, short-duration (HPSD) radiofrequency ablation (RFA) reduces procedure time; however, safety and efficacy thresholds vary with catheter design. Objective: The study sought to determine optimal HPSD ablation conditions with a novel flexible-tipped, contact force-sensing RFA catheter. Methods: RFA lesions were created in thigh muscle (16 swine) over a range of conditions (51-82 W, 2-40 g, 8-40 mL/min irrigation). An intracardiac study was performed (12 swine) to characterize steam pop thresholds. Lesions were created in a second intracardiac study (14 swine, n = 290 pulmonary vein isolation [PVI] lesions) with combinations of radiofrequency power, duration, and contact force. PVI was tested, animals were sacrificed, and lesions were measured. Results: The likelihood of coagulation formation in the thigh model was <20% when power was ≤79 W, when contact force was ≤40 g, when duration was ≤11 seconds, and when irrigation rates were 8 to 40 mL/min. The impact of contact force on lesion safety and efficacy was more pronounced using HPSD (60 W/8 seconds) compared with conventional ablation (30 W/45 seconds) (P = .038). During PVI, focal atrial lesions ranged in width from 4.2 to 12.5 mm and were transmural 80.8% of the time. PVI was achieved in 13 of 14 veins. Logistic regression identified that the optimal parameters for radiofrequency application were 60 to 70 W with a duration <8 seconds and <15 g contact force. Conclusions: Optimal HPSD lesions with this this flexible-tipped, force-sensing RFA catheter were created at 60 to 70 W for <8 seconds with <15 g contact force. Chronic studies are ongoing to assess radiofrequency parameter refinements and long-term lesion durability using these conditions.

Substrate Imaging Before Catheter Ablation of Ventricular Tachycardia: Risk Prediction for Acute Hemodynamic Decompensation.

BACKGROUND: The PAINESD (Pulmonary disease, Age, Ischemic cardiomyopathy, NYHA functional class, Ejection fraction, Storm, Diabetes mellitus) risk score has been validated as a predictor of periprocedural acute hemodynamic decompensation (AHD) in patients undergoing ventricular tachycardia (VT) ablation. Whether the addition of total scar volume (TSV) determined by preprocedure computed tomography imaging provides additional risk stratification has not been previously investigated. OBJECTIVES: The purpose of this study was to evaluate the impact of TSV on the risk of AHD and its adjunctive benefit to the PAINESD score newly modified as Pulmonary disease, Age, Ischemic cardiomyopathy, NYHA class, Ejection fraction, Storm, Scar volume, Diabetes mellitus (PAINES2D) based on the addition of scar volumes. METHODS: This was a retrospective analysis of all index VT ablations at a quaternary care center from 2017 to 2022. Associations between TSV and AHD were evaluated among patients with structural heart disease. RESULTS: Among 61 patients with TSV data, 13 (21%) had periprocedural AHD. TSV and PAINESD were independently associated with AHD risk. Both TSV and PAINESD were associated with AHD (P = 0.016 vs P = 0.053, respectively). The highest TSV tertile (≥37.30 mL) showed significant association with AHD (P = 0.018; OR: 4.80) compared to the other tertiles. The PAINESD and PAINES2D scores had significant impact on AHD (P = 0.046 and P = 0.010, respectively). The PAINES2D score had a greater impact on AHD compared to PAINESD (area under the curve: 0.73; P = 0.011; 95% CI: 0.56-0.91 and area under the curve: 0.67; P = 0.058; 95% CI: 0.49-0.85, respectively). CONCLUSIONS: Addition of TSV to a modified PAINESD score, PAINES2D, enhances risk prediction of AHD. Further prospective study is needed to assess benefit in various cardiomyopathy populations undergoing VT ablation.

Coronary Venous Mapping and Ablation for Ventricular Tachycardia.

Coronary venous mapping and ablation can be an effective strategy in targeting ventricular arrhythmias that arise from intramural or epicardial sites of origin. We discuss the case of a patient with ischemic cardiomyopathy referred to our center for index ventricular tachycardia ablation after receiving multiple shocks from his implantable cardioverter-defibrillator who underwent coronary venous mapping and ablation as an adjunct to endocardial ventricular tachycardia ablation.

Epicardial mapping and ablation of ventricular tachycardia from the coronary venous system in post-coronary bypass patients.

BACKGROUND: Ventricular tachycardia (VT) ablation of mid- or epicardial substrate is difficult and requires a creative approach in patients with a history of coronary bypass that precludes percutaneous epicardial catheter manipulation. The coronary venous system (CVS) provides limited access to the epicardial surface of the heart. The objective of this study is to assess the feasibility, safety, and efficacy of epicardial mapping and ablation of VT substrates from the CVS in patients with history of coronary bypass. METHODS: Patients undergoing VT ablation at our institution were retrospectively reviewed. Those who had basal to mid ventricular substrate based on computed tomography imaging and history of coronary bypass were included. Endocardial and CVS mapping and ablation was performed in standard fashion using 3D electroanatomic mapping. The primary endpoint was defined as VT circuit elimination, termination, non-inducibility, or perturbation of the circuit. RESULTS: Of 192 consecutive VT ablations from 2017 to 2020, 35 (18%) had a history of coronary bypass and basal to the mid-ventricular substrate by imaging. There were no significant characteristic differences between the endocardial only (n = 19) vs endocardial + CVS (n = 16) groups. In 14 (88%) of patients undergoing CVS mapping, the VT circuit was identified to be within access from the epicardial surface. Ablation was attempted in 8 (57%) of these patients, and the primary endpoint was reached in 88% of those undergoing CVS ablation. There were no complications related to CVS ablation. CONCLUSION: Mapping and ablation of mid- or epicardial VT circuits from the CVS branches are feasible and safe and may be helpful in the treatment of VT in patients who are otherwise not candidates for percutaneous epicardial ablation.

A systematic review and meta-analysis comparing radiofrequency catheter ablation with medical therapy for ventricular tachycardia in patients with ischemic and non-ischemic cardiomyopathies.

BACKGROUND: In patients with cardiomyopathy, radiofrequency catheter ablation (CA) for ventricular tachycardia (VT) is an adjunctive and alternative treatment option to long-term anti-arrhythmic drug therapy. We sought to compare CA with medical therapy for the management of VT in patients with ischemic and non-ischemic cardiomyopathies. METHODS: MEDLINE, Cochrane, and ClinicalTrials.gov databases were evaluated for relevant studies. RESULTS: Eleven studies with 2126 adult patients were included (711 in CA, 1415 in medical therapy). In the randomized controlled trial (RCT) analysis, CA reduced risk of recurrent VT (risk ratio (RR) 0.79 [95% CI 0.67 to 0.93], p = 0.005), ICD shocks (RR 0.64 [95% CI 0.45 to 0.89] p = 0.008), and cardiac hospitalizations (RR 0.76 [95% CI 0.63 to 0.92] p = 0.005). There was no difference in all-cause mortality (RR 0.94, p = 0.71). In combined RCT and observational study analysis, there was a trend for reduction in all-cause mortality (RR 0.75 [95% CI 0.55 to 1.02] p = 0.07). In subgroup analysis of studies with mean left ventricular ejection fraction (LVEF) < 35%, CA demonstrated reduction in mortality (RR 0.71, p = 0.004), ICD shocks (RR 0.63, p = 0.03), VT recurrence (RR 0.76, p = 0.004), and cardiac hospitalizations (RR 0.75, p = 0.02). The subgroup of early CA prior to ICD shocks demonstrated reduction in ICD shocks (RR 0.57, p < 0.001) and VT recurrence (RR 0.74, p = 0.01). CONCLUSIONS: CA for VT demonstrated a lower risk of VT recurrence, ICD shocks, and hospitalization in comparison to medical therapy. The subgroups of early CA and LVEF < 35% demonstrated better outcomes.

Non-invasive localization of premature ventricular focus: A prospective multicenter study.

BACKGROUND: Accurate localization of premature ventricular contractions (PVC) focus is a prerequisite to successful catheter ablation. OBJECTIVE: The objective was to evaluate the software View Into Ventricular Onset (VIVO) accuracy at locating the anatomical origins for premature ventricular contractions. The VIVO device noninvasively creates a model of the patient's heart and torso, with exact locations of 12­lead ECG electrodes, and applies a mathematical algorithm from surface signals to determine the origin of the arrhythmia. We sought to compare the agreement between VIVO-predicted locations to invasive electroanatomical mapping results. METHODS: 51 consecutive patients who presented for PVC ablations at the study centers were recruited. VIVO images were collected at baseline preprocedure and all patients underwent invasive electroanatomical activation mapping of the clinical arrhythmia. Pacing was performed in pre-specified locations in the right and/or left ventricle. The successful sites of ablation and the pacing locations were compared to VIVO predicted locations. The results were adjudicated by physician experts in a blinded fashion. RESULTS: Seven patients were excluded from analyses. VIVO accurately identified the origin of the clinical premature ventricular contractions in 44/44 patients (100.00%). The accuracy in identifying the paced location for all patients (right and left sides of the heart) was 99.5% using the VIVO system. No adverse events were reported. CONCLUSIONS: VIVO is a novel noninvasive system that could be used to help guide ablation procedures with a high degree of accuracy. The VIVO algorithm is easy to use and may be useful in the workflow for ventricular arrhythmia ablation.

Comparison of ablation index versus time-guided radiofrequency energy dosing using normal and half-normal saline irrigation in a porcine left ventricular model.

BACKGROUND: Ablation Index (AI) is a multiparametric quality marker to assess the durability of radiofrequency (RF) lesions. The comparative effectiveness and safety of AI versus time-based energy dosing for ablation of ventricular arrhythmias are unknown. OBJECTIVE: We compared AI and time-based RF dosing strategies in the left ventricles (LVs) of freshly harvested porcine hearts. METHODS: Ablation was performed in vitro with an open-irrigated ablation catheter (Thermocool ST/SF), 40 W, contact force 10-15 g. Tissue samples were stained in triphenyltetrazolium chloride for the measurement of lesion dimensions. RESULTS: A total of 560 lesions were performed (AI-group: [n = 360]; time-group: [n = 200]). Using normal saline (NS) (n = 280), growth in lesion depth slowed after 30 s and AI > 550 in comparison to width, volume, and magnitude of impedance drops which continued to increase with longer RF duration. Risk of steam pop (SP) was higher for RF > 30 s (RF < 30 s:1 SP [2.5%] vs. RF > 30 s: 15 SP [25%]; p = .002) or AI targets >550 (AI: 350-550: 2 SP [2%] vs. AI 600-750: 15 SP [19%]; p = .001). Using half-normal saline (HNS) (n = 280), lesion dimension and impedance drops were larger and growth in lesion depth slowed earlier (AI: 500). Risk of SPs was higher above AI 550 (AI: 350-550: 7 [7%] SPs vs. AI 600-750: 28 [35%] SPs; p < .00001). While codependent variables, correlation between AI and time was modest-to-strong but decreased with longer RF duration. CONCLUSION: In this ex vivo study, AI was a better predictor of lesion dimensions than ablation time and magnitude of impedance drop in the LV using NS and HNS irrigation. AI targets above 550 led to a higher risk of SPs. Future trials are required to verify these findings.

Comparison of radiofrequency ablation from the coronary cusps and endocardial left ventricular outflow tract for left ventricular summit ventricular arrhythmias in a porcine and infrared thermal model.

INTRODUCTION: The coronary cusps (CCs) are utilized as an alternative vantage point for radiofrequency catheter ablation (RFCA) of left ventricular summit ventricular arrhythmias but are sometimes a challenge despite favorable activation timing and pace mapping. METHODS: Ex vivo experiments were performed in 12 intact porcine hearts submerged in a 37°C saline bath. Radiofrequency (RF) applications were delivered with an irrigated contact force sensing catheter oriented 45° to the endocardial left ventricular outflow tract (LVOT) surface and nadir of the CCs using different dosing parameters. Sections were stained in 2% triphenyltetrazolium chloride and lesion dimensions were measured. Thermal infrared imaging analysis was used to compare time-to-lethal tissue temperature and depth/area of lethal isotherms. RESULTS: A total of 60 RF applications were performed under different dosing parameters for (1) 30, 40, and 50 Watts (W) × 30 s and (2) 40 W × 30, 45, and 60 s. Lesion depth was greater with RFCA from LVOT than from the CCs (maximum depth 6.11 vs. 2.68 mm). Longer RF duration led to larger lesion volume in the CC group (40 W × 30 s: 8.1 ± 0.4 vs. 40 W × 60 s: 10.1 ± 0.96 mm; p = .002). One steam pop occurred in both the LVOT (50 W × 30 s) and CC groups (40 W × 60 s). Time-to-reach lethal temperature of 58°C was longer in the CC group than in the LVOT group (4.7 vs. 11.3 s; p = .02) CONCLUSIONS: RFCA from the CC led comparatively to shallower lesion depth than from the LVOT. Longer RF duration led to an increase in lesion volume during ablation from CCs.

Noncontact whole-chamber charge density mapping of the left ventricle: Preclinical evaluation in a sheep model.

BACKGROUND: Conventional contact-based electroanatomic mapping is poorly suited for rapid or dynamic ventricular arrhythmias. Whole-chamber charge density (CD) mapping could efficiently characterize complex ventricular tachyarrhythmias and yield insights into their underlying mechanisms. OBJECTIVE: The purpose of this study was to evaluate the feasibility and accuracy of noncontact whole-chamber left ventricular (LV) CD mapping and to characterize CD activation patterns during sinus rhythm, ventricular pacing, and ventricular fibrillation (VF). METHODS: Ischemic scar as defined by CD amplitude thresholds was compared to late gadolinium enhancement criteria on magnetic resonance imaging using an iterative closest point algorithm. Electrograms recorded at sites of tissue contact were compared to the nearest noncontact CD-derived electrograms to calculate signal morphology cross-correlations and time differences. Regions of consistently slow conduction were examined relative to areas of scar and to localized irregular activation (LIA) during VF. RESULTS: Areas under receiver operating characteristic curves (AUCs) of CD-defined dense and total LV scar were 0.92 ± 0.03 and 0.87 ± 0.06, with accuracies of 0.86 ± 0.03 and 0.80 ± 0.05, respectively. Morphology cross-correlation between 8677 contact and corresponding noncontact electrograms was 0.93 ± 0.10, with a mean time difference of 2.5 ± 5.6 ms. Areas of consistently slow conduction tended to occur at scar borders and exhibited spatial agreement with LIA during VF (AUC 0.90 ± 0.02). CONCLUSION: Noncontact LV CD mapping can accurately delineate ischemic scar. CD-derived ventricular electrograms correlate strongly with conventional contact-based electrograms. Regions with consistently slow conduction are often at scar borders and tend to harbor LIA during VF.