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.

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.

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.

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.

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.

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.

Non-contact 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

This study sought to evaluate the feasibility and accuracy of non-contact 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 non-contact 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 8,677 contact and corresponding non-contact electrograms was 0.93±0.10, with a mean time difference of 2.5±5.6 msec. 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

Non-contact 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.

Cardioneuroablation for cardioinhibitory vasovagal syncope

BACKGROUND

Cardioneuroablation (CNA) is an emerging technique being used to treat patients with cardioinhibitory vasovagal syncope (VVS). We describe a case of CNA in targeting atrial ganglionated plexi (GP) based upon anatomical landmarks and fractionated electrogram (EGM) localization in a patient with cardioinhibitory syncope.

CASE PRESENTATION

A 20-year-old healthy female presented with malignant VVS and symptomatic sinus pauses, with the longest detected at 10 s. She underwent acutely successful CNA with demonstration of vagal response (VR) noted after ablation of left sided GP, and tachycardia noted with right sided GP ablation. All GP sites were defined by anatomical landmarks and EGM analysis. By using the fractionation mapping software of Ensite Precision mapping system with high density mapping, fragmented EGMs were successfully detected in each GP site. One month after vagal denervation, there were no recurrent syncopal episodes or sinus pauses. Longer term follow-up with implantable loop recorder is planned.

CONCLUSION

We performed CNA in a patient with VVS by utilizing a novel approach of combined use of high density mapping and fractionation mapping software. With this approach, we were able to detect fractionation in all GP sites and demonstrate acute VR. This workflow may allow for a new, standardized technique suitable for widespread use.

Fractionation Mapping of the Ganglionated Plexi for Cardioneuroablation

Cardioneuroablation (CNA) is an emerging technique used to treat patients with vasovagal syncope (VVS). We herein describe a case of CNA targeting the atrial ganglionated plexi (GPs) based upon anatomical landmarks and fractionated electrogram (EGM) localization in a 20-year-old healthy female who presented to our center with malignant VVS and symptomatic sinus pauses, the longest of which measured 10 seconds. She underwent acutely successful CNA with a demonstration of vagal response noted following ablation of the left-sided GPs, and tachycardia was noted with right-sided GP ablation. All GP sites were defined by anatomical landmarks and EGM analysis. By using the fractionation mapping software of the EnSite Precision™ cardiac mapping system (Abbott, Chicago, IL, USA) with high-density mapping, fragmented EGMs were successfully detected in each GP site. One month after vagal denervation, no recurrent syncopal episodes or sinus pauses had been recorded. Longer-term follow-up with an implantable loop recorder is planned. Broadly, we performed CNA in a patient with VVS by combining high-density mapping and fractionation mapping software in a novel approach, which allowed us to detect fractionation in all GP sites and demonstrate an acute vagal response. This workflow may facilitate the introduction of a standardized technique suitable for widespread use.

Impact of age on catheter ablation of premature ventricular contractions

INTRODUCTION

Catheter ablation (CA) of frequent premature ventricular contractions (PVC) is increasingly performed in older patients as the population ages. The aim of this study was to assess the impact of age on procedural characteristics, safety and efficacy on PVC ablations.

METHODS

Consecutive patients with symptomatic PVCs undergoing CA between 2015 and 2020 were evaluated. Acute ablation success was defined as the elimination of PVCs at the end of the procedure. Sustained success was defined as an elimination of symptoms, and ≥80% reduction of PVC burden determined by Holter-electrocardiogram during long-term follow. Patients were sub-grouped based on age (<65 vs. ≥65 years).

RESULTS

A total of 114 patients were enrolled (median age 64 years, 71% males) and followed up for a median duration of 228 days. Baseline and procedural data were similar in both age groups. A left-sided origin of PVCs was more frequently observed in the elderly patient group compared to younger patients (83% vs. 67%; p = .04). The median procedure time was significantly shorter in elderly patients (160 vs. 193 min; p = .02). The rates of both acute (86% vs. 92%; p = .32) and sustained success (70% vs. 71%; p = .90) were similar between groups. Complications rates (3.7%) did not differ between the two groups.

CONCLUSION

In a large series of patients with a variety of underlying arrhythmia substrates, similar rates of acute procedural success, complications, and ventricular arrhythmia-free-survival were observed after CA of PVCs. Older age alone should not be a reason to withhold CA of PVCs.

Clinical Applications of Laser Technology: Laser Balloon Ablation in the Management of Atrial Fibrillation

Catheter-based ablation techniques have a well-established role in atrial fibrillation (AF) management. The prevalence and impact of AF is increasing globally, thus mandating an emphasis on improving ablation techniques through innovation. One key area of ongoing evolution in this field is the use of laser energy to perform pulmonary vein isolation during AF catheter ablation. While laser use is not as widespread as other ablation techniques, such as radiofrequency ablation and cryoballoon ablation, advancements in product design and procedural protocols have demonstrated laser balloon ablation to be equally safe and effective compared to these other modalities. Additionally, strategies to improve procedural efficiency and decrease radiation exposure through low fluoroscopy protocols make this technology an increasingly promising and exciting option.

Intracardiac echocardiography use and outcomes after catheter ablation of ventricular tachycardia

Aim: To compare outcomes among patients with implantable cardioverter defibrillator/cardiac resynchronization therapy-defibrillator undergoing outpatient ventricular tachycardia (VT) catheter ablation using intracardiac echocardiography (ICE) versus no ICE. Patients & methods: Patients were classified into ICE (n = 1143)/non-ICE (n = 1677) groups based on ICE procedure codes. Patients in each group were propensity matched on study covariates. Survival analyses were used to assess outcomes. To examine residual confounding, falsification outcomes were evaluated. Results: ICE patients had a 24% lower risk of all-cause readmissions, 24% lower risk of cardiovascular-related and 20% lower risk of VT-related readmissions compared with non-ICE patients. Falsification analyses for ICE use association were nonsignificant. Conclusion: Patients with implantable cardioverter defibrillator/cardiac resynchronization therapy-defibrillator undergoing VT ablation with ICE use had significantly lower likelihood of VT-related readmission.

Real-world outcomes of ventricular tachycardia catheter ablation with versus without intracardiac echocardiography

INTRODUCTION

By providing real-time monitoring of catheter-tissue interface and for complications, intracardiac echocardiography (ICE) during catheter ablation for ventricular tachycardia (VT) may improve outcomes. To test this hypothesis, we compared 12-month readmission rates (all-cause, cardiovascular [CV]-related, and VT-related), repeat ablation, and complications among patients with VT with structural heart disease undergoing ablation with versus without ICE.

METHODS AND RESULTS

Using the 2008-2017 IBM MarketScan Commercial and Medicare Supplemental databases, patients with a history of implantable cardioverter defibrillator/cardiac resynchronization therapy (ICD/CRT-D) who underwent VT ablation with and without ICE use were identified. Propensity matching was performed and regression analysis was used to compare outcomes. After matching, 1324 patients were identified (ICE: 662; non-ICE: 662). The rate of 12-month VT-related readmission (18.13% vs 22.51%; P < .05) and repeat VT ablation (14.35% vs 19.34%; P = .02) postindex discharge were lower among patients in the ICE group compared with the non-ICE group, with a 24% lower risk of 12-month VT-related readmission (odds ratio [OR], 0.76; 95% confidence interval [CI], 0.58-0.99) and a 30% lower risk of repeat ablation (OR, 0.70; 95% CI, 0.52-0.93) vs non-ICE group. The 12-month all-cause (44.56% vs 43.20%; P = .62) and CV-related readmissions (35.20% vs 32.93%; P = 0.38) and complication rates were not significantly different between the two groups.

CONCLUSIONS

VT ablation using ICE was associated with a lower likelihood of 12-month VT-related readmission and repeat ablation compared with non-ICE patients.

Altered desmosomal proteins in granulomatous myocarditis and potential pathogenic links to arrhythmogenic right ventricular cardiomyopathy

BACKGROUND

Immunoreactive signal for the desmosomal protein plakoglobin (γ-catenin) is reduced at cardiac intercalated disks in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC), a highly arrhythmogenic condition caused by mutations in genes encoding desmosomal proteins. Previously, we observed a false-positive case in which plakoglobin signal was reduced in a patient initially believed to have ARVC but who actually had cardiac sarcoidosis. Sarcoidosis can masquerade clinically as ARVC but has not been previously associated with altered desmosomal proteins.

METHODS AND RESULTS

We observed marked reduction in immunoreactive signal for plakoglobin at cardiac myocyte junctions in patients with sarcoidosis and giant cell myocarditis, both highly arrhythmogenic forms of myocarditis associated with granulomatous inflammation. In contrast, plakoglobin signal was not depressed in lymphocytic (nongranulomatous) myocarditis. To determine whether cytokines might promote dislocation of plakoglobin from desmosomes, we incubated cultures of neonatal rat ventricular myocytes with selected inflammatory mediators. Brief exposure to low concentrations of interleukin (IL)-17, tumor necrosis factor-α (TNF-α), and IL-6 (cytokines implicated in granulomatous myocarditis) caused translocation of plakoglobin from cell-cell junctions to intracellular sites, whereas other potent cytokines implicated in nongranulomatous myocarditis had no effect, even at much higher concentrations. We also observed myocardial expression of IL-17 and TNF-α and elevated levels of serum inflammatory mediators, including IL-6R, IL-8, monocyte chemoattractant protein 1, and macrophage inflammatory protein 1β, in patients with ARVC (all P<0.0001 compared with controls).

CONCLUSIONS

The results suggest novel disease mechanisms involving desmosomal proteins in granulomatous myocarditis and implicate cytokines, perhaps derived in part from the myocardium, in disruption of desmosomal proteins and arrhythmogenesis in ARVC.

Drug-sensitized zebrafish screen identifies multiple genes, including GINS3, as regulators of myocardial repolarization

BACKGROUND

Cardiac repolarization, the process by which cardiomyocytes return to their resting potential after each beat, is a highly regulated process that is critical for heart rhythm stability. Perturbations of cardiac repolarization increase the risk for life-threatening arrhythmias and sudden cardiac death. Although genetic studies of familial long-QT syndromes have uncovered several key genes in cardiac repolarization, the major heritable contribution to this trait remains unexplained. Identification of additional genes may lead to a better understanding of the underlying biology, aid in identification of patients at risk for sudden death, and potentially enable new treatments for susceptible individuals.

METHODS AND RESULTS

We extended and refined a zebrafish model of cardiac repolarization by using fluorescent reporters of transmembrane potential. We then conducted a drug-sensitized genetic screen in zebrafish, identifying 15 genes, including GINS3, that affect cardiac repolarization. Testing these genes for human relevance in 2 concurrently completed genome-wide association studies revealed that the human GINS3 ortholog is located in the 16q21 locus, which is strongly associated with QT interval.

CONCLUSIONS

This sensitized zebrafish screen identified 15 novel myocardial repolarization genes. Among these genes is GINS3, the human ortholog of which is a major locus in 2 concurrent human genome-wide association studies of QT interval. These results reveal a novel network of genes that regulate cardiac repolarization.

Blocking the renin-angiotensin-aldosterone system to prevent diabetes mellitus

Type 2 diabetes mellitus (DM) is increasing around the world, and the public health impact of DM, driven largely by cardiovascular disease complications, underpins the importance of continued efforts toward primary prevention of DM. Only a few interventions have been shown to prevent DM, with none of them yet proven to improve cardiovascular risk commensurately. Accumulating evidence suggest that drugs that block the renin-angiotensin-aldosterone system (RAAS), many of which have proven cardiovascular disease (CVD) benefit, also have favourable effects on parameters of glucose metabolism and incident diabetes. Here we review the evidence accumulated to date from animal studies, clinical mechanistic studies and clinical trials regarding the effect of RAAS inhibition and incident DM.

A hot spot for the interaction of gating modifier toxins with voltage-dependent ion channels

The gating modifier toxins are a large family of protein toxins that modify either activation or inactivation of voltage-gated ion channels. omega-Aga-IVA is a gating modifier toxin from spider venom that inhibits voltage-gated Ca(2+) channels by shifting activation to more depolarized voltages. We identified two Glu residues near the COOH-terminal edge of S3 in the alpha(1A) Ca(2+) channel (one in repeat I and the other in repeat IV) that align with Glu residues previously implicated in forming the binding sites for gating modifier toxins on K(+) and Na(+) channels. We found that mutation of the Glu residue in repeat I of the Ca(2+) channel had no significant effect on inhibition by omega-Aga-IVA, whereas the equivalent mutation of the Glu in repeat IV disrupted inhibition by the toxin. These results suggest that the COOH-terminal end of S3 within repeat IV contributes to forming a receptor for omega-Aga-IVA. The strong predictive value of previous mapping studies for K(+) and Na(+) channel toxins argues for a conserved binding motif for gating modifier toxins within the voltage-sensing domains of voltage-gated ion channels.