Interactive teaching of medical 3D cardiac anatomy: atrial anatomy enhanced by ECG and 3D visualization

The most commonly applied way of teaching students to convey the foundations of human anatomy and physiology involves textbooks and lectures. This way of transmitting knowledge causes difficulties for students, especially in the context of three-dimensional imaging of organ structures, and as a consequence translates into difficulties with imagining them. Even despite the rapid uptake of knowledge dissemination provided by online materials, including courses and webinars, there is a clear need for learning programs featuring first-hand immersive experiences tailored to suit individual study paces. In this paper, we present an approach to enhance a classical study program by combining multi-modality data and representing them in a Mixed Reality (MR)-based environment. The advantages of the proposed approach have been proven by the conducted investigation of the relationship between atrial anatomy, its electrophysiological characteristics, and resulting P wave morphology on the electrocardiogram (ECG). Another part of the paper focuses on the role of the sinoatrial node in ECG formation, while the MR-based visualization of combined micro-computed tomography (micro-CT) data with non-invasive CineECG imaging demonstrates the educational application of these advanced technologies for teaching cardiac anatomy and ECG correlations.

Palpitations in athletes: diagnosis, workup and treatment

Palpitations are a common reason for athletes to seek medical care. Although often benign, palpitations may serve as a harbinger for underling cardiac pathology. Given the unique challenges in this population, this review will serve to discuss the basic underlying pathophysiology, which may predispose athletes to palpitations. In addition, we will review the aetiologies, diagnostic evaluation, management and counselling strategies for some of the most common diagnoses seen in athletes.

Catheter ablation of ventricular tachycardia in patients with arrhythmogenic right ventricular cardiomyopathy and biventricular involvement

AIMS

Catheter ablation of ventricular tachycardia (VT) improves VT-free survival in 'classic' arrhythmogenic right ventricular cardiomyopathy (ARVC). This study aims to investigate electrophysiological features and ablation outcomes in patients with ARVC and biventricular (BiV) involvement.

METHODS AND RESULTS

We assembled a retrospective cohort of definite ARVC cases with sustained VTs. Patients were divided into the BiV (BiV involvement) group and the right ventricular (RV) (isolated RV involvement) group based on the left ventricular systolic function detected by cardiac magnetic resonance. All patients underwent electrophysiological mapping and VT ablation. Acute complete success was non-inducibility of any sustained VT, and the primary endpoint was VT recurrence. Ninety-eight patients (36 ± 14 years; 87% male) were enrolled, including 50 in the BiV group and 48 in the RV group. Biventricular involvement was associated with faster clinical VTs, a higher VT inducibility, and more extensive arrhythmogenic substrates (all P < 0.05). Left-sided VTs were observed in 20% of the BiV group cases and correlated with significantly reduced left ventricular systolic function. Catheter ablation achieved similar acute efficacy between these two groups, whereas the presence of left-sided VTs increased acute ablation failure (40 vs. 5%, P = 0.012). Over 51 ± 34 months [median, 48 (22-83) months] of follow-up, cumulative VT-free survival was 52% in the BiV group and 58% in the RV group (P = 0.353). A multivariate analysis showed that younger age, lower RV ejection fraction (RVEF), and non-acute complete ablation success were associated with VT recurrence in the BiV group.

CONCLUSION

Biventricular involvement implied a worse arrhythmic phenotype and increased the risk of left-sided VTs, while catheter ablation maintained its efficacy for VT control in this population. Younger age, lower RVEF, and non-acute complete success predicted VT recurrence after ablation.

Anesthetic Management for Ventricular Tachycardia Ablation: A National Anesthesia Clinical Outcomes Registry Analysis

OBJECTIVES

The authors analyzed anesthetic management trends during ventricular tachycardia (VT) ablation, hypothesizing that (1) monitored anesthesia care (MAC) is more commonly used than general anesthesia (GA); (2) MAC uses significantly increased after release of the 2019 Expert Consensus Statement on Catheter Ablation of Ventricular Arrhythmias; and (3) anesthetic approach varies based on patient and hospital characteristics.

DESIGN

Retrospective study.

SETTING

National Anesthesia Clinical Outcomes Registry data.

PARTICIPANTS

Patients 18 years or older who underwent elective VT ablation between 2013 and 2021.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Covariates were selected a priori within multivariate models, and interrupted time-series analysis was performed. Of the 15,505 patients who underwent VT ablation between 2013 and 2021, 9,790 (63.1%) received GA. After the 2019 Expert Consensus Statement on Catheter Ablation of Ventricular Arrhythmias supported avoidance of GA in idiopathic VT, no statistically significant increase in MAC was evident (immediate change in intercept post-consensus statement release adjusted odds ratio 1.41, p = 0.1629; change in slope post-consensus statement release adjusted odds ratio 1.06 per quarter, p = 0.1591). Multivariate analysis demonstrated that sex, American Society of Anesthesiologists physical status, age, and geographic location were statistically significantly associated with the anesthetic approach.

CONCLUSIONS

GA has remained the primary anesthetic type for VT ablation despite the 2019 Expert Consensus Statement on Catheter Ablation of Ventricular Arrhythmias suggested its avoidance in idiopathic VT. Achieving widespread clinical practice change is an ongoing challenge in medicine, emphasizing the importance of developing effective implementation strategies to facilitate awareness of guideline release and subsequent adherence to and adoption of recommendations.

Real-time cardiovascular magnetic resonance-guided radiofrequency ablation: A comprehensive review

Cardiac magnetic resonance (CMR) imaging could enable major advantages when guiding in real-time cardiac electrophysiology procedures offering high-resolution anatomy, arrhythmia substrate, and ablation lesion visualization in the absence of ionizing radiation. Over the last decade, technologies and platforms for performing electrophysiology procedures in a CMR environment have been developed. However, performing procedures outside the conventional fluoroscopic laboratory posed technical, practical and safety concerns. The development of magnetic resonance imaging compatible ablation systems, the recording of high-quality electrograms despite significant electromagnetic interference and reliable methods for catheter visualization and lesion assessment are the main limiting factors. The first human reports, in order to establish a procedural workflow, have rationally focused on the relatively simple typical atrial flutter ablation and have shown that CMR-guided cavotricuspid isthmus ablation represents a valid alternative to conventional ablation. Potential expansion to other more complex arrhythmias, especially ventricular tachycardia and atrial fibrillation, would be of essential impact, taking into consideration the widespread use of substrate-based strategies. Importantly, all limitations need to be solved before application of CMR-guided ablation in a broad clinical setting.

Antiplatelet and Anti-Coagulation Therapy for Left-Sided Catheter Ablations: What Is beyond Atrial Fibrillation?

Aim: International guidelines on the use of anti-thrombotic therapies in left-sided ablations other than atrial fibrillation (AF) are lacking. The data regarding antiplatelet or anticoagulation strategies after catheter ablation (CA) procedures mainly derive from AF, whereas for the other arrhythmic substrates, the anti-thrombotic approach remains unclear. This survey aims to explore the current practices regarding antithrombotic management before, during, and after left-sided endocardial ablation, not including atrial fibrillation (AF), in patients without other indications for anti-thrombotic therapy. Material and Methods: Electrophysiologists were asked to answer a questionnaire containing questions on antiplatelet (APT) and anticoagulation therapy for the following left-sided procedures: accessory pathway (AP), atrial (AT), and ventricular tachycardia (VT) with and without structural heart disease (SHD). Results: We obtained 41 answers from 41 centers in 15 countries. For AP, before ablation, only four respondents (9.7%) used antiplatelets and two (4.9%) used anticoagulants. At discharge, APT therapy was prescribed by 22 respondents (53.7%), and oral anticoagulant therapy (OAC) only by one (2.4%). In patients with atrial tachycardia (AT), before ablation, APT prophylaxis was prescribed by only four respondents (9.7%) and OAC by eleven (26.8%). At discharge, APT was recommended by 12 respondents (29.3%) and OAC by 24 (58.5%). For VT without SHD, before CA, only six respondents (14.6%) suggested APT and three (7.3%) suggested OAC prophylaxis. At discharge, APT was recommended by fifteen respondents (36.6%) and OAC by five (12.2%). Regarding VT in SHD, before the procedure, eight respondents (19.5%) prescribed APT and five (12.2%) prescribed OAC prophylaxis. At discharge, the administration of anti-thrombotic therapy depended on the LV ejection fraction for eleven respondents (26.8%), on the procedure time for ten (24.4%), and on the radiofrequency time for four (9.8%), with a cut-off value from 1 to 30 min. Conclusions: Our survey indicates that the management of anti-thrombotic therapy surrounding left-sided endocardial ablation of patients without other indications for anti-thrombotic therapy is highly variable. Further studies are necessary to evaluate the safest approach to these procedures.

Impact of Cardiac Magnetic Resonance to Arrhythmic Risk Stratification in Nonischemic Cardiomyopathy

Left ventricular ejection fraction-based arrhythmic risk stratification in nonischemic cardiomyopathy (NICM) is insufficient and has led to the failure of primary prevention implantable cardioverter defibrillator trials, mainly due to the inability of selecting patients at high risk for sudden cardiac death (SCD). Cardiac magnetic resonance offers unique opportunities for tissue characterization and has gained a central role in arrhythmic risk stratification in NICM. The presence of myocardial scar, denoted by late gadolinium enhancement, is a significant, independent, and strong predictor of ventricular arrhythmias and SCD with high negative predictive value. T1 maps and extracellular volume fraction, which are able to quantify diffuse fibrosis, hold promise as complementary tools but need confirmatory results from large studies.

Endomyocardial substrate of ventricular arrhythmias in patients with autoimmune rheumatic diseases

INTRODUCTION

Delayed enhancement-magnetic resonance imaging (DE-MRI) has demonstrated that nonischemic cardiomyopathy is mainly characterized by intramural or epicardial fibrosis whereas global endomyocardial fibrosis suggests cardiac involvement in autoimmune rheumatic diseases or amyloidosis. Conduction disorders and sudden cardiac death are important manifestations of autoimmune rheumatic diseases with cardiac involvement but the substrates of ventricular arrhythmias in autoimmune rheumatic diseases have not been fully elucidated.

METHODS AND RESULTS

20 patients with autoimmune rheumatic diseases presenting with ventricular tachycardia (VT) (n = 11) or frequent ventricular extrasystoles (n = 9) underwent DE-MRI and/or endocardial electroanatomical mapping of the left ventricle (LV). Ten patients with autoimmune rheumatic diseases underwent VT ablation. Global endomyocardial fibrosis without myocardial thickening and unrelated to coronary territories was detected by DE-MRI or electroanatomical voltage mapping in 9 of 20 patients with autoimmune rheumatic diseases. In the other patients with autoimmune rheumatic diseases, limited regions of predominantly epicardial (n = 4) and intramyocardial (n = 5) fibrosis or only minimal fibrosis (n = 2) were found using DE-MRI. Endocardial low-amplitude diastolic potentials and pre-systolic Purkinje or fascicular potentials, mostly within fibrotic areas, were identified as the targets of successful VT ablation in 7 of 10 patients with autoimmune rheumatic diseases.

CONCLUSION

Global endomyocardial fibrosis can be a tool to diagnose severe cardiac involvement in autoimmune rheumatic diseases and may serve as the substrate of ventricular arrhythmias in a substantial part of patients.

Quelling the Storm: A Review of the Management of Electrical Storm

Heightened sympathetic input to the myocardium potentiates cardiac electrical instability and may herald an electrical storm. An electrical storm is characterized by 3 or more episodes of ventricular tachycardia, ventricular fibrillation, or appropriate internal cardiac defibrillator shocks within 24 hours. Management of electrical storms is resource-intensive and inevitably requires careful coordination between multiple subspecialties. Anesthesiologists have an important role in acute, subacute, and long-term management. Identifying the phase of an electrical storm and understanding the characteristics of each morphology may help the anesthesiologist anticipate the management approach. In the acute phase, management of an electrical storm is aimed at providing advanced cardiac life support and identifying reversible causes. After initial stabilization, subacute management focuses on dampening the sympathetic surge with sedation, thoracic epidural, or stellate ganglion blockade. Definitive long-term management with surgical sympathectomy or catheter ablation also may be warranted. Our objective is to provide an overview of electrical storms and the anesthesiologist's role in management.

Utility of cardiac imaging in patients with ventricular tachycardia

Ventricular tachycardia (VT) is a life-threatening arrhythmia that may be idiopathic or result from structural heart disease. Cardiac imaging is critical in the diagnostic workup and risk stratification of patients with VT. Data gained from cardiac imaging provides information on likely mechanisms and sites of origin, as well as risk of intervention. Pre-procedural imaging can be used to plan access route(s) and identify patients where post-procedural intensive care may be required. Integration of cardiac imaging into electroanatomical mapping systems during catheter ablation procedures can facilitate the optimal approach, reduce radiation dose, and may improve clinical outcomes. Intraprocedural imaging helps guide catheter position, target substrate, and identify complications early. This review summarises the contemporary imaging modalities used in patients with VT, and their uses both pre-procedurally and intra-procedurally.

Pleomorphic Ventricular Tachycardia in Dilated Cardiomyopathy Predicts Ventricular Tachycardia Recurrence After Ablation Independent From Cardiac Function: Comparison With Patients With Ischemic Heart Disease

BACKGROUND

In dilated cardiomyopathy (DCM), outcome after catheter ablation of ventricular tachycardia (VT) is modest, compared with ischemic heart disease (IHD). Pleomorphic VT (PL-VT) has been associated with fibrotic remodeling and end-stage heart failure in IHD. The prognostic role of PL-VT in DCM is unknown.

METHODS

Consecutive IHD (2009-2016) or DCM (2008-2018) patients undergoing ablation for monomorphic VT were included. PL-VT was defined as ≥1 spontaneous change of the 12-lead VT-morphology during the same induced VT episode. Patients were followed for VT recurrence and mortality.

RESULTS

A total of 247 patients (86% men; 63±13 years; IHD n=152; DCM n=95) underwent ablation for monomorphic VT. PL-VT was observed in 22 and 29 patients with IHD and DCM, respectively (14% versus 31%, P=0.003). In IHD, PL-VT was associated with lower LVEF (28±9% versus 34±12%, P=0.02) and only observed in those with LVEF<40%. In contrast, in DCM, PL-VT was not related to LVEF and induced in 27% of patients with LVEF>40%. During a median follow-up of 30 months, 79 (32%) patients died (IHD 48; DCM 31; P=0.88) and 120 (49%) had VT recurrence (IHD 59; DCM 61; P<0.001). PL-VT was associated with mortality in IHD but not in DCM. In IHD, VT recurrence was independently associated with LVEF, number of induced VTs, and procedural noncomplete success. Of note, in DCM, PL-VT (HR, 2.62 [95% CI, 1.47-4.69]), pathogenic mutation (HR, 2.13 [95% CI, 1.16-3.91]), and anteroseptal VT substrate (HR, 1.75 [95% CI, 1.00-3.07]) independently predicted VT recurrence.

CONCLUSIONS

In IHD, PL-VT was associated with low LVEF and mortality. In DCM, PL-VT was not associated with mortality but a predictor of VT recurrence independent from LVEF. PL-VT in DCM may indicate a specific arrhythmic substrate difficult to control by current ablation techniques.

The Effectiveness of Catheter Ablation in the Management of Ventricular Tachycardia in Comparison With Antiarrhythmic Drugs in Patients With Structural Heart Disease: A Meta-Analysis

The aim of this meta-analysis is to compare the safety and efficacy of catheter ablation versus antiarrhythmic drugs (AADs) in the management of ventricular tachycardia (VT) in patients with structural heart diseases. Two independent investigators searched electronic databases including PubMed, Cochrane, and Excerpta Medica database (EMBASE) using keyword combinations (Medical Subject Headings (MeSH) terms and free terms) such as "catheter ablation," "ventricular tachycardia," "escalation," and "antiarrhythmic drugs" from inception to November 30, 2022. The primary efficacy outcomes included recurrence of VT at follow-up, all-cause mortality, and cardiovascular mortality. The secondary efficacy outcomes assessed in the current meta-analysis included implantable cardioverter-defibrillator (ICD) shock and hospitalization due to cardiac reasons. Safety outcomes included treatment-related adverse events and serious adverse events. A total of three studies were included in this meta-analysis. There was no significant difference in the risk of recurrence of VT (RR: 0.94, 95% CI: 0.72-1.24, p-value: 0.67), all-cause mortality (RR: 0.99, 95% CI: 0.67, 1.46, p-value: 0.98), cardiovascular mortality (risk ratio (RR): 0.90, 95% confidence interval (CI): 0.56-1.45, p-value: 0.67), incidence of ICD shocks (RR: 0.99, 95% CI: 0.76-1.29, p-value: 0.93, I-square: 0%), and hospitalization due to cardiac reasons in follow-up (RR: 0.77, 95% CI: 0.55-1.07, p-value: 0.12) between the catheter ablation group and the antiarrhythmic drug group. However, the risk of treatment-related adverse events was lower in the ablation group compared to the antiarrhythmic medicine (AAM) group (RR: 0.44, 95% CI: 0.29-0.67, p-value: 0.0001). In this meta-analysis of three randomized controlled trials (RCTs) among patients with structural heart disease who had ventricular tachycardia, the incidence of the recurrence of VT, all-cause mortality, cardiovascular mortality, and ICD shock was not significantly different between patients who received catheter ablation and antiarrhythmic drugs. However, regarding safety, catheter ablation is a safe procedure with a low risk of treatment-related events compared to antiarrhythmic drugs.

Ablation of Refractory Ventricular Tachycardia Using Intramyocardial Needle Delivered Heated Saline-Enhanced Radiofrequency Energy: A First-in-Man Feasibility Trial

BACKGROUND

Ablation of ventricular tachycardia (VT) is limited by the inability to create penetrating lesions to reach intramyocardial origins. Intramural needle ablation using in-catheter, heated saline-enhanced radio frequency (SERF) energy uses convective heating to increase heat transfer and produce deeper, controllable lesions at intramural targets. This first-in-human trial was designed to evaluate the safety and efficacy of SERF needle ablation in patients with refractory VT.

METHODS

Thirty-two subjects from 6 centers underwent needle electrode ablation. Each had recurrent drug-refractory monomorphic VT after implantable cardioverter defibrillator implantation and prior standard ablation. During the SERF study procedure, one or more VTs were induced and mapped. The SERF needle catheter was used to create intramural lesions at targeted VT site(s). Acute procedural success was defined as noninducibility of the clinical VT after the procedure. Patients underwent follow-up at 30 days, and 3 and 6 months, with implantable cardioverter defibrillator interrogation at follow-up to determine VT recurrence.

RESULTS

These refractory VT patients (91% male, 66±10 years, ejection fraction 35±11%; 56% ischemic, and 44% nonischemic) had a median of 45 device therapies (shock/antitachycardia pacing) for VT in the 3 to 6 months pre-SERF ablation. The study catheter was used to deliver an average of 10±5 lesions per case, with an average of 430±295 seconds of radiofrequency time, 122±65 minute of catheter use time, and a procedural duration of 4.3±1.3 hours. Acute procedural success was 97% for eliminating the clinical VT. At average follow-up of 5 months (n=32), device therapies were reduced by 89%. Complications included 2 periprocedural deaths: an embolic mesenteric infarct and cardiogenic shock, 2 mild strokes, and a pericardial effusion treated with pericardiocentesis (n=1).

CONCLUSIONS

Intramural heated saline needle ablation showed complete acute and satisfactory mid-term control of difficult VTs failing 1 to 5 prior ablations and drug therapy. Further study is warranted to define safety and longer-term efficacy.

REGISTRATION

URL: https://www.

CLINICALTRIALS

gov; Unique Identifier: NCT03628534 and NCT02994446.

Efficacy and safety of Wenxin Keli combined with metoprolol tartrate in the treatment of premature ventricular contractions: A systematic review and meta-analysis

Background

Wenxin Keli (WXKL) has good clinical value in the treatment of premature ventricular contractions, but there is insufficient evidence to support it. This study evaluates the efficacy and safety of WXKL combined with metoprolol tartrate in the treatment of ventricular premature beats (VPCs).

Methods

We searched seven databases to identify randomized controlled trials (RCTs) for this study. Two reviewers independently screened and extracted the data. The Cochrane Manual criteria were used for methodological quality assessment. Meta-analyses were performed using Review Manager 5.4.1 software. Risk ratios (RR) were used for effect sizes for dichotomous data, demonstrated in effect sizes and 95% confidence intervals (CIs).

Results

A total of 11 RCTs of WXKL combined with metoprolol tartrate in the treatment of premature ventricular contractions were included in this study. Meta-analysis showed that WXKL combined with metoprolol tartrate (treatment group) was more effective than metoprolol tartrate (control group) in improving premature ventricular contractions (RR = 1.32, 95% CI: [1.24, 1.40], P < 0.00001); significantly improved the rate of premature ventricular contractions (RR = 1.32, 95% CI: [1.23, 1.41], P < 0.00001); there was no difference in adverse drug reactions compared with the control group (RR = 0.61, 95% CI: [0.35, 0.1.05], P = 0.08), but the number of adverse reactions (n = 18) was less than that of the control group (n = 32), and the severity was lower than that of the control group. The included studies only mentioned randomization and did not describe the generation of random sequences in detail.

Conclusion

This study found that Wenxin Keli combined with metoprolol tartrate in the treatment of premature ventricular contractions increased the efficacy of the drug, reduced the occurrence of adverse reactions, and reduced the severity of adverse reactions. Due to the quality limitations of the included studies, more high-quality RCTs are needed in the future to provide more evidence for longer-term analyses.

Ablation of Outflow Tract Arrhythmias in Patients With and Without Structural Heart Disease—A Comparative Analysis

Introduction

Catheter ablation of ventricular arrhythmias emerging from the ventricular outflow tracts and adjacent structures is very effective and considered almost curative in patients without structural heart disease (SHD). Outcomes of patients with SHD undergoing ablation of outflow tract arrhythmias are not known.

Methods

Consecutive patients (2019–2021) undergoing catheter ablation of ventricular arrhythmias in a single high-volume center were retrospectively analyzed. Patients with ablation of outflow tract arrhythmias were identified and divided in individuals with and without SHD. Procedural parameters and acute outcome were compared.

Results

We identified 215 patients with outflow tract arrhythmias (35.3% female, mean age 58.3 ± 16.0 years). Of those, 93 (43.3%) had SHD. Patients with SHD and outflow tract arrhythmias were older (65.0 ± 12.8 vs. 53.3 ± 16.3 years; p < 0.001), more often male (82.8 vs. 50.0%; p < 0.001) and had more comorbidities than patients without SHD (arterial hypertension: 62.4 vs. 34.4%, p < 0.001; diabetes: 22.6 vs. 8.2%, p = 0.005; chronic lung disease: 20.4 vs. 7.4%, p = 0.007). Outflow tract arrhythmias in patients with SHD had their origin more often in the left ventricle (68.8 vs. 53.3%, p = 0.025). The acute success rate was similar in both patient groups (93.4 vs. 94.2%, p = 0.781). Patients with SHD were discharged later {median length of hospital stay with SHD 5 [6 (interquartile range)] days, without SHD 2 [4] days, p < 0.001}. Periprocedural complications were numerically more frequent in patients with SHD [with SHD 12 (12.9%), without SHD 8 (6.6%), p = 0.154].

Conclusion

Outflow tract arrhythmia ablation has a high success rate irrespective of the presence of SHD. Longer hospital stay and potentially a higher risk of periprocedural complications should be considered when discussing this treatment option with patients.

Application of EnsiteTM LiveView Function for Identification of Scar-related Ventricular Tachycardia Isthmus

INTRODUCTION

Dynamic display of real-time wavefront activation pattern may facilitate the recognition of reentrant circuits, particularly the diastolic path of ventricular tachycardia (VT).

OBJECTIVE

We aimed to evaluate the feasibility of LiveView Dynamic Display for mapping the critical isthmus of scar-related reentrant VT.

METHODS

Patients with mappable scar-related reentrant VT were selected. The characteristics of the underlying substrates and VT circuits were assessed using HD grid multi-electrode catheter. The VT isthmuses were identified based on the activation map, entrainment, and ablation results. The accuracy of the LiveView findings in detecting potential VT isthmus was assessed.

RESULTS

We studied 18 scar-related reentrant VTs in 10 patients (median age: 59.5 years, 100% male) including 6 and 4 patients with ischemic and non-ischemic cardiomyopathy, respectively. The median VT cycle length was 426 ms (interquartile range: 386-466 ms). Among 590 regional mapping displays, 92.0% of the VT isthmus sites were identified by LiveView Dynamic Display. The accuracy of LiveView for isthmus identification was 84%, with positive and negative predictive values of 54.8% and 97.8%, respectively. The area with abnormal electrograms was negatively correlated with the accuracy of LiveView Dynamic Display (r = -0.506, p = 0.027). The median time interval to identify a VT isthmus using LiveView was significantly shorter than that using conventional activation maps (50.5 [29.8-120] vs. 219 [157.5-400.8] s, p = 0.015).

CONCLUSION

This study demonstrated the feasibility of LiveView Dynamic Display in identifying the critical isthmus of scar-related VT with modest accuracy. This article is protected by copyright. All rights reserved.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

[History of development of ventricular arrhythmias diagnostics]

This review shows historical steps in the development of topical diagnostics for ventricular arrhythmias, the current status of this issue, and the relevance of developing topical, noninvasive electrophysiological cardiac mapping.

Current Guidelines and Clinical Practice

Guidelines exist for monitoring to diagnose and manage patients with several different conditions. Although there have been recent updates to the guidelines, the constantly evolving and advancing nature of the technologies creates a gap at times between the newest monitors, the indications for their use, and the reimbursement by the payers. The key element to the choice of the modality of monitoring remains matching the correct technology to the type, severity, frequency, and duration of the patient's symptoms.

Validation of a Simple Electrocardiographic Algorithm for Detection of Ventricular Tachycardia

Fundamento

O diagnóstico diferencial de taquicardia de QRS largo, entre taquicardia ventricular (TV) ou taquicardia supraventricular com condução aberrante (TSV-A) é algumas vezes difícil de ser feito na sala de emergência.

Objetivo

Avaliar a acurácia de um algoritmo novo e simples para a detecção de TV no eletrocardiograma (ECG) em pacientes com taquicardia de QRS largo.

Métodos

ECGs de 12 derivações para detecção de taquicardia de QRS largo foram obtidos prospectivamente de 120 pacientes durante estudo eletrofisiológico. Seis médicos com diferentes experiências analisaram os ECGs, e fizeram o diagnóstico com base no algoritmo D12V16, que envolve a análise da polaridade predominante do complexo QRS nas derivações I, II, V1 e V6. O diagnóstico foi comparado com os obtidos pelo algoritmo tradicional de Brugada e pelo estudo eletrofisiológico, o qual é considerado padrão ouro. Adotou-se um nível de significância de 5% (p<0,05) nas análises estatísticas.

Resultados

De acordo com o estudo eletrofisiológico, 82 ECGs eram de TV e 38 de TSV-A. Doenças cardíacas estruturais estavam presentes em 71 (86,6%) dos pacientes com TV e em oito (21,1%) com TSV-A. O algoritmo de Brugada teve uma maior sensibilidade global (87,2%), enquanto o algoritmo D12V16 apresentou maior especificidade global (85,1%) para TV. Tanto o algoritmo D12V16 como o de Brugada apresentou um alto valor preditivo positivo (90,9% vs. 85,8%, respectivamente) e acurácia similar (73,8% vs. 81,4%, respectivamente) para o diagnóstico de TV. Nos avaliadores experientes, a acurácia foi maior utilizando o algoritmo de Brugada que o algoritmo D12V16, mas a acurácia dos dois algoritmos foi similar segundo os avaliadores menos experientes.

Conclusão

O algoritmo simplificado pode ser um método útil para reconhecer TV no ECG, principalmente para médicos menos experientes. (Arq Bras Cardiol. 2021; [online].ahead print, PP.0-0)

Clinical significance of J waves with respect to substrate characteristics and ablation outcomes in patients with arrhythmogenic right ventricular cardiomyopathy

AIMS

J-wave syndrome in patients with arrhythmogenic right ventricular cardiomyopathy (ARVC) has been linked to an increased risk of ventricular arrhythmia. We investigated the significance of J waves with respect to substrate manifestations and ablation outcomes in patients with ARVC.

METHODS AND RESULTS

Forty-five patients with ARVC undergoing endocardial/epicardial mapping/ablation were studied. Patients were classified into two groups: 13 (28.9%) and 32 (71.1%) patients with and without J waves, respectively. The baseline characteristics, electrophysiological features, ventricular substrate, and recurrent ventricular tachycardia/fibrillation (VT/VF) were compared. Among the 13 patients with J waves, only the inferior J wave was observed. More ARVC patients with J waves fulfilled the major criteria of ventricular arrhythmias (76.9% vs. 21.9%, P = 0.003). Similar endocardial and epicardial substrate characteristics were observed between the two groups. However, patients with J waves had longer epicardial total activation time than those without (224.7 ± 29.9 vs. 200.8 ± 21.9 ms, P = 0.005). Concordance of latest endo/epicardial activation sites was observed in 29 (90.6%) patients without J waves and in none among those with J waves (P < 0.001). Complete elimination of endocardial/epicardial abnormal potentials resulted in the disappearance of the J wave in 8 of 13 (61.5%) patients. The VT/VF recurrences were not different between ARVC patients with and without J waves.

CONCLUSION

The presence of J waves was associated with the discordance of endocardial/epicardial activation pattern in terms of transmural depolarization discrepancy in patients with ARVC.

Use of the inverse solution guidance algorithm method for RF ablation catheter guidance

INTRODUCTION

We previously introduced the inverse solution guidance algorithm (ISGA) methodology using a Single Equivalent Moving Dipole model of cardiac electrical activity to localize both the exit site of a re-entrant circuit and the tip of a radiofrequency (RF) ablation catheter. The purpose of this study was to investigate the use of ISGA for ablation catheter guidance in an animal model.

METHODS

Ventricular tachycardia (VT) was simulated by rapid ventricular pacing at a target site in eleven Yorkshire swine. The ablation target was established using three different techniques: a pacing lead placed into the ventricular wall at the mid-myocardial level (Type-1), an intracardiac mapping catheter (Type-2), and an RF ablation catheter placed at a random position on the endocardial surface (Type-3). In each experiment, one operator placed the catheter/pacing lead at the target location, while another used the ISGA system to manipulate the RF ablation catheter starting from a random ventricular location to locate the target.

RESULTS

The average localization error of the RF ablation catheter tip was 0.31 ± 0.08 cm. After analyzing approximately 35 cardiac cycles of simulated VT, the ISGA system's accuracy in locating the target was 0.4 cm after four catheter movements in the Type-1 experiment, 0.48 cm after six movements in the Type-2 experiment, and 0.67 cm after seven movements in the Type-3 experiment.

CONCLUSION

We demonstrated the feasibility of using the ISGA method to guide an ablation catheter to the origin of a VT focus by analyzing a few beats of body surface potentials without electro-anatomic mapping.

Myocardial calcification is associated with endocardial ablation failure of post-myocardial infarction ventricular tachycardia

AIMS

In patients with post-myocardial infarction (post-MI) ventricular tachycardia (VT), the presence of myocardial calcification (MC) may prevent heating of a subepicardial VT substrate contributing to endocardial ablation failure. The aims of this study were to assess the prevalence of MC in patients with post-MI VT and evaluate the impact of MC on outcome after endocardial ablation.

METHODS AND RESULTS

In 158 patients, the presence of MC was retrospectively assessed on fluoroscopy recordings in seven standard projections obtained during pre-procedural coronary angiograms. Myocardial calcification, defined as a distinct radiopaque area that moved synchronously with the cardiac contraction, was detected in 30 patients (19%). After endocardial ablation, only 6 patients (20%) with MC were rendered non-inducible compared with 56 (44%) without MC (P = 0.033) and of importance, 8 (27%) remained inducible for the clinical VT [compared with 9 (6%) patients without MC; P = 0.003] requiring therapy escalation. After a median follow-up of 31 months, 61 patients (39%) had VT recurrence and 47 (30%) died. Patients with MC had a lower survival free from the composite endpoint of VT recurrence or therapy escalation at 24-month follow-up (26% vs. 59%; P = 0.003). Presence of MC (HR 1.69; P = 0.046), a lower LV ejection fraction (HR 1.03 per 1% decrease; P = 0.017), and non-complete procedural success (HR 2.42; P = 0.002) were independently associated with a higher incidence of VT recurrence or therapy escalation.

CONCLUSION

Myocardial calcification was present in 19% of post-MI patients referred for VT ablation and was associated with a high incidence of endocardial ablation failure.

Microbubble-Facilitated Ultrasound Catheter Ablation Causes Microvascular Damage and Fibrosis

High-intensity ultrasound (US) ablation produces deeper myocardial lesions than radiofrequency ablation. The presence of intravascular microbubble (MB) contrast agents enhances pulsed-wave US ablation via cavitation-related histotripsy, potentially facilitating ablation in persistently perfused/conducting myocardium. US ablation catheters were developed and tested in the presence of MBs using ex vivo and in vivo models. High-frame-rate videomicroscopy and US imaging of gel phantom models confirmed MB destruction by inertial cavitation. MB-facilitated US ablation in an ex vivo perfused myocardium model generated shallow (2 mm) lesions and, in an in vivo murine hindlimb model, reduced perfusion by 42% with perivascular hemorrhage and inflammation, but no myonecrosis.

Deep sedation as temporary bridge to definitive treatment of ventricular arrhythmia storm

Background:

Electrical storm and incessant ventricular tachycardia (VT) are characterized by the clustering of episodes of VT or ventricular fibrillation (VF) and are associated with a poor prognosis. Autonomic nervous system activity influences VT threshold, and deep sedation may be useful for the treatment of VT emergencies.

Methods:

We reviewed data from conscious patients admitted to our intensive care unit (ICU) due to monomorphic VT, polymorphic VT or VF at our tertiary center between 2010 and 2018.

Results:

A total of 46 conscious patients with recurrent ventricular arrhythmia, refractory to initial treatment, were referred to the ICU. The majority (n = 31) were stabilized on usual care. The remaining treatment-refractory 15 patients (57 years (range 9–74), 80% males, seven with implantable cardioverter-defibrillators) with VT/VF storm (n = 11) or incessant VT (n = 4) due to ischemic heart disease (n = 10), cardiomyopathy (n = 2), primary arrhythmia (n = 2) and one patient post valve surgery, were deeply sedated and intubated. A complete resolution of VT/VF within minutes to hours was achieved in 12 patients (80%), partial resolution in two (13%) and one (7%) patient died due to ventricular free-wall rupture. One patient with recurrent VT episodes needing repeated deep sedation developed necrotic caecum. No other major complications were seen. Thirteen (87%) patients were alive after a mean follow-up of 3.7 years.

Conclusion:

Deep sedation was effective and safe for the temporary management of malignant VT/VF refractory to usual treatment. In emergencies, deep sedation may be widely accessible at both secondary and tertiary centers and a clinically useful bridge to definitive treatment of VT.

Stereotactic Radiotherapy for the Management of Refractory Ventricular Tachycardia: Promise and Future Directions

Ventricular tachycardia (VT) caused by myocardial scaring bears a significant risk of mortality and morbidity. Antiarrhythmic drug therapy (AAD) and catheter ablation remain the cornerstone of VT management, but both treatments have limited efficacy and potential adverse effects. Stereotactic body radiotherapy (SBRT) is routinely used in oncology to treat non-invasively solid tumors with high precision and efficacy. Recently, this technology has been evaluated for the treatment of VT. This review presents the basic underlying principles, proof of concept, and main results of trials and case series that used SBRT for the treatment of VT refractory to AAD and catheter ablation.

Contact feedback improves 1-year outcomes of remote magnetic navigation-guided ischemic ventricular tachycardia ablation

INTRODUCTION

Remote magnetic navigation (RMN)-guided catheter ablation (CA) is a feasible treatment option for patients presenting with ischemic ventricular tachycardia (VT). Catheter-tissue contact feedback, enhances lesion formation and may consequently improve CA outcomes. Until recently, contact feedback was unavailable for RMN-guided CA. The novel e-Contact Module (ECM) was developed to continuously monitor and ensure catheter-tissue contact during RMN-guided CA.

OBJECTIVE

The present study aims to evaluate the effect of ECM implementation on acute and long-term outcomes in RMN-guided ischemic VT ablation.

METHOD

This retrospective, two-center study included consecutive ischemic VT patients undergoing RMN-guided CA from 2010 to 2017. Baseline clinical data, procedural data, including radiation times, and acute success rates were compared between CA procedures performed with ECM (ECM+) and without ECM (ECM-). One-year VT-free survival was analyzed using Cox-proportional hazards models, adjusting for potential confounders: age, left ventricular function, VT inducibility at baseline and substrate based ablation strategy.

RESULTS

The current study included 145 patients (ECM+ N = 25, ECM- N = 120). Significantly lower fluoroscopy times were observed in the ECM+ group (9.5 (IQR 5.3-13.5) versus 12.5 min (IQR 8.0-18.0), P = 0.025). Non-inducibility of the clinical VT at the end of procedure was observed in 92% ECM+ versus 72% ECM- patients (P = 0.19). ECM guidance was associated with significantly lower VT-recurrence rates during 1-year follow-up (16% ECM+ versus 40% ECM-; multivariable HR 0.29, 95%-CI 0.10-0.69, P = 0.021, reference group: ECM-).

CONCLUSION

Contact feedback by the ECM further decreases fluoroscopy exposure and improves VT-free survival in RMN-guided ischemic VT ablation.

Introducing a novel catheter-tissue contact feedback feature in robotic navigated catheter ablation: Utility, feasibility, and safety

Background

The quality of catheter–tissue contact is one of the most important determinants of catheter ablation (CA) success. The absence of catheter–tissue contact feedback has been regarded a major limitation of remote magnetic navigation (RMN)–guided CA. The e-Contact module (ECM) is a novel feature designed for RMN that measures the quality of catheter–tissue contact.

Objective

The purpose of this study was to describe the first clinical experience with this feature and to test its effect on procedural parameters and interference with other ablation equipment during CA procedures as well as its safety.

Methods

This was a prospective, single-center, 2-phase study investigating ECM use during complex RMN procedures in 30 patients. Impact of ECM on procedural parameters was evaluated in the feasibility phase (FP), and its interference with other equipment was tested in the interference phase (IP) using pacing maneuvers at 3 randomly selected right atrial sites. Intracardiac electrograms were evaluated for disturbances by 2 independent electrophysiologists.

Results

For FP, mean procedural time was 162 ± 66 minutes, fluoroscopy time 21 ± 9 minutes, and ablation time 34 ± 21 minutes. For IP, no significant differences in pacing capture or thresholds were found (ECM– vs ECM+: site 1: 2.05 vs 2.21 mA; P = .320; site 2: 2.15 vs 2.12 mA; P = .873; site 3: 2.51 vs 2.50 mA; P = .976). Electrogram disturbances did not significantly differ between ECM– and ECM+. No adverse events were reported.

Conclusion

The ECM is a novel catheter–tissue contact technology designed for RMN-guided CA. Our study suggests that this feature is feasible and does not interfere with other electrophysiology equipment while maintaining an excellent safety profile.

Islets of heterogeneous myocardium within the scar in cardiac magnetic resonance predict ventricular tachycardia after myocardial infarction

INTRODUCTION

We assessed findings in cardiac magnetic resonance (CMR) as predictors of ventricular tachycardia (VT) after myocardial infarction (MI), which could allow for more precise identification of patients at risk of sudden cardiac death.

METHODS

Forty-eight patients after prior MI were enrolled and divided into two groups: with (n = 24) and without (n = 24) VT. VT was confirmed by electrophysiological study and exit site was estimated based on 12-lead electrocardiogram. All patients underwent CMR with late gadolinium enhancement.

RESULTS

The examined groups did not differ significantly in clinical and demographical parameters (including LV ejection fraction). There was a significant difference in the infarct age between the VT and non-VT group (15.8 ± 8.4 vs 7.1 ± 6.7 years, respectively; P = .002), with the cut-off point at the level of 12 years. In the scar core, islets of heterogeneous myocardium were revealed. They were defined as areas of potentially viable myocardium within or adjacent to the core scar. The number of islets was the strongest independent predictor of VT (odds ratio [OR], 1.42; confidence interval [CI], 1.17-1.73), but total islet size and the largest islet area were also significantly higher in the VT group (OR, 1.04; CI, 1.02-1.07 and OR, 1.16; CI, 1.01-1.27, respectively). Myocardial segments with fibrosis forming 25%-75% of the ventricular wall were associated with a higher incidence of VT (7.5 ± 2.1 vs 5.7 ± 2.6; P = .014). Three-dimension CMR reconstruction confirmed good correlation of the location of the islets/channels with VT exit site during electroanatomical mapping in five cases.

CONCLUSIONS

The identification and quantification of islets of heterogeneous myocardium within the scar might be useful for predicting VT in patients after MI.

Left ventricular aneurysmectomy in a young female with pseudoaneurysm of unknown etiology

A left ventricular pseudoaneurysm is formed when there is free wall rupture of the myocardial wall with discontinuity and roof covered by pericardium mural thrombus or fibrous tissue without any myocardium. A left ventricular pseudoaneurysm is a rare and life-threatening event. We report a young 22-year-old female with unknown etiology of a pseudoaneurysm, who was previously managed as a psychiatric case and for musculoskeletal pain. On subsequent investigation and confirmation with cardiac magnetic resonance imaging, aneurysmectomy was done. This is a rare case in a young 22-year-old woman with a ventricular pseudoaneurysm of unknown etiology. Considering the high risk for rupture of a ventricular pseudoaneurysm, surgical resection was mandatory with no complications intra- and post-procedure.

Catheter Ablation in Patients With Cardiogenic Shock and Refractory Ventricular Tachycardia

BACKGROUND

There is paucity of data regarding radiofrequency ablation for ventricular tachycardia (VT) in patients with cardiogenic shock and concomitant VT refractory to antiarrhythmic drugs on mechanical support.

METHODS

Patients undergoing VT ablation at our center were enrolled in a prospectively maintained registry and screened for the current study (2010-2017).

RESULTS

All 21 consecutive patients with cardiogenic shock and concomitant refractory ventricular arrhythmia undergoing bailout ablation due to inability to wean off mechanical support were included. Median age was 61 years, 86% were men, median left ventricular ejection fraction was 20%, 81% had ischemic cardiomyopathy, and PAINESD score was 18±5. The type of mechanical support in place before the procedure was intra-aortic balloon pump in 14 patients (67%), Impella CP in 2, extracorporeal membrane oxygenation in 2, extracorporeal membrane oxygenation and intra-aortic balloon pump in 2, and extracorporeal membrane oxygenation and Impella CP in 1. Endocardial voltage maps showed myocardial scar in 19 patients (90%). The clinical VTs were inducible in 13 patients (62%), whereas 6 patients had premature ventricular contraction-induced ventricular fibrillation/VT (29%), and VT could not be induced in 2 patients (9%). Activation mapping was possible in all 13 with inducible clinical VTs. Substrate modification was performed in 15 patients with scar (79%). After ablation and scar modification, the arrhythmia was noninducible in 19 patients (91%). Seventeen (81%) were eventually weaned off mechanical support successfully, but 6 (29%) died during the index admission from persistent cardiogenic shock. Patients who had ventricular arrhythmia and cardiogenic shock on presentation had a trend toward lower in-hospital mortality compared with those who presented with cardiogenic shock and later developed ventricular arrhythmia.

CONCLUSIONS

Bailout ablation for refractory ventricular arrhythmia in cardiogenic shock allowed successful weaning from mechanical support in a large proportion of patients. Mortality remains high, but the majority of patients were discharged home and survived beyond 1 year.

Clinical, procedural and long-term outcome of ischemic VT ablation in patients with previous anterior versus inferior myocardial infarction

Background

Outcome of ischemic VT ablation may differ between patients with previous myocardial infarction (MI) in relation to infarct localization.

Methods

We analyzed procedural data, acute and long-term outcomes of 152 consecutive patients (139 men, mean age 67 ± 9 years) with previous anterior or inferior MI who underwent ischemic VT ablation at our institution between January 2010 and October 2015.

Results

More patients had a history of inferior MI (58%). Mean ejection fraction was significantly lower in anterior MI patients (28 ± 10% vs. 34 ± 10%, p < 0.001). NYHA class and presence of comorbidities were not different between the groups. Indication for the procedure was electrical storm in 43% of patients, and frequent implantable cardioverter defibrillator (ICD) therapies in 57%, and did not differ significantly between anterior and inferior MI patients. A mean of 3 ± 2 VT morphologies were inducible, with a trend towards more VT in the anterior MI group (3.1 ± 2.2 vs. 2.6 ± 1.9, p = 0.18). Procedural parameters and acute success did not differ between the groups. During a mean follow-up of 3 ± 2 years, more anterior MI patients had undergone a re-ablation (49% vs. 33%, p = 0.09, Chi-square test). There was a trend towards more ICD shocks in patients with previous anterior MI (46% vs. 34%). After adjusting for risk factors and ejection fraction, multivariable Cox regression analyses showed no significant difference in mortality (p = 0.78) and cardiovascular mortality between infarct localizations (p = 0.6).

Conclusion

Clinical characteristics of patients with anterior and inferior MI are similar except for ejection fraction. Patients with inferior MI appear to have better outcome regarding survival, ICD shocks and re-ablation, but this appears to be related to better ejection fraction when compared with anterior MI.

Catheter ablation of ventricular arrhythmias and in-hospital mortality: insights from the German-wide Helios hospital network of 5052 cases

AIMS

Catheter ablation (CA) of ventricular arrhythmias is one of the most challenging electrophysiological interventions with an increasing use over the last years. Several benefits must be weighed against the risk of potentially life-threatening complications which necessitates a steady reevaluation of safety endpoints. Therefore, the aims of this study were (i) to investigate overall in-hospital mortality in patients undergoing such procedures and (ii) to identify variables associated with in-hospital mortality in a German-wide hospital network.

METHODS AND RESULTS

Between January 2010 and September 2018, administrative data provided by 85 Helios hospitals were screened for patients with main or secondary discharge diagnosis of ventricular tachycardia (VT) or premature ventricular contractions (PVCs) in combination with an arrhythmia-related CA using ICD- and OPS codes. In 5052 cases (mean age 60.9 ± 14.3 years, 30.1% female) of 30 different hospitals, in-hospital mortality was 1.27% with a higher mortality in patients ablated for VT (1.99%, n = 2, 955) compared to PVC (0.24%, n = 2, 097, P < 0.01). Mortality rates were 2.06% in patients with ischaemic heart disease (IHD, n = 2, 137), 1.47% in patients with non-ischaemic structural heart disease (NIHD, n = 1, 224), and 0.12% in patients without structural heart disease (NSHD, n = 1, 691). Considering different types of hospital admission, mortality rates were 0.35% after elective (n = 2, 825), 1.60% after emergency admission/hospital transfer <24 h (n = 1, 314) and 3.72% following delayed hospital transfer >24 h after initial admission (n = 861, P < 0.01 vs. elective admission and emergency admission/hospital transfer <24 h). In multivariable analysis, a delayed hospital transfer >24 h [odds ratio (OR) 2.28, 95% confidence interval (CI) 1.59-3.28, P < 0.01], the occurrence of procedure-related major adverse events (OR 6.81, 95% CI 2.90-16.0, P < 0.01), Charlson Comorbidity Index (CCI, OR 2.39, 95% CI 1.56-3.66, P < 0.01) and its components congestive heart failure (OR 8.04, 95% CI 1.71-37.8, P < 0.01), and diabetes mellitus (OR 1.59, 95% CI 1.13-2.22, P < 0.01) were significantly associated with in-hospital death.

CONCLUSIONS

We reported in-hospital mortality rates after CA of ventricular arrhythmias in the largest multicentre, administrative dataset in Germany which can be implemented in quality management programs. Aside from comorbidities, a delayed hospital transfer to a CA performing centre is associated with an increased in-hospital mortality. This deserves further studies to determine the optimal management strategy.

Ventricular Tachycardia Ablation in Non-ischemic Cardiomyopathy

Non-ischemic cardiomyopathies are a heterogeneous group of diseases of the myocardium that have a distinct proclivity to ventricular arrhythmias. Of these, ventricular tachycardias pose significant management challenges with the risk of sudden cardiac death and morbidity from multiple causes. Catheter ablation of ventricular tachycardias is becoming an increasingly utilised intervention that has been found to have significant benefits with improving symptoms, reducing anti-arrhythmic drug burden and debilitating device therapies, thereby improving quality of life. Nonetheless, the approach to the ablation of ventricular tachycardias in non-ischemic cardiomyopathies is governed heavily by the disease process, with several distinct differences from ischemic cardiomyopathy including a preponderance to epicardial and deep intramural substrate. This contemporary review aims to present the various disease processes within non-ischemic cardiomyopathies, catheter ablation techniques which have been developed to target ventricular tachycardia and more novel adjunctive therapeutic measures.

Role of Contact Force Sensing in Catheter Ablation of Cardiac Arrhythmias: Evolution or History Repeating Itself?

Adequate catheter-tissue contact facilitates efficient heat energy transfer to target tissue. Tissue contact is thus critical to achieving lesion transmurality and success of radiofrequency (RF) ablation procedures, a fact recognized more than 2 decades ago. The availability of real-time contact force (CF)-sensing catheters has reinvigorated the field of ablation biophysics and optimized lesion formation. The ability to measure and display CF came with the promise of dramatic improvement in safety and efficacy; however, CF quality was noted to have just as important an influence on lesion formation as absolute CF quantity. Multiple other factors have emerged as key elements influencing effective lesion formation, including catheter stability, lesion contiguity and continuity, lesion density, contact homogeneity across a line of ablation, spatiotemporal dynamics of contact governed by cardiac and respiratory motion, contact directionality, and anatomic wall thickness, in addition to traditional ablation indices of power and RF duration. There is greater appreciation of surrogate markers as a guide to lesion formation, such as impedance fall, loss of pace capture, and change in unipolar electrogram morphology. In contrast, other surrogates such as tactile feedback, catheter motion, and electrogram amplitude are notably poor predictors of actual contact and lesion formation. This review aims to contextualize the role of CF sensing in lesion formation with respect of the fundamental principles of biophysics of RF ablation and summarize the state-of-the-art evidence behind the role of CF in optimizing lesion formation.

Agreement between gadolinium-enhanced cardiac magnetic resonance and electro-anatomical maps in patients with non-ischaemic dilated cardiomyopathy and ventricular arrhythmias

AIMS

We sought to investigate the overlap between late gadolinium enhancement (LGE) in cardiac magnetic resonance (CMR) and electro-anatomical maps (EAM) of patients with non-ischaemic dilated cardiomyopathy (NIDCM) and how it relates with the outcomes after catheter ablation of ventricular arrhythmias (VA).

METHODS AND RESULTS

We identified 50 patients with NIDCM who received CMR and ablation for VA. Late gadolinium enhancement was detected in 16 (32%) patients, mostly in those presenting with sustained ventricular tachycardia (VT): 15 patients. Low-voltage areas (<1.5 mV) were observed in 23 (46%) cases; in 7 (14%) cases without evidence of LGE. Using a threshold of 1.5 mV, a good and partially good agreement between the bipolar EAM and LGE-CMR was observed in only 4 (8%) and 9 (18%) patients, respectively. With further adjustments of EAM to match the LGE, we defined new cut-off limits of median 1.5 and 5 mV for bipolar and unipolar maps, respectively. Most VT exits (12 out of 16 patients) were found in areas with LGE. VT exits were found in segments without LGE in two patients with VT recurrence as well as in two patients without recurrence, P = 0.77. In patients with VT recurrence, the LGE volume was significantly larger than in those without recurrence: 12% ± 5.8% vs. 6.9% ± 3.4%; P = 0.049.

CONCLUSIONS

In NIDCM, the agreement between LGE and bipolar EAM was fairly poor but can be improved with adjustment of the thresholds for EAM according to the amount of LGE. The outcomes were related to the volume of LGE.

An Economic Analysis of the Systematic Use of Mapping Systems during Catheter Ablation Procedures: Single Center Experience

INTRODUCTION

In this study we estimated the cost-effectiveness of adopting 3D Nonfluoroscopic Mapping Systems (NMSs) for catheter ablation (CA).

METHODS

This study includes patients who underwent supraventricular tachycardia (SVT) CA and atrial fibrillation (AF) CA from 2007 to 2016. A comparison was conducted between a reference year (2007) and the respective years for the two types of procedure in which the maximum optimization of patients' exposure using NMSs was obtained. We compared the data of all SVT CA performed solely using fluoroscopy in 2007 (Group I) and all SVT CA procedures performed using fluoroscopy together with an NMS in 2011 (Group II). There was also an important comparison made between AF CA procedures performed in 2007 (Group III) and AF CA in 2012 (Group IV), where patients' treatment in both years included the use of an NMS but where the software and hardware versions of the NMS were different. Two cost-effectiveness analyses were carried out. The first method was based on the alpha value (AV): the AV is a monetary reference value of avoided unit of exposure and is expressed as $/mansievert. The second one was based on the value of a statistical life (VSL): the VSL does not represent the cost value of a person's life, but the amount that a community would be willing to pay to reduce the risk of a person's death. The costs estimated from these two methods were compared to the real additional cost of using an NMS during that type of procedure in our EP Lab.

RESULTS

The use of NMS reduced the effective dose of about 2.3 mSv for SVT and 23.8 mSv for AF CA procedures. The use of NMS, applying directly AV or VSL values, was not cost-effective for SVT CA for the most countries, whereas the use of an NMS during an AF CA seemed to be cost-effective for most of them.

CONCLUSIONS

In our analysis the cost-effectiveness of the systematic use of NMSs strongly depended on the AV and VSL values considered. Nonetheless, the approach seemed to be cost-effective only during AF CA procedures.

Late fractionated potentials in catheter ablation for right ventricular outflow tract ventricular arrhythmias

BACKGROUND

Endocardial late fractionated potentials during sinus rhythm mapping may reflect abnormal "subendocardial" substrates associated with right ventricular outflow tract (RVOT) ventricular arrhythmias (VAs). The aim of this study was to explore the clinical outcomes of catheter ablation guided by these late fractionated potentials for RVOT VAs in patients without structural heart disease.

METHODS

From January 2016 to March 2018, 28 patients underwent catheter ablation for RVOT premature ventricular contractions (PVCs) or ventricular tachycardia (VT), guided by the EnSite NavX or Velocity V5.0 three-dimensional mapping system (Abbott, St. Paul, MN, USA). Among them, 10 patients (35.7%) were found to have endocardial late fractionated potentials during sinus rhythm mapping (Group 1). Group 2 was composed of 18 patients in whom no endocardial late fractionated potentials were seen. The burden of VAs, acute procedural success, and 3-month clinical outcomes were analyzed.

RESULTS

The average duration of late fractionated potentials after the end of QRS during sinus rhythm mapping in group 1 was 45.00 ± 17.15 ms. Baseline demographics and morphology and burden of PVCs were similarly distributed between both groups. Group 1 had higher acute procedural success compared to group 2 (100% vs 66.7%; P = .039). Moreover, at 3-month follow-up, group 1 had lower total PVCs (49 (1-5986) versus 4316 (1-23231); P = .048), PVC burden (0% (0-5.9) vs 4.3% (0-18.9); P = .055), and higher clinical success (100% vs 55.6%; P = .025) compared to group 2.

CONCLUSION

The identification and elimination of endocardial late fractionated potentials during sinus rhythm mapping could improve the acute success and short-term outcomes of ablation for RVOT VAs.

High burden of premature ventricular contractions in structurally normal hearts: To worry or not in pediatric patients?

BACKGROUND

There is paucity of data regarding the significance of high percentage of premature ventricular contractions (PVCs) in healthy children and their impact on left ventricular (LV) function and the risk of ventricular arrhythmias. The purpose of this study was to assess the prevalence of LV systolic dysfunction in children with frequent PVCs and determine whether PVC characteristics were predictive of LV dysfunction.

METHODS

We performed a single-center retrospective review to examine the prevalence of PVC-induced cardiomyopathy and natural history of PVC burden in children with frequent PVCs. Children aged 6 months-21 years with PVCs noted on 24-hr Holter monitoring studies were enrolled. The four categories included those with a PVC burden of >10%, 10%-20%, and those with more than 20% PVC burden.

RESULTS

A total of 134 children were included, 65 with more than 10% PVCs and 31 with more than 20% PVCs. Median age of the patients was 10.5 years (IQR 6.1-14.8 years), with 79 males (54.5%). Median PVC burden was 8.7% (IQR 4.2%-16.9%) with median follow-up of 2.8 years (IQR 1.2-4.6 years). During 2.8 years (1.3-4.3 years) of follow-up, the PVC burden decreased by 67% of baseline PVC burden in those who did not undergo any intervention. There were no deaths.

CONCLUSION

PVCs in children with structurally normal hearts are associated with a relatively benign course, with trend toward spontaneous resolution.

[Premature ventricular contractions and tachycardia in a structurally normal heart : Idiopathic PVC and VT]

Premature ventricular contractions (PVC) are a common, often incidental and mostly benign finding. Treatment is indicated in frequent and symptomatic PVC or in cases of worsening of left ventricular function. Idiopathic ventricular tachycardia (VT) is mostly found in patients with a structurally healthy heart. These PVC/VT usually have a focal origin. The most likely mechanism is delayed post-depolarization. Localization of the origin is based on the creation of an activation map with or without combination of pace mapping. Idiopathic PVC/VT are most frequently located on the outflow tracts of the right and left ventricles, including the aortic root. Other typical locations include the annulus of the tricuspid or mitral valve, papillary muscles and Purkinje fibers. Catheter ablation is an alternative to antiarrhythmic medication in symptomatic monomorphic PVC/VT. The success rate is good whereby mapping and ablation can often represent a challenge. This article is the fifth part of a series dedicated to specific advanced training in the field of special rhythmology and invasive electrophysiology. It describes the pathophysiological principles, types and typical findings that can be obtained during an electrophysiological investigation.

Personalized Cardiac Computational Models: From Clinical Data to Simulation of Infarct-Related Ventricular Tachycardia

In the chronic stage of myocardial infarction, a significant number of patients develop life-threatening ventricular tachycardias (VT) due to the arrhythmogenic nature of the remodeled myocardium. Radiofrequency ablation (RFA) is a common procedure to isolate reentry pathways across the infarct scar that are responsible for VT. Unfortunately, this strategy show relatively low success rates; up to 50% of patients experience recurrent VT after the procedure. In the last decade, intensive research in the field of computational cardiac electrophysiology (EP) has demonstrated the ability of three-dimensional (3D) cardiac computational models to perform in-silico EP studies. However, the personalization and modeling of certain key components remain challenging, particularly in the case of the infarct border zone (BZ). In this study, we used a clinical dataset from a patient with a history of infarct-related VT to build an image-based 3D ventricular model aimed at computational simulation of cardiac EP, including detailed patient-specific cardiac anatomy and infarct scar geometry. We modeled the BZ in eight different ways by combining the presence or absence of electrical remodeling with four different levels of image-based patchy fibrosis (0, 10, 20, and 30%). A 3D torso model was also constructed to compute the ECG. Patient-specific sinus activation patterns were simulated and validated against the patient's ECG. Subsequently, the pacing protocol used to induce reentrant VTs in the EP laboratory was reproduced in-silico. The clinical VT was induced with different versions of the model and from different pacing points, thus identifying the slow conducting channel responsible for such VT. Finally, the real patient's ECG recorded during VT episodes was used to validate our simulation results and to assess different strategies to model the BZ. Our study showed that reduced conduction velocities and heterogeneity in action potential duration in the BZ are the main factors in promoting reentrant activity. Either electrical remodeling or fibrosis in a degree of at least 30% in the BZ were required to initiate VT. Moreover, this proof-of-concept study confirms the feasibility of developing 3D computational models for cardiac EP able to reproduce cardiac activation in sinus rhythm and during VT, using exclusively non-invasive clinical data.

Extensive Use of 3D Nonfluoroscopic Mapping Systems for Reducing Radiation Exposure during Catheter Ablation Procedures: An Analysis of 10 Years of Activity

Purpose

3D nonfluoroscopic mapping systems (NMSs) are generally used in the catheter ablation (CA) of complex ventricular and atrial arrhythmias. The aim of this study was to evaluate the efficacy, safety, and long-term effect of the extended, routine use of NMSs for CA.

Methods

Our study involved 1028 patients who underwent CA procedures from 2007 to 2016. Initially, CA procedures were performed mainly with the aid of fluoroscopy. From October 2008, NMSs were used for all procedures.

Results

The median fluoroscopy time of the overall CA procedures fell by 71%: from 29.2 min in 2007 to 8.4 min in 2016. Over the same period, total X-ray exposure decreased by 65%: from 58.18 Gy⁎cm² to 20.19 Gy⁎cm². This reduction was achieved without prolonging the total procedure time. In AF CA procedures, the median fluoroscopy time fell by 85%, with an 86% reduction in total X-ray exposure. In SVT CA procedures, the median fluoroscopy time fell by 93%, with a 92% reduction in total X-ray exposure. At the end of the follow-up period, the estimated probability of disease-free survival was 67.7% at 12 months for AF CA procedures and 97.2% at 3 months for SVT CA, without any statistically significant difference between years.

Conclusions

Our study shows the feasibility of using NMSs as the main imaging modality to guide CA. The extended, routine use of NMSs dramatically reduces radiation exposure, with only slight fluctuations due to the process of acquiring experience on the part of untrained operators, without affecting disease-free survival.