Structural Heart Disease Ventricular Tachycardia Research Articles

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.

PO-05-068 MAJOR VASCULAR COMPLICATIONS IN A LARGE COHORT OF PATIENTS UNDERGOING CATHETER ABLATION FOR VPB/VT IN A HIGH-VOLUME, TERTIARY EP CENTER

Catheter ablation is an established treatment method both in patients with idiopathic premature ventricular complexes (PVC) or ventricular tachycardia (VT) and in structural heart disease (SHD) VT. Major vascular complications (MVCs) are the most frequent in these populations. A retrospective study investigating the incidence of MVCs in large-volume, specialized VT center and analyzing their predictors. We included PVC/VT patients who had their first ablation procedure between August 2006 - December 2020. The procedures were performed under conscious sedation except for patients who were on mechanical ventilation because of hemodynamical or electrical instabilit. Activation mapping supported by an electroanatomic mapping system was used in idiopathic cases. In SHD, substrate mapping using an electroanatomic mapping system and pacemapping was employed as a prerequisite for complete substrate modification during spontaneous rhythm or pacing. Activation and entrainment mapping for well-tolerated VTs were rarely used. The goal of ablation was to abolish all inducible VTs. A specific institutional tracking system for complications of invasive procedures was used to collect all periprocedural complications that were subsequently adjudicated. MVCs were defined as those that result in permanent injury or death, require intervention or treatment, prolong hospitalization (>48 hrs) or require new hospitalization. Idiopathic PVC/VT ablation was performed in 656 pts (males: 50%, age: 51 ± 17 years, re-ablations: 15%). SHD VT was ablated in 1637 pts (males: 88%, age: 63 ± 13 years, re-ablations: 30%, ischemic cardiomyopathy: 65%, left ventricular ejection fraction: 34 ± 13%, electrical storm: 24%). In idiopathic PVC/VT, MVCs were observed in 2.4 % (4.0% in males vs. 0.9% in females, P <0.01). In SHD, the rate of MVCs reached 3.5 % (2.8% in males vs. 9.4% in females, P <0.00001). Based on the multivariable regression model, the composite risk score to predict MVCs was proposed that was calculated as a sum of risk points for age (0, 1, 2, and 3 points for <50, 50–59, 60–69, and ≥70 years, respectively), female gender (2 points), and serum creatinine >1.3mg/dL (2 points), range 0–7 (Figure). While in an idiopathic setting, MVCs were more frequent in males, which may reflect a higher proportion of more complex LV ablations and arterial access, there was a significant female predominance in MVCs in SHD. The composite risk score predicts the risk of MVCs independently of VT cause.

Clinical and Electrophysiologic Characteristics of Ventricular Tachycardias from the Basal Septum in Structural Heart Disease

Background The basal septum is a common source of ventricular tachycardia (VT) in patients with structural heart disease (SHD).ObjectiveWe describe the clinical and electrophysiologic characteristics of basal septal VTs in SHD patients.MethodsData from 312 consecutive SHD patients undergoing catheter ablation of ventricular arrhythmias were reviewed.ResultsThirty-three basal-septal VTs in 31 patients (mean age 67.4{plus minus}14.2 years, left ventricular [LV] ejection fraction [EF] 42{plus minus}15%) were identified. Patients with VTs with LV basal-septal breakthrough were more likely to have ischemic cardiomyopathy and a lower LVEF; right ventricular basal-septal VT patients were more likely to have sarcoidosis or right ventricular cardiomyopathy of unknown significance, with a higher LVEF. Atrioventricular block was present in 45% and intraventricular block including persistent bi-ventricular pacing in 77%. Unipolar scar was larger than bipolar scar (area 18.8{plus minus}19.4% vs. 12.7{plus minus}14.6%, P<0.001). VTs with a right bundle branch block (BBB) morphology and S wave in V6 with positive V3/V4 polarity consistently indicated an LV basal-septal breakthrough. Inferior limb-lead discordance with a right BBB morphology and reverse pattern break in V2 were identified in LV basal infero-septal origin in 3 patients respectively. VT non-inducibility was achieved in 55% and VT recurred in 42% of patients after a single procedure, however, VT burden was significantly reduced after ablation (59 episodes pre vs. 2 episodes post, P=0.02).ConclusionBasal-septal VTs in SHD have a distinct clinical, electrocardiographic, and electrophysiologic profile depending on the breakthrough site, accompanied by a deep intramural septal substrate that limits procedural success after catheter ablation.

Impact of a high-density grid catheter on long-term outcomes for structural heart disease ventricular tachycardia ablation

BackgroundSubstrate mapping has highlighted the importance of targeting diastolic conduction channels and late potentials during ventricular tachycardia (VT) ablation. State-of-the-art multipolar mapping catheters have enhanced mapping capabilities. The purpose of this study was to investigate whether long-term outcomes were improved with the use of a HD Grid mapping catheter combining complementary mapping strategies in patients with structural heart disease VT.MethodsConsecutive patients underwent VT ablation assigned to either HD Grid, Pentaray, Duodeca, or point-by-point (PbyP) RF mapping catheters. Clinical endpoints included recurrent anti-tachycardia pacing (ATP), appropriate shock, asymptomatic non-sustained VT, or all-cause death.ResultsSeventy-three procedures were performed (33 HD Grid, 22 Pentaray, 12 Duodeca, and 6 PbyP) with no significant difference in baseline characteristics. Substrate mapping was performed in 97% of cases. Activation maps were generated in 82% of HD Grid cases (Pentaray 64%; Duodeca 92%; PbyP 33% (p = 0.025)) with similar trends in entrainment and pace mapping. Elimination of all VTs occurred in 79% of HD Grid cases (Pentaray 55%; Duodeca 83%; PbyP 33% (p = 0.04)). With a mean follow-up of 372 ± 234 days, freedom from recurrent ATP and shock was 97% and 100% respectively in the HD Grid group (Pentaray 64%, 82%; Duodeca 58%, 83%; PbyP 33%, 33% (log rank p = 0.0042, p = 0.0002)).ConclusionsThis study highlights a step-wise improvement in survival free from ICD therapies as the density of mapping capability increases. By using a high-density mapping catheter and combining complementary mapping strategies in a strict procedural workflow, long-term clinical outcomes are improved.

Renal Denervation for the Management of Refractory Ventricular Arrhythmias: ASystematicReview.

The authors performed a systematic review and meta-analysis to determine the efficacy of renal denervation (RDN) in patients with refractory ventricular arrhythmias (VA) or electrical storm (ES). Although catheter ablation is efficacious for the treatment of structural heart disease ventricular tachycardia (VT), there are proportion of patients who have refractory VT despite multiple procedures. In this setting, novel adjunctive therapies such as renal denervation have been performed. A systematic review of published data was performed. Studies that evaluated patients undergoing RDN for VA or ES were included. Outcome measures of VA, sudden cardiac death, ES, or device therapy were required. Case reports, editorials, and conference presentations were excluded. Random effects meta-analysis was conducted to explore change or final mean values in the study outcomes. A total of 328 articles were identified by the literature search. Seven studies met the eligibility criteria and were included in the systematic review, with a total of 121 pooled patients. The weighted mean age was 63.8 ± 13.1 years, ejection fraction 30.5 ± 10.3%, 76% were men, 99% were on a beta blocker, 79% were on amiodarone, 46% had previously undergone catheter ablation, and 8.3% had previously undergone cardiac sympathetic denervation. Meta-analysis demonstrated a significant effect of RDN in reducing implantable cardiac defibrillator therapies, with a standardized mean difference (SMD) of-3.11 (p<0.001). RDN also reduced the number of VA episodes (SMD-2.13; p<0.001), antitachycardia pacing episodes (SMD-2.82; p=0.002), and shocks (SMD-2.82; p=0.002). RDN is an effective treatment for refractory VAs and ES, although randomized data are lacking.

P1381Improved outcome in ablation of ventricular tachycardia in patients with structural heart disease under general anaesthetic

Abstract Background Catheter ablation is an important adjunct to device implantation for secondary prevention of ventricular tachycardia (VT). However, several factors may influence the success of ablations in terms of long-term freedom from VT recurrence. A thus far little examined factor is the use of general anaesthetic (GA) versus conscious sedation during the procedure, which has been shown to improve outcomes in persistent atrial fibrillation (AF) ablation. Methods Patients with structural heart disease VT undergoing ablations from January 2015 to March 2019 were retrospectively followed up at a single centre. End points were recurrent VT or device therapy (shock or anti-tachycardia pacing) at one year. Hazard ratios (HR) were generated using a multivariate Cox-regression proportional hazards model including variables of age at ablation, sex, amiodarone use at time of ablation, scar age, left ventricular ejection fraction, use of GA, and diagnosis of: diabetes mellitus (DM), hypertension (HTN), renal impairment or AF. Results 79 patients (74 male, mean age 68.2+/- 10.3 years) were included. A substrate-based strategy of late potential ablation was employed. 69 had ischaemic and 10 had non-ischaemic cardiomyopathy. Mean scar age was 13.8 +/- 9.8 years; EF was 40-50% in 27 patients, 30-40% in 26 and &amp;lt; 30% in 26. 37 patients had implantable cardioverter defibrillators and 30 had cardiac resynchronisation therapy (CRT) defibrillator devices, 1 had a CRT- pacemaker device and 4 had dual chamber pacemakers. Comorbidities were: DM (16), HTN (31), renal impairment (13), AF (31). 62 patients (79.5%) were on amiodarone at the time of ablation. Mean procedure duration was 234.8 +/- 44.5 min and mean radiofrequency energy application time was 2247 +/- 862 s. 61 were first procedures and 18 were repeat procedures. One patient suffered a complication of groin haematoma. 62 patients (78.5%) underwent VT ablation under GA and 17 (21.5%) under sedation of midazolam and fentanyl. Patient characteristics did not differ between groups. Significant factors which increased freedom from VT recurrence or device therapy were HTN (88.9% vs 59.4%, HR 0.72, 95% confidence interval (CI): 0.007-0.75, p= 0.028), amiodarone treatment (50.0% vs 76.3%, HR 0.036, 95% CI: 0.003-0.404, p = 0.036) and ablation under GA rather than sedation (50.0% vs 75.0%, HR 0.055, 95% CI: 0.006-0.495, p = 0.01) (Fig 1). Conclusions In patients with structural heart disease undergoing VT ablation, outcomes are improved with the use of GA over conscious sedation. Abstract Figure 1

Focal Ventricular Tachycardias in Structural Heart Disease: Prevalence, Characteristics, and Clinical Outcomes After Catheter Ablation.

This study sought to summarize the procedural characteristics and outcomes of patients with structural heart disease (SHD) who have focal ventricular tachycardia (VT). Scar-mediated re-entry is the predominant mechanism of VT in SHD. Some SHD patients may have a focal VT mechanism that remains poorly described. An extended induction protocol incorporating programmed electrical stimulation, right ventricular burst pacing and isoprenaline was used to elucidate both re-entrant and focal VT mechanisms. Eighteen of 112 patients (16%) with SHD undergoing VT ablation over 2 years had a focal VT mechanism elucidated (mean age 66±13 years; ejection fraction 46±14%; nonischemic cardiomyopathy 10). Repetitive failure of termination with antitachycardia pacing (ATP) (69% of patients) or defibrillator shocks (56%) was a common feature of focal VTs. A median of 3 VTs per patient were inducible (28 focal VTs, 34 re-entrant VTs; 53% of patients had both focal and re-entrant VT mechanism). Focal VTs more commonly originated from the right ventricle (RV) than the left ventricle (LV) (67% vs. 33%, respectively). In the RV, the RV outflow tract was the most common site (33% of all focal VTs), followed by the RV moderator band (22%), apical septal RV (6%), and lateral tricuspid annulus (6%). The lateral LV (non-Purkinje) was the most common LV focal VT site (16%), followed by the papillary muscles (17%). After median follow-up of 289 days, 78% of patients remained arrhythmia-free; no patients had recurrence of focal VT at repeat procedure. In patients with recurrence, defibrillator therapies were significantly reduced from a median of 53 ATP episodes pre-ablation to 10 ATP episodes post-ablation. During follow-up, 2 patients (11%) underwent repeat VT ablation; none had recurrence of focal VT. Focal VTs are common in patients with SHD and often coexist with re-entrant forms of VT. High failure rate of defibrillator therapies was a common feature of focal VT mechanisms. Uncovering and abolishing focal VT may further improve outcomes of catheter ablation in SHD.

Ventricular Tachycardia in Structural Heart Disease.

Patients with structural heart disease (SHD) are at risk of ventricular tachycardia (VT), which can be difficult to manage clinically. Many treatment options are currently available, but no single approach can be applied with 100% perfect results; often, a combination of therapies is required to achieve good control of ventricular arrhythmias. Coronary artery disease with previous myocardial infarction (MI) is the most common form of SHD presenting with VT, with scar-mediated reentry being the predominant mechanism. Other cardiomyopathies such as arrhythmogenic right ventricular cardiomyopathy, sarcoidosis, Chagas disease, and repaired congenital heart disease can also present in conjunction with ventricular arrhythmias. A thorough analysis of the patient’s history, 12-lead electrocardiogram, and imaging findings are essential for understanding the mechanism and guiding localization of the site of origin of the arrhythmia and the presence of underlying heart disease, which will improve outcomes following catheter ablation if such is indicated. Separately, antiarrhythmic drugs have not been shown to decrease mortality in this patient population but can help to reduce the VT burden and subsequently the need for implantable cardioverter-defibrillator therapy. Unfortunately, most antiarrhythmic agents are negative inotropes, with the possibility of worsening heart failure. This review aims to discuss the current options available for the management of VT in SHD.

Sex Differences in Cardiac Arrhythmias: Clinical and Research Implications.

Sex differences have the potential to impact diagnostic and therapeutic interventions in a wide variety of medical conditions, and cardiac arrhythmias are no exception.1 Studies evaluating pathophysiology, disease course, and therapeutic options for cardiac arrhythmias have been performed predominantly in male patients. However, catheter and device-based therapies coupled with landmark clinical trials have contributed to an improved understanding of this important aspect. The objective of this review is to present the current state of knowledge on sex differences in cardiac arrhythmias with a focus on clinical management, while highlighting gaps in knowledge that would benefit from future investigation. ### Atrial Fibrillation and Atrial Flutter #### Disease Burden Atrial fibrillation (AF) and atrial flutter (AFL) are the most commonly encountered tachyarrhythmias in clinical practice, with significant implications for public health and healthcare costs. Stroke, hospitalization, and loss of productivity are the major consequences of AF.2 The incidence of AF (per 1000 person-years) is reported to be between 1.6 and 2.7 in women and between 3.8 and 4.7 in men.2 The age-adjusted incidence and prevalence of AF is lower in women compared with that in men, and accordingly, the lifetime risk of AF from the Framingham Heart Study at 40 years of age was higher in men (26.0% for men versus 23.0% for women).3 Another analysis from the Framingham Heart Study demonstrated no significant sex differences in the risk of developing AFL.4 The prevalence of AF continues to rise among both men and women. In a study investigating the global burden of disease from 1980 to 2010, there was not only an increase in overall burden, incidence, and prevalence of AF, but most importantly an increase in AF-associated mortality in both men and women (Figure 1).5 The age-adjusted mortality for women was consistently higher compared with that for men from 1990 to 2010 (Figure …

Non-sustained microvolt level T-wave alternans in congenital long QT syndrome types 1 and 2

BackgroundPatients with long QT syndrome (LQTS) are predisposed to polymorphic ventricular tachycardia (VT) during adrenergic stimulation. Microvolt T-wave alternans (MTWA) is linked to vulnerability to VT in structural heart disease. The prevalence of non-sustained MTWA (NS-MTWA) in LQTS is unknown. Methods31 LQT1, 42 LQT2, and 80 controls underwent MTWA testing during exercise. MTWA tests were classified per standardized criteria, and re-analyzed according to the modified criteria to account for NS-MTWA. ResultsLQT1 and LQT2 patients had a significantly higher frequency of late NS-MTWA (26% and 12%) compared to controls (0%). There was no significant difference between the groups with respect to sustained and early NS-MTWA. Late NS-MTWA was significantly associated with QTc. ConclusionLQT1 and LQT2 patients had a higher prevalence of late NS-MTWA during exercise than matched controls. NS-MTWA likely reflects transient adrenergically mediated dispersion of repolarization, and could be a marker of arrhythmic risk in LQTS.

Entrainment Mapping.

Mapping during ventricular tachycardia (VT) aims to elucidate mechanism, describe myocardial propagation, and identify the origin and critical regions of VT that can be targeted for ablation, most commonly with radiofrequency ablation. Most VTs in structural heart disease are due to macro-reentry in and around scar. A combination of mapping techniques, including mapping to identify the arrhythmia substrate, activation sequence mapping, pace-mapping, and entrainment mapping, may be used to identify putative ablation targets. This review describes the principles of entrainment mapping as it pertains to catheter ablation of scar-related VT.

Necessity of epicardial ablation for ventricular tachycardia after sequential endocardial approach

BackgroundCatheter ablation (CA) of ventricular tachycardia (VT) is an important treatment option in patients with structural heart disease (SHD) and implantable cardioverter defibrillator (ICD). A subset of patients requires epicardial CA for VT. ObjectiveThe purpose of the study was to assess the significance of epicardial CA in these patients after a systematic sequential endocardial approach. MethodsBetween January 2009 and October 2012 CA for VT was analyzed. A sequential CA approach guided by earliest ventricular activation, pacemap, entrainment and stimulus to QRS-interval analysis was used. Acute CA success was assessed by programmed ventricular stimulation. ICD interrogation and 24h-Holter ECG were used to evaluate long-term success. ResultsOne hundred sixty VT ablation procedures in 126 consecutive patients (114 men; age 65±12years) were performed. Endocardial CA succeeded in 250 (94%) out of 265 treated VT. For 15 (6%) VT an additional epicardial CA was performed and succeeded in 9 of these 15 VT. Long-term FU (25±18.2month) showed freedom of VT in 104 pts (82%) after 1.2±0.5 procedures, 11 (9%) suffered from repeated ICD shocks and 11 (9%) died due to worsening of heart failure. ConclusionsDespite a heterogenic substrate for VT in SHD, endocardial CA alone results in high acute success rates. In this study additional epicardial CA following a sequential endocardial mapping and CA approach was performed in 6% of VT.Thus, due to possible complications epicardial CA should only be considered if endocardial CA fails.

Safety and efficacy of three-dimensional mapping systems in idiopathic ventricular tachycardia ablation

Background: Idiopathic ventricular tachycardia (VT) accounts for approximately 10% of all patients referred for evaluation of VT. 3-D mapping system has proved very useful in ablation of complex arrhythmias e.g. atrial fibrillation and VT in structural heart disease. The aim of the current study is to evaluate safety and efficacy of new 3-D mapping system in idiopathic VT ablation and comparison of between contact (Carto™) and noncontact (EnSite Array™ Catheter) mapping systems. Materials and Methods: Study population included 62 patients with idiopathic VT. (27 female 35 male, mean age 43.5 ± 22.4 years). Six patients had previously undergone unsuccessful ablation in other centers using conventional method. Site of VT/PVCs origin was RVOT in 44 (70.9%), LVOT in 4 (6.5%) and LV cavity 14 (22.6%) patients. VT was successfully ablated in 54/62 (87.1%) patients and ablation was not successful in 8/62 (12.9%) patients. VT was successfully ablated in all (6/6) patients who had previous failed ablation with conventional methods. Four (6.4%) patients developed procedure related complications. No patient with successful ablation had recurrence at six months follow up and 6/8 patients in whom ablation failed had recurrence during follow up. There was no difference in safety and efficacy of two mapping systems (success rate was 90.9% in EnSite and 82.5% in Carto (p 0.6)). Conclusion: New 3-D mapping systems (Carto™, EnSite Array™ Catheter) are very useful in ablation of idiopathic VTs with good acute success and short-term follow up. These systems are particularly useful in patients with failed ablation by conventional methods. There is no difference the two systems with regards to acute success, recurrence and complications rate.

Current Status and Future Directions of Ventricular Arrhythmia Ablation

Ventricular tachycardia (VT) catheter ablation has evolved over the past decade, allowing effective treatment of haemodynamically unstable and epicardial VTs in patients with structural heart disease previously not amenable to ablation. Catheter ablation reduces VT recurrences and thereby implantable cardioverter–defibrillator (ICD) shocks in 67–75% of patients, with a low incidence of procedure-related complications when performed in highly experienced centres. It can be life-saving in patients with electrical storm. Early use of ablation can be considered in selected patients who receive an ICD as an alternative to drug therapy provided that the procedure can be performed safely. Although acute results are promising, outcomes over the long-term are less favourable. An improved understanding of the VT substrate is mandatory for further advancement of a substrate-based ablation approach. Pre-procedural and intra-procedural imaging are likely to contribute to this. Whether catheter ablation will become first-line treatment for VT in structural heart disease and ultimately allow ICD implantation to be avoided in selected patients needs further evaluation.