Saagar Mahida

Liverpool Heart And Chest Hospital · Department of Cardiology

Background: Ventricular scar is traditionally highlighted on a bipolar voltage (BiVolt) map in areas of myocardium <0.50mV. We describe an alternative approach using Ripple Mapping (RM) superimposed onto a BiVolt map to differentiate post-infarct scar from conducting borderzone (BZ) during VT ablation. Methods: 15 consecutive patients (LVEF 30±7...

Objective We aimed to compare cryoballoon pulmonary vein isolation (PVI) with standard radiofrequency cavotricuspid isthmus (CTI) ablation as first-line treatment for typical atrial flutter (AFL). Methods Cryoballoon Pulmonary Vein Isolation as First-Line Treatment for Typical Atrial Flutter was an international, multicentre, open with blinded ass...

Aims Assess prevalence, risk factors, and management of patients with intra-cardiac thrombus referred for scar-related ventricular tachycardia (VT) ablation. Methods and results Consecutive VT ablation referrals between January 2015 and December 2019 were reviewed (n = 618). Patients referred for de novo, scar-related VT ablation who underwent pre...

Background Ultrasound (US) is being increasingly used to guide vascular access for electrophysiology (EP) procedures in many centres. Nonetheless, the incidence and predictors of vascular complications in the US era are limited. In this study, we describe our experience of vascular access-related complications associated with EP procedures which we...

The healthcare sector accounts for nearly 5% of global greenhouse gas emissions (GHG) and is a significant contributor to complex waste. Reducing the environmental impact of technology-heavy medical fields such as cardiac electrophysiology (EP) is a priority. The aim of this survey was to investigate the practice and expectations in European centre...

Introduction Flecainide has an established role in the treatment of common arrhythmias. The primary mechanism of action is blockade of the cardiac sodium channel, which manifests on the surface electrocardiogram (ECG) as prolongation of the PR interval and an increase in the QRS duration. The European Society of Cardiology recommends an ECG is perf...

Objective Atrial fibrillation (AF) ablation services were significantly affected by the COVID-19 pandemic. We aimed to evaluate a symptom-based clinician prioritisation scheme for waiting list management compared with patient-completed quality of life (QoL) scores. We also sought to understand factors influencing QoL, particularly the impact of COV...

Purpose There is a relative paucity of data on antemortem clinical characteristics of young (age 1 to 35 years) sudden death (SD) victims. The aim of the study was to characterize antemortem characteristics of SD victims, in a selected national cohort identified by a web search. Methods A dataset of all SD (January 2010 and December 2015) was buil...

Background Catheter ablation of ventricular tachycardia (VT) is associated with potential major complications, including mortality. The risk of acute complications in patients with ischaemic cardiomyopathy (ICM) and non-ischaemic cardiomyopathy (NICM) has not been systematically evaluated. Methods PubMed was searched for studies of catheter ablati...

The optimal ablation strategy for persistent atrial fibrillation (PsAF) remains to be defined. We sought to compare very long-term outcomes between linear ablation and electrogram (EGM)-guided ablation for PsAF. In a retrospective analysis, long-term arrhythmia-free survival compared between two propensity-score matched cohorts, one with pulmonary...

Background Accurate mapping of the compact AV node is critical during ablation of a range of arrhythmias. Objective We hypothesize that micro-electrode (ME) embedded catheters more accurately define the near-field compact AV node as compared to conventional catheters. Methods Mapping phase: Detailed AV junction maps were created in 47 patients us...

The optimal ablation strategy for persistent atrial fibrillation (PsAF) remains to be defined. We sought to compare very long-term outcomes between linear ablation and electrogram (EGM)-guided ablation for PsAF. In a retrospective analysis, long-term arrhythmia-free survival compared between two propensity-score matched cohorts, one with pulmonary...

Funding Acknowledgements Type of funding sources: None. Introduction Catheter ablation for atrial fibrillation (AF) is largely offered for symptomatic relief. The ORBIT registry has shown that patients with a higher EHRA class and lower quality of life (QoL) scores (AFEQT score <65.7) are more likely to suffer emergency hospital admissions. To hel...

Background: The optimal ablation strategy for persistent atrial fibrillation (PsAF) remains to be defined. We sought to compare very long-term outcomes between linear ablation and electrogram (EGM)-guided ablation for PsAF. Methods: In a retrospective analysis, long-term arrhythmia-free survival compared between two propensity-score matched cohorts...

PurposeTreatment of typical atrial flutter (AFL) with cavo-tricuspid isthmus (CTI) ablation is associated with a high occurrence rate of new onset atrial fibrillation (AF) during follow-up. There are data to support the addition of pulmonary vein isolation (PVI) to CTI ablation in patients with both AF and AFL, but the role of cryoballoon PVI only,...

Purpose: The aim of this study was to analyze the feasibility and reproducibility of using image integration software at a remote setting over the MUSIC network to perform image-guided VT ablation. Furthermore, we analyzed the efficacy of a focused workflow with electroanatomical mapping (EAM) limited to imaging-defined scar. Methods: In a prosp...

Background Beyond pulmonary vein isolation (PVI), the optimal ablation strategy for persistent atrial fibrillation (AF) remains poorly defined. Objectives We sought to examine a novel comprehensive ablation strategy (Marshall-PLAN) strictly based on anatomical considerations. Methods Left atrial (LA) sites were sequentially targeted as follows: (...

The identification of a pathogenic SCN5A variant confers an increased risk of conduction defects and ventricular arrhythmias (VA) in Brugada syndrome (BrS). However, specific aspects of sodium channel function that influence clinical phenotype have not been defined. A systematic literature search identified SCN5A variants associated with BrS. Sodiu...

Background Risk of heart block during radiofrequency ablation of AVNRT and septal accessory pathways is minimized by rapidly ceasing ablation in response to markers of risk, such as atrio-ventricular dissociation, fast junctional rhythm, PR interval prolongation, or two consecutive atrial or ventricular depolarisations. Currently this is done manua...

We present a case of a 67‐year‐old female with a previous history of a pulmonary vein isolation for paroxysmal atrial fibrillation who presented with supraventricular bigeminy with a constant coupling interval. The supraventricular bigeminy originated from the anterior mitral annulus with initial mapping suggestive of a focal mechanism. However det...

Objectives This study systematically evaluated mechanisms of atrial tachycardia (AT) by using ultra-high-resolution mapping in a large cohort of patients. Background An incomplete understanding of the mechanism of AT is a major determinant of ablation failure. Methods Consecutive patients with ≥1 AT (excluding cavotricuspid isthmus–dependent flut...

Background Individuals with Brugada syndrome (BrS) in whom a variant can be found in SCN5A, the gene encoding the alpha subunit of the cardiac sodium channel, have a more marked phenotype. However, many SCN5A variants have little apparent effect on the sodium current INa. We asked whether in vitro functional assessment of SCN5A variants could refi...

The retrograde aortic route is a widely used access route for mapping and ablation of ventricular tachycardias (VT) arising from the left ventricular endocardium. With the expanding role of VT ablation in patients with significant co‐morbidity, the choice between the retrograde aortic and transseptal access routes is an increasingly important consi...

Background: AF ablation is a complex procedure, generally requiring at least one overnight hospital stay. We investigated the safety and feasibility of early mobilization and same-day discharge following streamlined peri-ablation management for atrial fibrillation (AF). Methods: From 2014 we offered same-day discharge to selected patients who un...

Background: The presence of heart failure (HF) has been associated with poorer outcomes in patients undergoing catheter ablation (CA) for atrial fibrillation (AF). However the effectiveness of CA amongst the subset of patients with tachycardia-induced cardiomyopathy (TIC) remains poorly defined. Methods and results: In a retrospective analysis w...

Background-—The natural history and long-term outcome in pediatric patients with idiopathic ventricular fibrillation (IVF) are poorly characterized. We sought to define the clinical characteristics and long-term outcomes of a pediatric cohort with an initial diagnosis of IVF. Methods and Results-—Patients were included from an International Registr...

Table S1. Characteristics of Patients With RyR2 and Triadic Mutations Table S2. Clinical Characteristics of Genotype‐Positive Patients

Aims: Video-assisted thoracoscopic surgery (VATS) ablation has been advocated as a treatment option for non-paroxysmal atrial fibrillation (AF) in recent guidelines. Real-life data on its safety and efficacy during a centre’s early experience are sparse. Methods and results: Thirty patients (28 persistent/longstanding persistent AF) underwent stand...

Introduction: Point-by-point standard ablation using single-tip (conventional) catheter is the main current technique for pulmonary vein isolation (PVI) but it can be challenging. A circular, multi-electrode, mapping and ablation catheter (nMARQ) may provide faster PVI. Methods: We designed a randomized comparison between circular versus convention...

Background: The comparative efficacy of antiarrhythmic drug (AAD) therapy vs ventricular tachycardia (VT) ablation in arrhythmogenic right ventricular cardiomyopathy (ARVC) is unknown. Objective: We compared outcomes of AAD and/or β-blocker (BB) therapy with those of VT ablation (with AAD/BB) in patients with ARVC who had recurrent VT. Methods:...

Introduction Demonstration of exit block after pulmonary vein isolation (PVI) is the cornerstone of ablation for atrial fibrillation (AF). It requires the demonstration of local PV capture and absence of conduction to the atrium but is often challenging due to the inability to see local paced PV evoked potentials. We retrospectively examine the abi...

Background A large number of SCN5A variants have been reported to underlie Brugada syndrome (BrS). However, the evidence supporting individual variants is highly heterogeneous. Objective We systematically re‐evaluated all SCN5A variants reported in BrS using the 2015 ACMG‐AMP guidelines Methods A Pubmed/Embase search was performed to identify all...

Background Catheter ablation for atrial fibrillation (AF) has traditionally involved at least an overnight stay in hospital. We hypothesised that systematic use of ultrasound-guided venous access and implementation of streamlined peri-ablation anticoagulation policy would allow early mobilisation for patients and facilitate same-day discharge. Met...

Background Implantable cardiac defibrillators (ICD) improve survival from life-threatening arrhythmias, and have rapidly become a standard therapy for those at risk of arrhythmic cardiac death. However, shock therapy can be associated with anxiety and a reduction in quality of life. We sought to ascertain anxiety levels in our patient cohort with I...

Introduction The safety and efficacy of Standalone video assisted thoracoscopic surgical (VATS) ablation for atrial fibrillation (AF) has not been established. In particular, comparative data with catheter ablation (CA) are scarce. Methods We prospectively collected data on 30 consecutive VATS AF ablations (mean age 58±10 years, 26 male) performed...

Ventricular tachycardia (VT) is a major cause of sudden cardiac death. The majority of malignant VTs occur in patients with structural heart disease. Multimodality imaging techniques play an integral role in determining the underlying etiology and prognostic significance of VT. In recent years, advances in imaging technology have enabled characteri...

Introduction: It is largely believed that atrial tachycardias (ATs) encountered during ablation of persistent atrial fibrillation (PsAF) are a byproduct of ablative lesions. We aimed to explore the alternative hypothesis that they may be priori drivers of AF remaining masked until other AF sources are reduced or eliminated. Methods and results:...

Background: Right ventricular (RV)-scar related ventricular tachycardia (VT) is often due to arrhythmogenic right ventricular cardiomyopathy/dysplasia (ARVC/D) or cardiac sarcoidosis (CS), but some patients whose clinical course has not been described do not fulfill diagnostic criteria for these diseases. We sought to characterize the electrophysi...

Introduction: Lack of transmural lesion formation during radiofrequency (RF) ablation for ventricular tachycardia (VT) is an important determinant of arrhythmia recurrence. The aim of this proof-of-concept study was to evaluate safety and efficacy of a new and more powerful cryoablation system for ventricular ablation. Methods and results: Five...

BACKGROUND: In contrast to patients with left bundle branch block (LBBB), heart failure patients with narrow QRS and nonspecific intraventricular conduction delay (NICD) display a relatively limited response to cardiac resynchronization therapy. We sought to compare left ventricular (LV) activation patterns in heart failure patients with narrow QRS...

Background: In contrast to patients with left bundle branch block (LBBB), heart failure patients with narrow QRS and nonspecific intraventricular conduction delay (NICD) display a relatively limited response to cardiac resynchronization therapy. We sought to compare left ventricular (LV) activation patterns in heart failure patients with narrow QR...

Michowitz et al1 present an interesting study on the prevalence of familial atrioventricular nodal reentrant tachycardia (AVNRT). They report a prevalence of 127 out of 10 000 of familial AVNRT with a …

Background: The underlying mechanisms sustaining human persistent atrial fibrillation (PsAF) is poorly understood. Objectives: This study sought to investigate the complexity and distribution of AF drivers in PsAF of varying durations. Methods: Of 135 consecutive patients with PsAF, 105 patients referred for de novo ablation of PsAF were prosp...

Younger age, positive family history and reverse curve morphology predict informative results from gene panel analysis for hypertrophic cardiomyopathy (HCM) Background HCM is a disease characterised by otherwise unexplained hypertrophy of the myocardium, often as a result of a gene mutation. Phenotypic expression is estimated at 1 in 500 and genet...

Background: The genetic basis of atrial fibrillation (AF) and congenital heart disease remains incompletely understood. Objective: We sought to determine the causative mutation in a family with AF, atrial septal and ventricular septal defects. Methods: We evaluated a pedigree with 16 family members, one with an atrial septal defect, one with a...

Introduction: Substrate-based ablation for scar-related ventricular tachycardia (VT) has gained prominence: however, there is limited data comparing it to ablation guided predominantly by activation and entrainment mapping of inducible and hemodynamically tolerated VTs. We compared the acute procedural efficacy and outcomes of predominantly substr...

Background: During the past years, many innovations have been introduced to facilitate catheter ablation of post-myocardial infarction ventricular tachycardia. However, the predictors of outcome after ablation were not thoroughly studied. Methods and results: From 2009 to 2013, consecutive patients referred for post-myocardial infarction ventric...

The early repolarization (ER) pattern on the 12-lead electrocardiogram is characterized by J point elevation in the inferior and/or lateral leads. The ER pattern is associated with an increased risk of ventricular arrhythmias and sudden cardiac death (SCD). Based on studies in animal models and genetic studies, it has been proposed that J point ele...

Objectives This study sought to characterize the clinical characteristics, atrial substrate, and prognosis in a subgroup of patients with persistent atrial fibrillation (AF) from the onset (PsAFonset). Background Patients with AF frequently progress from trigger-driven paroxysmal arrhythmias to substrate-dependent persistent arrhythmias. Methods...

Background: Although multi-detector computed tomography (MDCT) and cardiac magnetic resonance (CMR) can assess the structural substrate of ventricular tachycardia (VT) in ischemic cardiomyopathy (ICM), non-ICM (NICM) and arrhythmogenic right ventricular cardiomyopathy (ARVC), the usefulness of systematic image integration during VT ablation remain...

Aims: Atrial fibrillation (AF) is a common arrhythmia with an important heritable aspect. The genetic factors underlying AF have not been fully elucidated. Methods and results: We screened six candidate genes (CAV1, KCNJ2, KCNQ1, NKX2.5, PITX2, and TBX5) for novel mutations in 139 patients of Chinese descent with early-onset AF and 576 controls....

Noninvasive mapping allows unprecedented panoramic beat-to-beat mapping of atrial fibrillation (AF) and its underlying dynamic processes. This provides an individualized framework to guide catheter ablation of persistent AF. This chapter discusses the utility of noninvasive mapping in persistent AF ablation, including the methodology, the identific...

Background: -VT recurrence can occur after VT ablation due to incomplete and/or non-transmural ventricular lesion formation. We sought to compare the lesions made by a novel irrigated needle catheter to conventional radiofrequency (RF) lesions. Methods and results: -Thirteen female sheep (4.6±0.7yrs, 54±8kg) were studied. In 7 sheep, 60s RF appl...

Atrial fibrillation (AF) is the most common rhythm disorder, and is strongly associated with thromboembolic events and heart failure. Over the past decade, catheter ablation of AF has advanced considerably with progressive improvement in success rates. However, interventional treatment is still challenging, especially for persistent and long-standi...

http://www.ncbi.nlm.nih.gov/pubmed/26527625

Background: Inferolateral early repolarization (ER) is highly prevalent and is associated with idiopathic ventricular fibrillation (VF). Objective: To evaluate the potential role of T wave parameters to differentiate between malignant and benign ER. Methods: We compared the ECGs of patients with ER and VF (n=92) with control subjects with asym...

Background: -Radiofrequency ablation (RFA) from the epicardial space for ventricular arrhythmias (VAs) is limited or impossible in some cases. Reasons for epicardial ablation failure and the impact on outcome have not been systematically analyzed. Methods and results: -We assessed reasons for epicardial RFA failure relative to the anatomical tar...

Aim: To determine whether ventricular tachycardia (VT) recurrences in arrhythmogenic RV cardiomyopathy (ARVC) and nonischemic cardiomyopathy (NICM) are related to incomplete ablation or disease progression. Methods: ARVC and NICM patients with 2 substrate maps of the same diseased ventricle with an interprocedural delay of ≥12months were include...

-The correlates of left ventricular (LV) substrate in arrhythmogenic right ventricular cardiomyopathy (ARVC) are largely unknown. -Thirty-two ARVC patients (47±14years, 6 women) were included. RV and LV dysplasia were defined from MDCT and CMR imaging. Arrhythmias were characterized as right-sided or left-sided on 12-lead ECG recordings at baseline...

Substrate-based VT ablation is mostly based on maps acquired with ablation catheters. We hypothesized that multipolar mapping catheters are more effective for identification of scar and local abnormal ventricular activity (LAVA). Phase1: In a sheep infarction model (2 months post-infarction), substrate mapping and LAVA tagging (CARTO(®) 3) was perf...

http://www.ncbi.nlm.nih.gov/pubmed/25828599

http://www.ncbi.nlm.nih.gov/pubmed/25925229

Over the past few decades, significant progress has been made in understanding the mechanistic basis of atrial fibrillation (AF). One of the most important discoveries in this context has been that pulmonary veins (PV) play a prominent role in the pathogenesis of AF. PV isolation has since become the most widely used technique for treatment of paro...

-Ventricular tachycardia (VT) refractory to anti-arrhythmic drugs (AADs) and standard percutaneous catheter ablation techniques portends a poor prognosis. We characterized the reasons for ablation failure and describe alternative interventional procedures in this high-risk group. -67 patients with VT refractory to 4±2 AADs and 2±1 prior endocardial...

-Left ventricular assist devices (LVADs) are increasingly used as a bridge to cardiac transplantation or as destination therapy. Patients with LVADs are at high risk for ventricular arrhythmias (VA). This study describes VA characteristics and ablation in patients implanted with a Heart Mate 2 (HM2) device. -All patients with a HM2 device who under...

nMARQ is a multipolar catheter designed to simultaneously ablate at multiple sites around the pulmonary vein (PV) circumference with a single radiofrequency application. We sought to define the safety and efficacy of atrial fibrillation (AF) ablation with the nMARQ catheter. In a multicenter study, patients with drug-refractory AF were included. Pr...

to flex over the course of insertion, and tactile assessment of force and perception of cardiac motion was limited. In this report, we describe our initial experience with the “needle-inneedle” (NIN) technique of epicardial access in which a short 18G needle is inserted under the sternum and the long 21G needle is inserted through the 18G needle. I...

-Epicardial ventricular tachycardia (VT) ablation is associated with risks of coronary artery (CA) and phrenic nerve (PN) injury. We investigated the role of multidetector CT (MDCT) in visualizing CA and PN during VT ablation. -Ninety-five consecutive patients (86 males, age 57±15) with VT underwent cardiac MDCT. The PN detection rate and anatomica...