Pulsed Field Ablation of Atrial Fibrillation: An Initial Australian Single-Centre Experience.

BACKGROUND: Pulsed field ablation (PFA) is a newer ablation energy source with the potential to reduce complications and improve efficacy compared to conventional thermal atrial fibrillation (AF) ablation. This study aimed to present an initial single-centre Australian experience of PFA for AF ablation. METHODS: Initial consecutive patients undergoing PFA for paroxysmal or persistent AF at a single centre were included. Baseline patient characteristics, procedural data and clinical outcomes were collected prospectively at the time of the procedure. Patients were followed up at 3 months and 6-monthly thereafter. RESULTS: In total, 100 PFA procedures were performed in 97 patients under general anaesthesia. All pulmonary veins (403 of 403) were successfully isolated acutely. Median follow-up was 218 days (range, 16-343 days), and the Kaplan-Meier estimate for freedom from atrial arrhythmias at 180 days was 87% (95% confidence interval 79%-95%). Median procedure time was 74 minutes (range, 48-134 minutes). Median fluoroscopy dose-area product was 345 µGym2 (interquartile range, 169-685 µGym2). Two (2%) pseudoaneurysm vascular access complications occurred. There were no cases of thromboembolic complications, stroke, phrenic nerve palsy, pulmonary vein stenosis, atrio-oesophageal fistula, or pericardial tamponade. CONCLUSIONS: Pulsed field ablation can be performed safely and efficiently, with encouraging efficacy in early follow-up. Further data and clinical trials will be required to assess the comparative utility of PFA in contemporary AF ablation practice.

Consecutive Experience with Left Bundle Branch Area Pacing in a High-Volume Australian Centre.

INTRODUCTION: Left-bundle branch area pacing (LBBAP) is a relatively new technique for conduction system pacing. Australian safety and efficacy data is currently lacking. We aim to evaluate the learning curve, medium-term safety, and lead performance in a high-volume Australian setting. METHODS: We performed a retrospective cohort study of 200 consecutive LBBAP procedures performed by a single operator at two centres between January 2019 and May 2020. Left bundle branch area pacing was performed predominantly via left subclavian access using a 69 cm Medtronic SelectSecure 3830 pacing lead and a preformed non-steerable C315-His sheath. Procedural success was defined as evidence of left septal or left bundle branch area capture as evidenced by a right bundle branch block-like paced morphology. Procedural characteristics, and follow-up (including lead performance) data were collected. Procedural efficiency over time, as well as safety data, were collected. RESULTS: Median age was 78.26 years (interquartile range [IQR] 71-85), 37% were female. Atrial fibrillation was present in 22%. The left ventricular ejection fraction <50% in 24%, atrioventricular (AV) block was present in 43.5%, left bundle branch block in 22.5% and right bundle branch block in 24.5%. Acute procedural success was 91.5%. Implant threshold was 0.6V @ 0.5 ms, and 0.75V @ 0.5 ms at 11.9 months of follow-up. The QRS was significant reduced (baseline 134 ms vs implant 114 ms, p<0.001) There was a reduction in procedural time and X-ray dose over the course of the study. There were no complications specific to LBBAP. CONCLUSION: LBBAP appears to be a safe and effective pacing strategy. The QRS duration was significantly reduced compared to baseline. There appears to be an early learning curve with LBBAP.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias: executive summary.

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

The Electrocardiographic Footprints of Ventricular Ectopy.

Ventricular ectopics, also known as ventricular extrasystoles, premature ventricular contractions or complexes (PVC) and ventricular premature depolarisations (VPD) are beats arising from within the ventricles. When they occur in groupings such as bigeminy, trigeminy, couplets and triplets they are referred to as ventricular ectopy. The electrocardiographic (ECG) footprints of a ventricular ectopic include a broad (>110 ms), premature, ventricular complex (QRS deflection); no evidence of pure atrioventricular (AV) conduction; a full, more than, or less than compensatory pause; and discordant QRS and T wave axis. Ventricular ectopy is a very common finding on Holter monitoring at all ages, but particularly in the elderly. In the otherwise normal heart, ventricular ectopy is generally infrequent and a benign finding, but in patients with heart disease, they may be a harbinger to more serious ventricular tachyarrhythmias. In this review, the range and manifestations of ventricular ectopy will be explored in detail with ECG examples.

Late Potentials and Early Repolarisation Are Associated With Serious Mental Illness and May Portend Increased Arrhythmic Risk.

BACKGROUND: Patients with serious mental illness (SMI) have an increased risk of sudden death. Higher rates of signal-averaged electrocardiogram (SAECG) abnormal late potentials (LP), which may be a predictor of sudden death risk, have been shown in patients with schizophrenia. We aimed to assess the prevalence and predictors of electrocardiograph (ECG) and SAECG abnormalities in a mixed SMI population. METHODS: Consecutive consenting inpatients with SMI had 12-lead ECG and SAECG recorded in addition to demographics, diagnoses and medications. Standard criteria for abnormal SAECG were applied. Multivariate regression analysis was performed to determine predictors of SAECG abnormalities including diagnoses, body mass index, ECG parameters, psychotropic medication use, and medications associated with Long QT or Brugada syndromes. RESULTS: Eighty (80) patients, 49% male, mean age 39±17 years were included. SAECG criteria abnormality for 1, 2 or 3 criteria were seen in 19, 3 and 5 cases (34% in total) respectively. Early repolarisation pattern was seen in 19% of patients. SAECG abnormality was associated with male gender (OR 7.3; 95% CI 2.3-23.4), and schizophrenia/schizoaffective disorder diagnosis (OR 7.4; 95% CI 1.9-29.0), but not with medication type or dose. CONCLUSIONS: In the mixed SMI population studied, there was a high rate of SAECG-detected late potentials (34%) and early repolarisation pattern (19%). Schizophrenia/schizoaffective disorder diagnosis was the strongest multivariate predictor identified. Further studies are needed to define the mechanism and significance of these cardiac abnormalities in SMI patients.

2019 HRS/EHRA/APHRS/LAHRS expert consensus statement on catheter ablation of ventricular arrhythmias.

Ventricular arrhythmias are an important cause of morbidity and mortality and come in a variety of forms, from single premature ventricular complexes to sustained ventricular tachycardia and fibrillation. Rapid developments have taken place over the past decade in our understanding of these arrhythmias and in our ability to diagnose and treat them. The field of catheter ablation has progressed with the development of new methods and tools, and with the publication of large clinical trials. Therefore, global cardiac electrophysiology professional societies undertook to outline recommendations and best practices for these procedures in a document that will update and replace the 2009 EHRA/HRS Expert Consensus on Catheter Ablation of Ventricular Arrhythmias. An expert writing group, after reviewing and discussing the literature, including a systematic review and meta-analysis published in conjunction with this document, and drawing on their own experience, drafted and voted on recommendations and summarized current knowledge and practice in the field. Each recommendation is presented in knowledge byte format and is accompanied by supportive text and references. Further sections provide a practical synopsis of the various techniques and of the specific ventricular arrhythmia sites and substrates encountered in the electrophysiology lab. The purpose of this document is to help electrophysiologists around the world to appropriately select patients for catheter ablation, to perform procedures in a safe and efficacious manner, and to provide follow-up and adjunctive care in order to obtain the best possible outcomes for patients with ventricular arrhythmias.

Ventricular Ectopy in the Context of Left Ventricular Systolic Dysfunction: Risk Factors and Outcomes Following Catheter Ablation.

BACKGROUND: Ectopy-mediated cardiomyopathy (EMC) is a potentially reversible form of left ventricular systolic dysfunction. Various risk factors for the development of EMC have been proposed in the literature. We aim to assess medium term outcomes of focal ventricular arrhythmia (VA) ablation in the setting of cardiomyopathy (CMP) and to validate published risk factors for EMC. METHODS: Medium term recovery of left ventricular (LV) function and freedom from VA recurrence was assessed and compared between patients undergoing focal VA ablation in the setting of CMP and a control group with normal LV function. Univariate and multivariate analyses for CMP risk factors were performed and compared against prior published risk factors. RESULTS: Of 152 patients who underwent 170 focal VA ablation procedures, 54 (36%) had CMP and the remaining 98 patients had normal LV systolic function. At medium term follow-up, 85% of patients with CMP were free of VA recurrence and median left ventricular ejection fraction (LVEF) had improved from 40 to 52%. Age, male gender, premature ventricular complex (PVC) burden, non- right ventricular outflow tract (RVOT) sites of origin, PVC QRS duration and PVC minimum coupling interval were predictive of CMP on univariate analysis, but only gender persisted on multivariate analysis. CONCLUSIONS: Medium term outcome in patients undergoing focal VA in the setting of CMP are satisfactory with improvement in LV function achievable in most patients. Prior risk factors described in the literature are variable and inconsistent, likely reflecting heterogeneous study populations.

The Footprints of Electrocardiographic Interference: Fact or Artefact.

Corporeal and particularly extra-corporeal interference is a very common problem encountered with both resting electrocardiograph (ECG) tracings and ambulatory recordings. The interference may be either electrical or mechanical and if severe, may affect the interpretation of the tracings. The interference, seen as artefact, can be divided into obvious, subtle or complicated. Obvious artefact may result from poor electrode attachment or body motion, whereas electrical interference is predominantly 50 or 60 Hz alternating current or radiofrequency waves from power lines, electrical equipment, mobile phones, fluorescent lights and electrical diathermy. Careful attention to the application of electrodes and finding the best environment for performing a 12-lead ECG will eradicate most interference. When subtle, the artefact can mimic cardiac arrhythmias, leading to incorrect interpretation of the tracings. There is also a complicated interference group, usually due to implanted cardiac electronic pacing devices and neurostimulators. These create persistent artefact, which may result in repeated unsuccessful attempts at procuring an artefact free tracing. This manuscript will describe the genesis of interference, how an ECG machine or monitor deals with interference and will discuss the common causes of interference. The characteristic patterns will be described and clues provided on how to differentiate subtle artefact from cardiac arrhythmias.

The Electrocardiographic Footprints of Atrial Ectopy.

Atrial ectopics, also known as a premature atrial complexes (PAC) or atrial premature depolarisations (APD), are supraventricular beats arising from a focus other than the sinus node. Because the various foci provide an array of electrocardiographic (ECG) appearances, an extensive, but confusing nomenclature has developed. Atrial ectopics are a very common finding on Holter ECG monitoring at all ages, the incidence increasing in frequency with age. In the otherwise normal heart, they are generally infrequent and an innocent finding, but in patients with heart disease, they may be a harbinger to more serious atrial tachyarrhythmias. In this review, the ECG footprints of atrial ectopy will be defined. These footprints include prematurity and P wave morphology. The associated features of variable atrioventricular (AV) conduction, variable post-ectopic pauses and variable QRS morphology due to aberrancy will also be discussed. Each of these features will be explained in detail with ECG examples.

The Surface Electrocardiograph in Ventricular Arrhythmias: Lessons in Localisation.

The 12-lead electrocardiograph (ECG) is of critical importance both in the diagnosis of wide complex tachycardia and in the further classification, characterisation and management of ventricular arrhythmias. With its diligent application and interpretation, remarkable precision can be achieved in the localisation of the site of origin of ventricular arrhythmias and this may have major implications in the care of these patients. This review discusses the technical, anatomic and mechanistic basis of ECG interpretation in ventricular arrhythmias.

Frequent Ventricular Ectopy: Implications and Outcomes.

Frequent ventricular ectopy is a common clinical presentation in patients suffering idiopathic ventricular outflow tract arrhythmias. These are focal arrhythmias that generally occur in patients without structural heart disease and share a predilection for characteristic anatomic sites of origin. Mechanistically, they are generally due to cyclic adenosine monophosphate (cAMP)-mediated triggered activity. As a result, there is typically an exercise or catecholamine related mode of induction and often a sensitivity to suppression with adenosine. Treatment options include clinical surveillance, medical therapy with anti-arrhythmic agents or catheter ablation. Medical therapy may offer symptomatic benefit but may have side-effects and usually results in burden reduction rather than eradication of ectopy. Catheter ablation using contemporary mapping techniques, whilst associated with some inherent procedural risk, is a potentially curative and safe option in most patients. Although usually associated with a good prognosis, some patients may develop an ectopy-mediated cardiomyopathy or, rarely, ectopy-induced polymorphic ventricular arrhythmias; catheter ablation is the treatment of choice in those patients.

Leadless Permanent Pacing: A Single Centre Australian Experience.

BACKGROUND: To describe the performance and clinical outcomes of consecutive patients having a leadless pacemaker (LP) implanted at a single institution. METHODS: Clinical data and device parameters were prospectively collected on all patients undergoing LP implantation from November 2015 to April 2018. RESULTS: A total of 79 patients (52 male), median age of 78 years, was included. Leadless pacemaker implantation was successful in 76 patients (96%). Implantation failed in two patients due to excessive venous tortuosity and due to inadequate sensing in another. Seventy-three (73) patients (96%) had chronic atrial fibrillation and all had a Class I or II indication for pacing. Procedure time was 29minutes (IQR 21-43) and fluoroscopy time was 8minutes (IQR 5-13). The median R wave at implant was 11.2mV (IQR 6.9-15.0). The median capture threshold at 0.24ms was 0.5V (IQR 0.4-0.9) and impedance was 754Ω (IQR 680-880). Intraprocedural acute dislodgement occurred in one patient following cutting of the tether but successful snaring and reimplantation was performed. During a median follow-up of 355days (range 9-905), overall electrical performance has been excellent. No patients have been readmitted for device revision or complications. Five (5) patients (7%) died during follow-up from unrelated causes. CONCLUSIONS: Leadless pacemakers can be implanted safely and effectively in the majority of patients. Device electrical performance was excellent over a median follow-up of 12 months.

Arrhythmogenic Cardiomyopathy in 2018-2019: ARVC/ALVC or Both?

Arrhythmogenic cardiomyopathy (ACM) is now commonly used to describe any form of non-hypertrophic, progressive cardiomyopathy characterised by fibrofatty infiltration of the ventricular myocardium. Right ventricular (RV) involvement refers to the classical arrhythmogenic right ventricular cardiomyopathy, but left ventricular, or bi-ventricular involvement are now recognised. ACM is mostly hereditary and associated with mutations in genes encoding proteins of the intercalated disc. ACM classically manifests as ventricular arrhythmias, and sudden death may be the first presentation of the disease. Heart failure is seen with advanced stages of the disease. Diagnosis can be challenging due to variable expressivity and incomplete penetrance, and is guided by established Taskforce criteria that incorporate electrical features (12-lead electrocardiography (ECG), features of ventricular arrhythmias), structural features (on imaging via echo and cardiac magnetic resonance imaging [MRI]), tissue characteristics (via biopsy), and familial/genetic evaluation. Electrical abnormalities may precede structural alterations, which also make diagnosis challenging, especially in differentiating ACM from other conditions such as benign right ventricular arrhythmias, channelopathies such as Brugada, or the Athlete's Heart. Genetic testing is critical in identifying familial mutations and initiating cascade testing, but finds a pathogenic mutation in only ∼50% of patients. Some critical genotype-phenotype correlations do exist and may help guide risk stratification and give clues to disease progression. Therapeutic strategies include restriction from high endurance and competitive sports, ß-blockers, antiarrhythmic drugs, heart failure medications, implantable cardioverter-defibrillators and combined endocardial/epicardial catheter ablation. Ablation has emerged as the treatment of choice for recurrent ventricular arrhythmias in ACM. This state-of-the-art review outlines the pathogenesis, diagnosis and treatment of ACM in the contemporary era.

National Heart Foundation of Australia and Cardiac Society of Australia and New Zealand: Australian clinical guidelines for the diagnosis and management of atrial fibrillation 2018.

INTRODUCTION: Atrial fibrillation (AF) is increasing in prevalence and is associated with significant morbidity and mortality. The optimal diagnostic and treatment strategies for AF are continually evolving and care for patients requires confidence in integrating these new developments into practice. These clinical practice guidelines will assist Australian practitioners in the diagnosis and management of adult patients with AF. Main recommendations: These guidelines provide advice on the standardised assessment and management of patients with atrial fibrillation regarding: screening, prevention and diagnostic work-up; acute and chronic arrhythmia management with antiarrhythmic therapy and percutaneous and surgical ablative therapies; stroke prevention and optimal use of anticoagulants; and integrated multidisciplinary care. Changes in management as a result of the guideline: Opportunistic screening in the clinic or community is recommended for patients over 65 years of age. The importance of deciding between a rate and rhythm control strategy at the time of diagnosis and periodically thereafter is highlighted. ß-Blockers or non-dihydropyridine calcium channel antagonists remain the first line choice for acute and chronic rate control. Cardioversion remains first line choice for acute rhythm control when clinically indicated. Flecainide is preferable to amiodarone for acute and chronic rhythm control. Failure of rate or rhythm control should prompt consideration of percutaneous or surgical ablation. The sexless CHA2DS2-VA score is recommended to assess stroke risk, which standardises thresholds across men and women; anticoagulation is not recommended for a score of 0, and is recommended for a score of ≥ 2. If anticoagulation is indicated, non-vitamin K oral anticoagulants are recommended in preference to warfarin. An integrated care approach should be adopted, delivered by multidisciplinary teams, including patient education and the use of eHealth tools and resources where available. Regular monitoring and feedback of risk factor control, treatment adherence and persistence should occur.

Catheter ablation of papillary muscle arrhythmias: Implications of mitral valve prolapse and systolic dysfunction.

BACKGROUND: The left ventricular (LV) papillary muscles are important components of the mitral valve apparatus. Catheter ablation of ventricular arrhythmias from these sites is challenging. We aim to describe the association between LV papillary muscle ventricular arrhythmias (VAs) and mitral valve prolapse (MVP), and to determine the outcomes of ablation in these patients with a focus on those with MVP and cardiomyopathy. METHODS: A total of 152 patients underwent 170 consecutive procedures for ablation of focal VAs. MVP and cardiomyopathy were diagnosed by echocardiography. Outcomes following ablation were assessed in three groups: (1) LV papillary muscle VAs versus other sites, (2) LV papillary muscle VAs by the presence of MVP, and (3) LV papillary muscle VAs in the setting of cardiomyopathy. RESULTS: Nine of 23 (39%) patients undergoing ablation of LV papillary muscle VAs had MVP compared to none of 129 (0%) patients at other sites (P < 0.001). In the former group, acute procedural success was achieved in 60% and 80% of those with and without MVP, respectively (P = 0.28). Medium-term outcomes were comparable (P = 0.75). In patients with cardiomyopathy, the median LV ejection fraction improved from 40% to 54% following ablation (P = 0.007). CONCLUSIONS: Although MVP is strongly associated with LV papillary muscle VAs, MVP does not adversely affect the acute or medium-term outcomes of ablation. Systolic function can improve following ablation in patients with ectopy-mediated cardiomyopathy due to papillary muscle VAs.

Epicardial Brugada syndrome ablation unmasking inferior J waves.

Patients with Brugada syndrome are at risk of life-threatening ventricular arrhythmias. Epicardial substrate ablation for Brugada syndrome has been described as a means of controlling these arrhythmias and recent reports describe elimination of the Brugada phenotype with ablation. We describe a unique case in which a patient developed inferior J waves with an early repolarization-type electrocardiogram following successful epicardial infundibular substrate ablation (which eliminated the Brugada syndrome electrocardiogram on ajmaline challenge). We discuss the likely underlying pathophysiology responsible for this phenomenon, its relationship to the anatomic obstacles encountered during epicardial ablation, and the implications for long-term arrhythmic risk.

Pericardiocentesis ­ How to do it.

Pericardiocentesis is an important diagnostic and therapeutic technique, with the potential for significant morbidity and mortality if performed incorrectly. This article attempts to cover the anatomy, preparation, and techniques necessary to successfully perform pericardiocentesis.

Arrhythmic Mitral Valve Prolapse Syndrome and Ventricular Arrhythmias: A Comprehensive Review and the Role of Catheter Ablation.

Mitral valve prolapse (MVP) affects 2-3% of the general population, and despite its benign prognosis overall, it is associated with sudden death in a small subset of patients. The term "arrhythmic MVP syndrome" (AMVPS) refers to the presence of frequent or complex ventricular arrhythmias, commonly reported in female patients with a stereotypical phenotype including bileaflet myxomatous disease, ECG repolarisation abnormalities in inferior leads, mitral annular disjunction, and significant fibrosis in the inferolateral LV and papillary muscles. Modern imaging technologies have led to the identification of new risk factors that have been implemented in recent risk stratification guidelines; however, screening for patients with MVP who are at risk of sudden cardiac death (SCD) remains challenging. In addition, there is a limited amount of data on the outcomes of different treatment approaches in AMVP and no specific indication for targeted or disease-modifying therapies within current guidelines. Potential arrhythmic substrates in patients with AMVP syndrome have been the subject of interest in previous studies, with areas consisting of fibrosis at the papillary muscle level and the Purkinje system. Premature ventricular contractions (PVCs) originating from these areas have been shown to play an important role as triggers for ventricular fibrillation and SCD in patients with AMVP. Catheter ablation has emerged as a potential treatment modality in patients with MVP and ventricular arrhythmias (VAs), targeting arrhythmic substrates and triggering PVC foci. The aim of this review is to explore the role of catheter ablation in treating patients with AMVP.