Kurt C Roberts-Thomson

• MBBS, PhD, FRACP
• Royal Adelaide Hospital

Background Remote monitoring (RM) of implantable cardioverter defibrillators (ICD) has been widely adopted as the standard follow-up strategy [1]. Observational data [2,3] has suggested morbidity and mortality reduction associated with RM compared to traditional in-person ICD follow-up, however, randomised controlled trials (RCTs) demonstrate heter...

Background Inpatient monitoring is recommended for sotalol initiation. Objective The purpose of this study was to assess the safety of outpatient sotalol commencement. Methods This is a multicenter, retrospective, observational study of patients initiated on sotalol in an outpatient setting. Serial electrocardiogram monitoring at day 3, day 7, 1...

Background: Fidelity of electrogram sensing may reduce false alerts from insertable cardiac monitor (ICM). Objective: To assess impact of vector length, implant angle and patient factors on electrogram sensing using surface electrocardiogram (EKG) mapping. Methods: Twelve separate precordial single-lead surface EKGs were acquired from 150 part...

Importance: Randomised trials have shown that catheter ablation (CA) is superior to medical therapy for ventricular tachycardia (VT) largely in patients with ischaemic heart disease. Whether this translates to patients with all forms and stages of structural heart disease (SHD-e.g., non-ischaemic heart disease) is unclear. This trial will help cla...

Background Most modern cardiac implantable electronic device (CIED) systems are now compatible with magnetic resonance imaging (MRI) scans. The requirement for both pre- and post-MRI CIED checks imposes significant workload to the cardiac electrophysiology service. Here, we sought to determine the burden of CIED checks associated with MRI scans. M...

Background Little data exists on electrogram sensing in current generation of miniaturized insertable cardiac monitors (ICMs). Objective To compare the sensing capability of ICM with different vector length: Medtronic Reveal LINQ (~40 mm) vs. Biotronik Biomonitor III (BM-III, ~70 mm). Methods De-identified remote monitoring transmissions from n =...

Background Requests from the emergency department (ED) for cardiac implantable electronic device (CIED) checks constitute a large workload for cardiac electrophysiology services. We sought to determine the yield of, and clinical characteristics associated with, clinically relevant (remarkable) issues from ED CIED checks. Methods Consecutive CIED c...

Objectives This study sought to evaluate the role of cardiac afferent reflexes in atrial fibrillation (AF). Background Efferent autonomic tone is not associated with atrial remodeling and AF persistence. However, the role of cardiac afferents is unknown. Methods Individuals with nonpermanent AF (n = 48) were prospectively studied (23 in the in-AF...

Introduction Atrial fibrillation (AF) is associated with significantly impaired quality-of-life. Iron deficiency (ID) is prevalent in patients with AF. Correction of ID in other patient populations with intravenous iron supplementation has been shown to be a safe, convenient and effective way of improving exercise tolerance, fatigue and quality-of-...

Background Indigenous Australians experience a greater burden of AF. Whether this is in-part due to differences in arrhythmogenic structures that appear to contribute to AF differences amongst other ethnicities is not known. Methods We studied forty individuals matched for ethnicity and other AF risk factors. Computed tomography imaging was used t...

Background The epidemiology of atrial fibrillation (AF) amongst Indigenous populations remains poorly characterised. We studied hospitalisations for AF in Central Australia, the most populous Indigenous region in the country. Methods Patients with a diagnosis of AF admitted to Alice Springs Hospital, the only secondary health care facility and pro...

Background P-wave visibility is useful for diagnosis of atrial arrhythmias via insertable cardiac monitors (ICM). Purpose To compare the sensing capability of ICM with different vector length: Medtronic REVEAL LINQ (45mm) vs. Biotronik Biomonitor BMIII (75mm). Methods We accessed de-identified remote monitoring transmissions from n=40 patients wi...

Objective Prior studies have demonstrated that anticoagulation underutilisation for atrial fibrillation (AF) and elevated stroke risk is common. However, there is little data on factors associated with appropriate anticoagulation, particularly in Indigenous Australians who face a disproportionate burden of AF and stroke. We thus sought to determine...

D-PO04-037 10.1016/j.hrthm.2020.04.009

Aims: There is growing evidence that magnetic resonance imaging (MRI) scanning in patients with non-conditional cardiac implantable electronic devices (CIEDs) can be performed safely. Here, we aim to assess the safety of MRI in patients with non-conditional CIEDs. Methods and results: English scientific literature was searched using PubMed/Embas...

Background Obesity is prevalent in Indigenous populations who exhibit significant differences in body fat composition. While excess regional adiposity can be partially inferred from clinical measurements, noninvasive imaging allows for direct quantification of specific fat depots. Epicardial fat is a visceral adipose tissue that has been strongly a...

Background: Studies have shown that suboptimal anticoagulation quality, as measured by time in therapeutic range (TTR), affects a significant percentage of patients with atrial fibrillation (AF). However, TTR has not been previously characterised in Indigenous Australians who experience a greater burden of AF and stroke. Method: Indigenous and n...

Introduction : An 88 year old female with permanent Atrial Fibrillation (AF) and normal QT presented to the emergency department following a witnessed collapse. Her Permanent Pacemaker (PPM) was interrogated. Methods : To report the rare occurrence of prolonged Ventricular Fibrillation (VF) spontaneous termination. Result : PPM Interrogation reveal...

Background Atrial fibrillation (AF) is common after pacemaker implantation. However, the impact of pacemaker algorithms in AF prevention is not well understood. Objective The purpose of this study was to evaluate the role of pacing algorithms in preventing AF progression. Methods A systematic search of articles using the PubMed and Embase databas...

Ventricular arrhythmias are one of the leading causes of death in patients with a prior myocardial infarction. Implantable cardioverter-defibrillators (ICDs) are very effective in the prevention of sudden cardiac death but the risk of recurrence remains an issue since defibrillation does not alter the underlying substrate. Recurrent ICD shocks are...

Purpose: Protected channels of surviving myocytes in late postinfarction ventricular scar predispose to ventricular tachycardia (VT). However, only a few patients develop VT spontaneously. We studied differences in electric remodeling and protected channels in late postinfarction patients with and without spontaneous VT. Methods: Patients with i...

Background It has been suggested that ethnicity can make a significant difference to the likelihood of thromboembolic stroke related to atrial fibrillation. Ethnic differences have been shown to alter inflammatory and haemostatic factors; however, this may all be confounded by differences in cardiovascular risk factors between different ethnicity....

Background: A number of cardiovascular diseases have been linked with bone health and an increased risk of osteoporotic fracture. Whether atrial fibrillation (AF) is associated with subsequent fracture risk is not known. Methods: Administrative, clinical and hospitalisation information were linked over a 14-year period. From this longitudinal, p...

Heart rate variability (HRV) modulates dynamics of ventricular repolarization. A diminishing value of HRV is associated with increased vulnerability to life-threatening ventricular arrhythmias, however the causal relationship is not well-defined. We evaluated if fixed-rate atrial pacing that abolishes the effect of physiological HRV, will alter ven...

Background: In ventricular scar, impulse spread is slow because it traverses split and zigzag channels of surviving muscle. We aimed to evaluate scar electrograms to determine their local delay (activation time) and inequality in voltage splitting (entropy), and their relationship to channels. We reasoned that unlike innocuous channels, which are...

Introduction: The arrhythmogenic characteristics of surviving myocyte channels in ventricles with post-infarct scarring and sustained monomorphic ventricular tachycardia (VT) compared to post-infarct ventricles without spontaneous VT are unknown. Methods: Patients with ischemic cardiomyopathy (ICM) and recurrent VT (VT patients; n = 22; EF 32 ± 8 %...

Aims: In ventricular scar, the impulse spread is slow as it traverses multiple split and zigzag channels of surviving muscle. We aimed to evaluate electrograms in the scar to determine their local delay in relation to the onset of ventricular activation (activation time) and inequality in voltage splitting (entropy), and their relationship to chann...

Background: A diminishing value of heart rate variability (HRV) robustly increases vulnerability to life-threatening ventricular arrhythmias, yet the electrophysiological mechanism of this dynamic relationship is still not well understood. We evaluated if fixed-rate atrial pacing, that abolishes the effect of physiological HRV, will modulate ventri...

Objectives This study sought to determine the differences between the prothrombotic properties and chamber characteristics in patients with lone atrial fibrillation (AF) and those with AF and comorbidities. Background Thromboembolic risk is increased in patients with AF; however, whether this is due to AF per se or its comorbidities remains unclea...

Objectives: The purpose of this study was to quantify the magnitude of association between incremental increases in body mass index (BMI) and the development of incident, post-operative, and post-ablation atrial fibrillation (AF). Background: Obesity has been estimated to account for one-fifth of all AF and approximately 60% of recent increases...

Remote monitoring (RM) of implantable cardioverter-defibrillators (ICD) is an established technology integrated into clinical practice. One recent randomized controlled trial (RCT) and several large device database studies have demonstrated a powerful survival advantage for ICD patients undergoing RM compared with those receiving conventional in-of...

Atrial fibrillation (AF) is a leading cause of preventable stroke in Australia. Given that anticoagulation therapy can significantly reduce this stroke risk, we sought to characterise anticoagulation use in Indigenous and non-Indigenous Australians with AF. Administrative, clinical and prescription data from patients with AF were linked. Anticoagul...

Background Rotors are postulated to maintain cardiac fibrillation. Despite the importance of bipolar electrograms in clinical electrophysiology, few data exist on the properties of bipolar electrograms at rotor sites. The pivot of a spiral wave is characterized by relative uncertainty of wavefront propagation direction compared to the periphery. Th...

Background Nonvalvular atrial fibrillation (AF) confers a five-fold increased risk of stroke. Whether catheter ablation (CA) subsequently decreases prothrombotic risk is unknown. Objective We sought to assess the long-term effects of CA for AF on prothrombotic risk. Methods Fifty-seven patients undergoing CA for AF were prospectively studied. Pla...

Objective To examine the prevalence of atrial fibrillation (AF) and cardiac structural characteristics in Indigenous and non-Indigenous Australians. Design Retrospective cross-sectional study linking clinical, echocardiography and administrative databases over a 10-year period. Setting A tertiary, university teaching hospital in Adelaide, Australia...

Macroreentrant atrial tachycardia is a common complication following surgery for congenital heart disease (CHD), and is often highly symptomatic with potentially significant hamodynamic consequences. Medical management is often unsuccessful, requiring the use of invasive procedures. The cavotricuspid isthmus dependent flutter is the most common cir...

Patients with atrial fibrillation (AF) are at an increased risk of thromboembolism and stroke primarily from the development of thrombi within the left atrial. Pathological changes in blood constituents and atrial endothelial damage promote the left atrial thrombus formation. It is not known whether factors predisposing to left atrial thrombus form...

-Surviving myocytes within scar may form channels that support ventricular tachycardia (VT) circuits. There is little data on the properties of channels that comprise VT circuits and those which are non-VT supporting channels. -In 22 patients with ischemic cardiomyopathy and VT, high-density mapping was performed with the PentaRay™ catheter and Ens...

-Inflammation has been linked to the genesis of stroke in atrial fibrillation (AF) and is implicated in early recurrent arrhythmia after AF ablation. We aimed to define the time course of inflammation, myocardial injury and prothrombotic markers following radiofrequency (RF) ablation for AF and its relation to AF recurrence. -Ninety consecutive AF...

Ventricular tachycardia (VT) is generally observed in the setting of structural heart disease. However, in a proportion of patients presenting with VT, the routine diagnostic modalities demonstrate no overt myocardial abnormality. These arrhythmias have been called idiopathic VTs. They consist of various subtypes that have been defined by their ana...

Purpose: Current substrate based ablation strategies for ventricular tachycardia (VT) advocate targeting all excitable abnormal ventricular electrograms within the scar. However only a fraction of these electrograms populate the VT supporting channels. We hypothesized that the electrogram properties in the standard model can identify information co...

Open-irrigated radiofrequency catheter ablation (oiRFA) of atrial fibrillation (AF) imposes a volume load and risk of pulmonary edema. We sought to assess the effect of volume administration during ablation on left atrial (LA) pressure and B-type natriuretic peptide (BNP). LA pressure was measured via transseptal sheath at the beginning and end of...

-Atrial fibrillation (AF) ablation is an established therapy; however, limited data is available on associated complications. This systematic review determines the incidence and potential predictors of acute complications. -Electronic searches were conducted in MEDLINE and EMBASE for English scientific literature up to the 18(th) June 2012. 2065-re...

Recent community-based research has linked aortic stiffness to the development of atrial fibrillation. We posit that aortic stiffness contributes to adverse atrial remodeling leading to the persistence of atrial fibrillation following catheter ablation in lone atrial fibrillation patients, despite the absence of apparent structural heart disease. H...

QT variability (QTV) signifies repolarization lability and increased QTV is a risk predictor for sudden cardiac death. The aim of this study was to investigate the role of autonomic nervous system activity on QTV. The study was performed in 29 subjects: 10 heart failure patients with spontaneous ventricular tachycardia [HFVT(+)], 10 heart failure p...

Introduction: Surviving myocytes within scar may form channels that become critical component of a ventricular tachycardia (VT) reentrant circuit. There is little data on the physiognomies of channels that comprise VT circuits and those which are non-VT channels. Methods: Twenty-two patients with ischemic cardiomyopathy (LVEF 32±8%) and multiple in...

Purpose: Reverse remodeling of the left atrium has been demonstrated following atrial fibrillation (AF) ablation. Whilst we have previously described the association between pericardial fat and left atrial volumes, pericardial fat has not been studied in relation to reverse remodelling. Furthermore, the significance of changes in pericardial fat vo...

-Myocardial infarction (MI) is associated with the development of atrial fibrillation (AF). We aimed to characterize the atrial abnormalities due to MI and determine the role of ischemia to the AF substrate. Method and Results-Forty-four sheep were studied. MI was induced by occlusion of the circumflex artery (LCX) or left anterior descending arter...

Implantable cardioverter defibrillators (ICD) have been demonstrated to reduce mortality in survivors of life-threatening arrhythmias (secondary prevention) and in patients at increased risk of sudden cardiac death (primary prevention). Other nations have reported significant increases in ICD use in recent years. To investigate Australian nationwid...

Background: Carto-Sound integrates 2D intra-cardiac ultrasound imaging into a 3D environment to allow left atrial mapping from the right atrium without fluoroscopic assistance. We conducted an open randomized controlled study to compare procedural, clinical and accuracy parameters between CT integrated Carto-Sound and electro-anatomic mapping (EAM...

Although most of the additional increases in coronary heart disease morbidity and mortality are estimated to occur outside developed regions such as North America and Europe, few nationwide studies have been published of acute myocardial infarction (MI) epidemiology from other regions. We thus sought to expand the global data regarding MI trends. N...

Although conferences are important vehicles for discussing scientific findings, the translation of presented research into peer-reviewed manuscripts is a crucial subsequent step in the research process. Given the evolving subspecialization of cardiology, we sought to characterize the temporal and comparative outcomes of abstracts presented at a sub...

In the past decade, catheter ablation has become an established therapy for symptomatic atrial fibrillation (AF). Until very recently, few data have been available to guide the clinical community on the outcomes of AF ablation at ≥3 years of follow-up. We aimed to systematically review the medical literature to evaluate the long-term outcomes of AF...

Ventricular activation at right ventricular apex should precede activation elsewhere in right ventricle in clockwise bundle-branch re-entry. Additionally, entrainment pacing from His catheter should have long postpacing interval (PPI) in bundle-branch re-entry. We demonstrate a case where paradoxical findings challenged the diagnosis of clockwise b...

Background: Targeting complex fractionated electro-grams (CFAE) is becoming a popular ablation technique. However, the temporal stability of CFAE and its impact on interpretation of sequential CFAE results has recently been brought into question. Methods: Twelve patients underwent sequentially acquired left atrial CFAE signal maps. Eight seconds of...