Impact of device length on electrogram sensing in miniaturized insertable cardiac monitors.

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).

Autonomic Afferent Dysregulation in Atrial Fibrillation.

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.

Rationale and design of the IRON-AF study: a double-blind, randomised, placebo-controlled study to assess the effect of intravenous ferric carboxymaltose in patients with atrial fibrillation and iron deficiency.

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-life.

Left atrial, pulmonary vein, and left atrial appendage anatomy in Indigenous individuals: Implications for atrial fibrillation.

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.

Atrial Fibrillation in Remote Indigenous and Non-Indigenous Individuals Hospitalised in Central Australia.

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 provider of cardiac care in remote Central Australia, were identified from 2006 to 2016.

Epicardial and subcutaneous adipose tissue in Indigenous and non-Indigenous individuals: Implications for cardiometabolic diseases.

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 associated with cardiometabolic disease in other populations.

Implication of ventricular pacing burden and atrial pacing therapies on the progression of atrial fibrillation: A systematic review and meta-analysis of randomized controlled trials.

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.

Catheter Ablation of Post-Infarct VT: Mechanisms, Strategies and Outcomes.

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 distressing and are associated with an increase in mortality.

Influence of ethnic background on left atrial markers of inflammation, endothelial function and tissue remodelling.

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. The impact of different ethnicities on the thrombogenic profile is not known.

Electrophysiologic features of protected channels in late postinfarction patients with and without spontaneous ventricular tachycardia.

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.

Atrial fibrillation and risk of hip fracture: A population-based analysis of 113,600 individuals.

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.

Effect of Loss of Heart Rate Variability on T-Wave Heterogeneity and QT Variability in Heart Failure Patients: Implications in Ventricular Arrhythmogenesis.

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 ventricular repolarization wavefronts and is relevant to ventricular arrhythmogenesis.

Development of Time- and Voltage-Domain Mapping (V-T-Mapping) to Localize Ventricular Tachycardia Channels During Sinus Rhythm.

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 often short with multiple side branches, ventricular tachycardia (VT) supporting channels have very slow impulse spread and possess low entropy because of their longer protected length and relative lack of side-branching.

Thrombogenic Risk in Patients With Atrial Fibrillation: Importance of Comorbid Conditions and Intracardiac Changes.

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 unclear.

Methods: A total of 87 patients undergoing ablation were prospectively recruited for the study, including 30 patients with lone AF, 30 patients with AF and comorbidities in sinus rhythm, and 27 patients with left-sided accessory pathways as controls.

Obesity and the Risk of Incident, Post-Operative, and Post-Ablation Atrial Fibrillation: A Meta-Analysis of 626,603 Individuals in 51 Studies.

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 in population AF incidence. From a public health perspective, obesity, therefore, is a modifiable risk factor that could be profitably targeted.

Remote Monitoring of Implantable Cardioverter-Defibrillators: A Systematic Review and Meta-Analysis of Clinical Outcomes.

Background: 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-office (IO) follow-up.

Objectives: This study sought to conduct a systematic published data review and meta-analysis of RCTs comparing RM with IO follow-up.

Underuse and overuse of anticoagulation for atrial fibrillation: A study in Indigenous and non-Indigenous Australians.

Background: 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.

Methods: Administrative, clinical and prescription data from patients with AF were linked.

Origin and characteristics of high Shannon entropy at the pivot of locally stable rotors: insights from computational simulation.

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.