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Aims: Obesity is associated with higher electrical cardioversion (ECV) failure in persistent atrial fibrillation (PeAF). For ease-of-use, many centers prefer patches over paddles. We assessed the optimum modality and shock vector, as well as the safety and efficacy of the Manual Pressure Augmentation (MPA) technique., Methods: Patients with obesity (BMI ≥ 30) and PeAF undergoing ECV using a biphasic defibrillator were randomized into one of four arms by modality (adhesive patches or handheld paddles) and shock vector (anteroposterior [AP] or anteroapical [AA]). If the first two shocks (100 and 200 J) failed, then patients received a 200-J shock using the alternative modality (patch or paddle). Shock vector remained unchanged. In an observational substudy, 20 patients with BMI of 35 or more, and who failed ECV at 200 J using both patches/paddles underwent a trial of MPA., Results: In total, 125 patients were randomized between July 2016 and March 2018. First or second shock success was 43 of 63 (68.2%) for patches and 56 of 62 (90.3%) for paddles (P = 0.002). There were 20 crossovers from patches to paddles (12 of 20 third shock success with paddles) and six crossovers from paddles to patches (three of six third shock success with patches). Paddles successfully cardioverted 68 of 82 patients compared with 46 of 69 using patches (82.9% vs 66.7%; P = 0.02). Shock vector did not influence first or second shock success rates (82.0% AP vs 76.6% AA; P = 0.46). MPA was successful in 16 of 20 (80%) who failed in both (patches/paddles), with 360 J required in six of seven cases., Conclusion: Routine use of adhesive patches at 200 J is inadequate in obesity. Strategies that improve success include the use of paddles, MPA, and escalation to 360 J., (© 2018 Wiley Periodicals, Inc.)

Cardiac arrhythmias are frequently seen in patients with dilated cardiomyopathy (DCM) and can precipitate heart failure and death. In patients with non-ischaemic DCM, evidence for the benefit of an implantable cardioverter-defibrillator (ICD) for primary prevention of sudden cardiac death has recently been questioned. Algorithms devised to identify high-risk individuals who might benefit most from ICD implantation have focussed on clinical criteria with little attention paid to the underlying aetiology of DCM. Malignant ventricular arrhythmias often occur as a nonspecific consequence of DCM but can also be a primary manifestation of disease in heritable forms of DCM and may precede DCM onset. We undertook a literature search and identified 11 genes that have been associated with DCM and ventricular arrhythmias in multiple kindreds. Many of these genes fall into a diagnostic grey zone between left-dominant arrhythmogenic right ventricular cardiomyopathy and arrhythmic DCM. Genes associated predominantly with arrhythmic DCM included LMNA and SCN5A, as well as the more recently-reported DCM disease genes, RBM20, FLNC, and TTN. Recognition of arrhythmic DCM genotypes is important, as this may impact on clinical management. In particular, prophylactic ICD implantation and early referral for heart transplantation may be indicated in genotype-positive individuals. Collectively, these findings argue in favour of including genetic testing in standard-of-care management of familial DCM. Further studies in genotyped patient cohorts are required to establish the long-term health and economic benefits of this strategy., (Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Ventricular fibrillation (VF) is a common and life-threatening arrhythmia resulting in sudden cardiac death (SCD). Due to the inherent challenges of mapping VF in humans, the underlying mechanisms that initiate and sustain this common arrhythmia are still poorly understood. In high-risk patients and survivors of SCD, implantable cardioverter defibrillators (ICD) play a central role in treating VF episodes, however, ICDs do not prevent VF recurrences and patients remain at risk of electrical storm and multiple shocks that are often refractory to escalation of medical therapy. More recently, the utility of catheter ablation (CA) has extended to the treatment of VF storms. This review will focus on updates in elucidating the mechanism of VF leading into the role and indication of CA as a treatment strategy., (Copyright © 2018. Published by Elsevier B.V.)

Despite advancements in prevention and treatment, sudden cardiac death (SCD) remains a leading cause of mortality and is responsible for approximately half of all deaths from cardiovascular disease. Outcomes continue to remain poor following a sudden cardiac arrest, with most individuals not surviving. Although coronary heart disease remains the dominant underlying condition, our understanding of SCD is improving through greater knowledge of clinical risk factors, cardiomyopathies, and primary arrhythmic disorders. However, despite a growing wealth of information from studies in North America, Europe, and Japan, data from other global regions (and particularly from low-and middle-income countries) remains scarce., (Copyright © 2018. Published by Elsevier B.V.)

Objectives: Mitral valve prolapse (MVP) is commonly observed as a benign finding. However, the literature suggests that it may be associated with sudden cardiac death (SCD). We performed a meta-analysis and systematic review to determine the: (1) prevalence of MVP in the general population; (2) prevalence of MVP in all SCD and unexplained SCD; (3) incidence of SCD in MVP and (4) risk factors for SCD., Methods: The English medical literature was searched for: (1) MVP community prevalence; (2) MVP prevalence in SCD cohorts; (3) incidence SCD in MVP and (4) SCD risk factors in MVP. Thirty-four studies were identified for inclusion. This study was registered with PROSPERO (CRD42018089502)., Results: The prevalence of MVP was 1.2% (95% CI 0.5 to 2.0) in community populations. Among SCD victims, the cause of death remained undetermined in 22.1% (95% CI 13.4 to 30.7); of these, MVP was observed in 11.7% (95% CI 5.8 to 19.1). The incidence of SCD in the MVP population was 0.14% (95% CI 0.1 to 0.3) per year. Potential risk factors for SCD include bileaflet prolapse, ventricular fibrosis complex ventricular ectopy and ST-T wave abnormalities., Conclusion: The high prevalence of MVP in cohorts of unexplained SCD despite low population prevalence provides indirect evidence of an association of MVP with SCD. The absolute number of people exposed to the risk of SCD is significant, although the incidence of life-threatening arrhythmic events in the general MVP population remains low. High-risk features include bileaflet prolapse, ventricular fibrosis, ST-T wave abnormalities and frequent complex ventricular ectopy., Trial Registration: PROSPERO (CRD42018089502)., Competing Interests: Competing interests: JMK reports having received research funding from St Jude Medical, Biosense-Webster, Medtronic and Boston Scientific. Dr Sanders reports having served on the advisory board of Biosense-Webster, Medtronic, CathRx and St Jude Medical. PS reports having received lecture and/or consulting fees from Biosense-Webster, Medtronic, St Jude Medical, and Boston Scientific. PS reports having received research funding from Medtronic, St Jude Medical, Boston Scientific, Biotronik and Sorin., (© Author(s) (or their employer(s)) 2019. No commercial re-use. See rights and permissions. Published by BMJ.)

Introduction: Several ECG markers are postulated to represent underlying atrial remodelling and have been associated with ischemic stroke. P-wave terminal force in lead V 1 (PTFV 1 ) is one such marker. We examined the factors that contribute to the reliability of PTFV 1 and its association with ischemic stroke., Material and Methods: Four hundred and thirty-five patients that presented with an ischemic stroke or transient ischemic attack (TIA) were identified through a prospectively maintained multi-site institutional stroke database. Control group consisted of age matched patients without prior history of an ischemic stroke or TIA. All patients underwent a 12-lead ECG and 24-hour Holter monitoring during the study period to exclude atrial fibrillation., Results: Morphology consistent with PTFV 1 occurred commonly in both the stroke/TIA and control groups. There was no significant difference in the median PTFV 1 value between the stroke 3.96 mV ms [Interquartile range (IQR) 2.78-5.58] and control 4.23 mV ms [IQR 2.91-5.57] groups. Measurements of PTFV 1 demonstrated excellent intra-observer reliability on assessment of the same P-wave (Intra class correlation (ICC) 0.91, p < 0.001) with narrow limits of agreement 2.21 to -2.95 mV ms. A change in the P wave assessed led to a significant reduction in reliability (ICC 0.79, p < 0.001). Inter-observer, inter P-wave assessment demonstrated further reduction in reliability (ICC 0.68, p < 0.002) with wide limits of agreement 6.17 to -5.78 mV ms, indicating significant under and overestimation of PTFV 1 ., Conclusion: The utility of PTFV 1 as a clinical marker for ischemic stroke is limited by the reduction in reliability associated with inter-observer and inter P-wave measurements., (Copyright © 2018 Elsevier Inc. All rights reserved.)

Background: Sleep-disordered breathing (SDB) is highly prevalent in patients with atrial fibrillation (AF) and its treatment can improve rhythm control. Polysomnography (PSG) is the gold standard for the diagnosis of SDB but its high cost and limited availability constrain its role as a standard SDB screening tool. We sought to assess the diagnostic utility of overnight oximetry in predicting SDB in AF patients., Methods: We analyzed prospectively collected data on 439 patients with documented AF (62% paroxysmal AF) who underwent PSG. Overnight oximetry was used to determine the oxygen desaturation index (ODI, number of desaturation/h) by a novel automated computer algorithm. ODI was validated against PSG derived apnea-hypopnea index (AHI)., Results: The sample consisted of 69% men with a mean age of 59.9 ± 11.3 years and body mass index of 30 ± 5 kg/m 2 . The median AHI was 9.5 [3.6-21.0]/h and the prevalence of moderate (AHI 15-29/h) and severe SDB (AHI ≥ 30/h) was 17.3% and 16.6% respectively. The ODI was able to detect moderate-to-severe SDB (AHI ≥ 15/h; area under the receiver-operating-characteristic curve (AUC): 0.951, 95% CI: 0.929-0.972) and severe SDB (AHI ≥ 30/h; 0.932, 95% CI: 0.895-0.968) with high diagnostic accuracy. An ODI cut-off of 4.1/h resulted in a 91% sensitivity and 83% specificity in discriminating between patients with and without AHI ≥ 15/h. An ODI of 7.6/h yielded a sensitivity and specificity for AHI ≥ 30/h of 89% and 83%, respectively., Conclusions: ODI derived from a simple and low-cost overnight oximetry can be used as an accessible and reliable screening tool, particularly to rule out SDB., (Copyright © 2018 Elsevier B.V. All rights reserved.)

Aims: Atrial fibrillation (AF) is a progressive disease. Obesity is associated with progression of AF. This study evaluates the impact of weight and risk factor management (RFM) on progression of the AF., Methods and Results: As described in the Long-Term Effect of Goal-Directed Weight Management in an Atrial Fibrillation Cohort: A Long-Term Follow-Up (LEGACY) Study, of 1415 consecutive AF patients, 825 had body mass index ≥ 27 kg/m2 and were offered weight and RFM. After exclusion, 355 were included for analysis. Weight loss was categorized as: Group 1 (<3%), Group 2 (3-9%), and Group 3 (≥10%). Change in AF type was determined by clinical review and 7-day Holter yearly. Atrial fibrillation type was categorized as per the Heart Rhythm Society consensus. There were no differences in baseline characteristic or follow-up duration between groups (P = NS). In Group 1, 41% progressed from paroxysmal to persistent and 26% from persistent to paroxysmal or no AF. In Group 2, 32% progressed from paroxysmal to persistent and 49% reversed from persistent to paroxysmal or no AF. In Group 3, 3% progressed to persistent and 88% reversed from persistent to paroxysmal or no AF (P < 0.001). Increased weight loss was significantly associated with greater AF freedom: 45 (39%) in Group 1, 69 (67%) in Group 2, and 116 (86%) in Group 3 (P ≤ 0.001)., Conclusion: Obesity is associated with progression of the AF disease. This study demonstrates the dynamic relationship between weight/risk factors and AF. Weight-loss management and RFM reverses the type and natural progression of AF.

Objectives: This study sought to compare electrocardiogram (ECG) variants in athletic and arrhythmogenic right ventricular cardiomyopathy (ARVC) cohorts matched for the confounders of age, sex, and ethnicity., Background: Anterior T-wave inversion (TWI V1-V4 ) is a common electrocardiographic finding in both athletes and patients with ARVC, and is a frequent conundrum in the setting of pre-participation screening. J-point elevation (JPE) has been proposed as an accurate means of identifying athletes, whereas disease markers, including premature ventricular contractions (PVCs) and low-voltage signals, have been associated with ARVC., Methods: This study examined 200 subjects with TWI V1-V4, including 100 healthy athletes and 100 ARVC patients matched 1:1 for age, sex, and ethnicity (age: 21 ± 5 years for athletes vs. 22 ± 5 years for ARVC patients; 47% male; 97% Caucasian). The presence of TWI, JPE, PVCs, and left ventricular hypertrophy (LVH) were assessed., Results: JPE was observed in 27% of athletes versus 16% of ARVC patients (p = 0.09). Thus, JPE had poor specificity (27%) and accuracy (60%) in identifying healthy athletes. In contrast, ARVC patients demonstrated a greater prevalence of precordial TWI beyond lead V 3 (34% vs. 8%; p < 0.001), inferior TWI (31% vs. 3%; p < 0.001), PVCs (18% vs. 0%; p < 0.001), and lower LVH scores (S V1  + R V5 ; 19 ± 1 mm vs. 30 ± 1 mm; p < 0.001). These combined factors provided more reliable differentiation between health and disease (specificity 82%, accuracy 81%)., Conclusions: PVCs and low QRS voltages are more prevalent among ARVC patients than athletes, whereas JPE is a relatively poor discriminator of health and disease when the confounders of age, sex, and ethnicity are considered., (Copyright © 2018. Published by Elsevier Inc.)

Objectives: The aims of the study were to characterize: 1) electrical and electroanatomical remodeling in patients with atrial fibrillation (AF) with obesity; and 2) the impact of epicardial fat depots on adjacent atrial tissue., Background: Obesity is associated with an increased risk of AF., Methods: A total of 115 patients with AF who underwent AF ablation were screened. After exclusion, 26 patients were divided into 2 groups (obese: body mass index [BMI] ≥27 kg/m 2 and reference: BMI <27 kg/m 2 ). They underwent cardiac magnetic resonance (CMR) imaging and electroanatomic mapping of the left atrium (LA) in sinus rhythm before AF ablation. Atrial and ventricular epicardial adipose tissue (EAT) were assessed by CMR. The following electrophysiological parameters were assessed: global and regional voltage, conduction velocity (CV), electrogram fractionation, and CV heterogeneity. In addition, the regional relationship between LA EAT depots and the electrophysiological substrate was evaluated., Results: The BMIs of the obese and reference groups were 30.2 ± 2.6 and 25.2 ± 1.3 kg/m 2 , respectively (p < 0.001). There was no difference in the left ventricular ejection fraction and a nonsignificant increase in LA size with obesity. Obesity was associated with increase in all measures of EAT (p < 0.05), with a predominant distribution adjacent to the posterior LA and the atrioventricular groove. Obesity was associated with reduced global CV (0.86 ± 0.31 m/s vs. 1.26 ± 0.29 m/s; p < 0.001), with a nonsignificant increase in conduction heterogeneity (p = 0.10), increased fractionation (54 ± 17% vs. 25 ± 10%; p < 0.001), and regional alteration in voltage (p < 0.001). Although the global LA voltage was preserved, there was greater voltage heterogeneity (p = 0.001) and increased low-voltage areas (13.9% vs. 3.4%; p < 0.001) in the obese group compared with the reference group. The low voltage areas were predominantly seen in the posterior and/or inferior LA, which was similar to location of EAT on CMR imaging. Among various measures of obesity, LA EAT volume correlated best with posterior LA fractionation (r 2  = 0.55 for LA EAT volume vs. r 2  = 0.36 for BMI) and CV (r 2  = 0.31 for LA EAT volume vs. r 2  = 0.22 for BMI)., Conclusions: Obesity is associated with electroanatomical remodeling of the atria, with areas of low voltage, conduction slowing, and greater fractionation of electrograms. These changes were more pronounced in regions adjacent to epicardial fat depots, which suggested a role for fat depots in the development of the AF substrate., (Crown Copyright © 2018. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to determine the impact of regular alcohol consumption on left atrial (LA) mechanical and reservoir function., Background: Earlier studies suggest that regular alcohol intake is associated with increased atrial fibrillation (AF) and LA dilatation., Methods: This study prospectively enrolled 160 patients with paroxysmal or persistent AF to undergo 3-T cardiac magnetic resonance (CMR) imaging in sinus rhythm. Patients self-reported alcohol consumption in standard drinks (∼12 g alcohol) per week over the preceding 12 months and were categorized into 4 groups: 1) lifelong nondrinkers; 2) mild drinkers (3 to 10 standard drinks/week); 3) moderate drinkers (11 to 20 standard drinks/week); 4) heavy drinkers (>20 standard drinks/week). Permanent AF and cardiomyopathy were excluded. On CMR, maximum LA volume (LA max ) and minimum LA volume (LA min ), global LA emptying fraction (LAEF) as (LA max  - LA min ) / LA max , and LA reservoir function as (LA max  - LA min ) / LA min were calculated., Results: Regular alcohol consumption (mean 15.8 ± 6.9 standard drinks/week, n = 120) was associated with larger LA size (LA volume index 50 ± 13 ml/m 2 vs. 43 ± 12 ml/m 2 ; p = 0.005), reduction in LAEF (40 ± 14% vs. 52 ± 15%; p < 0.001), and reduction in reservoir function (77 ± 48% vs. 119 ± 63%; p < 0.001) compared with lifelong nondrinkers (n = 40). There were progressive dose-related impairments in LAEF (mild 45.4 ± 13.5% vs. moderate 39.1 ± 14.7% vs. heavy drinkers 35.6 ± 12.6%; p < 0.01) and reservoir function (mild 95.8 ± 55.6% vs. moderate 74.8 ± 47.1% vs. heavy drinkers 61.7 ± 34.4%; p < 0.01). Predictors of atrial mechanical dysfunction included weekly alcohol intake (p = 0.001), older age (p = 0.018), and persistent AF (p = 0.016), but not binge drinking or beverage type., Conclusions: In patients with AF, habitual alcohol consumption is associated with significantly increased LA size and atrial mechanical dysfunction compared with nondrinkers., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: Several techniques have been utilized for the ablation of persistent (P) and long-standing persistent (LsP) atrial fibrillation (AF); however, the best approach of substrate ablation remains poorly defined. This study aims to examine the impact of ablation approach on outcomes associated with P or LsP AF ablation by conducting a meta-analysis and regression on contemporary literature., Methods and Results: A systematic literature review was conducted up to 29 July 2015 for scientific literature reporting on outcomes associated with P or LsP AF ablation. One hundred and thirteen studies reported outcomes in a total of 18 657 patients undergoing various ablation approaches for the treatment of P-LsP AF between 2001 and 2015. The point efficacy estimate of a single-AF ablation procedure without the use of anti-arrhythmic drugs was 43% (95% CI; 39-47%). Multiple procedures and/or the use of anti-arrhythmic drugs increase success to 69% (95% CI; 66-71%). Meta-regression revealed that ablation technique (P < 0.001) and left atrial size (P = 0.02) were predictive of single procedure, drug-free success. The addition of extra-pulmonary substrate approaches was associated with declining efficacy when compared to a pulmonary vein ablation alone., Conclusion: The efficacy of a single-AF ablation procedure for P or LsP AF is 43%; however, can be increased to 69% with the use of multiple procedures and/or anti-arrhythmic drugs. Current literature supports the finding that pulmonary vein antrum ablation/isolation is at least equivalently efficacious to other contemporary P-LsP ablation strategies.

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. β-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.

Purpose of Review: Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia in humans, affecting more than 33 million people globally. Its association with complex, resource intensive medical conditions such as stroke, heart failure and dementia have had profound impacts across existing health care structures. The global prevalence of AF has enjoyed significant growth despite significant improvement in our armamentarium for arrhythmia treatment., Recent Findings: Efforts aimed at curtailing the incidence, prevalence, or progression of AF have prompted re-evaluation of traditional frameworks for understanding and managing this debilitating disease. It is in this context that focus has shifted toward lifestyle-associated factors such as obesity, hypertension, sleep apnoea, exercise, alcohol and diet, as mechanistic drivers and putative targets for therapy. Compelling evidence exists for weight loss and management of associated risk factors to improve outcomes of AF treatment. This review will address the epidemiologic and mechanistic evidence that link lifestyle-associated factors with AF and in light of this analysis evaluate the clinical impacts of their upstream management. Traditional paradigms of AF are shifting in light of emerging evidence, such that risk factor modification has become positioned as the fourth pillar of AF management.

Background An association between atrial fibrillation ( AF ), anxiety, and depression is recognized, but the spectrum of psychological distress remains unclear. We aimed to characterize the severity and predictors of distress associated with AF in a tertiary population and its response to AF management. Methods and Results Seventy-eight patients with symptomatic AF underwent evaluation, including of AF symptom severity, health-related quality of life, psychological distress, suicidal ideation, and specific personality traits. Twenty participants underwent AF ablation and 58 were managed medically, with repeat assessments at 4, 8, and 12 months. Severe distress (Hospital Anxiety and Depression Scale score, ≥15/42) was identified in 27 of 78 (35%). Independent predictors were a personality marked by vulnerability to stress (Perceived Stress Scale: R 2 , 0.54; β=0.7±0.1; t=7.8; P<0.001) and 1 marked by negativity/social inhibition (Type D Personality Scale: R 2 , 0.47; β=0.7±0.1; t=6.7; P<0.001). Suicidal ideation was reported by 16 of 78 (20%) and was predicted by personality traits (Perceived Stress Scale score: R 2 , 0.35; odds ratio, 1.22±0.06; P<0.001; Type D Personality Scale score: R 2 , 0.48; odds ratio, 1.43±0.14; P<0.001). Effective AF ablation (median AF burden 1% [0-1%] over 12 months) was associated with significant reductions in distress (Hospital Anxiety and Depression Scale score, 13.9±1.8 to 4.3±1.8; P<0.05) and prevalence of suicidal ideation (30-5%; P=0.02). Conclusions There was a high prevalence of severe psychological distress (35%) and of suicidal ideation (20%) in a tertiary AF population, with personality traits predicting both. Effective AF ablation was associated with significant improvements, suggesting AF itself may be a treatable causative factor of distress.

Objectives: Recent technology advances have allowed for heart rhythm monitoring using single-lead ECG monitoring devices, which can be used for early diagnosis of atrial fibrillation (AF). We sought to investigate the AF detection rate using portable ECG devices compared with Holter monitoring., Setting, Participants and Outcome Measures: We searched the Medline, Embase and Scopus databases (conducted on 8 May 2017) using search terms related to AF screening and included studies with adults aged >18 years using portable ECG devices or Holter monitoring for AF detection. We excluded studies using implantable loop recorders and pacemakers. Using a random-effects model we calculated the overall AF detection rate. Meta-regression analysis was performed to explore potential sources for heterogeneity. Quality of reporting was assessed using the tool developed by Downs and Black., Results: Portable ECG monitoring was used in 18 studies (n=117 436) and Holter monitoring was used in 36 studies (n=8498). The AF detection rate using portable ECG monitoring was 1.7% (95% CI 1.4 to 2.1), with significant heterogeneity between studies (p<0.001). There was a moderate linear relationship between total monitoring time and AF detection rate (r=0.65, p=0.003), and meta-regression identified total monitoring time (p=0.005) and body mass index (p=0.01) as potential contributors to heterogeneity. The detection rate (4.8%, 95% CI 3.6% to 6.0%) in eight studies (n=10 199), which performed multiple ECG recordings was comparable to that with 24 hours Holter (4.6%, 95% CI 3.5% to 5.7%). Intermittent recordings for 19 min total produced similar AF detection to 24 hours Holter monitoring., Conclusion: Portable ECG devices may offer an efficient screening option for AF compared with 24 hours Holter monitoring., Prospero Registration Number: CRD42017061021., Competing Interests: Competing interests: SR receives equipment and software support from Semacare, a manufacturer of handheld ECG devices. Receives research scholarships from the Heart Foundation and Avant. THM receives equipment and software support from Semacare., (© Author(s) (or their employer(s)) 2018. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Atrial fibrillation (AF) is a recognised arrhythmic risk of endurance sports participation, predominantly affecting middle-aged men who are lifelong athletes. Affected athletes were historically included in the category of lone AF, although specific pathophysiological processes apply to this condition, referred to as exercise-related AF. Younger non-endurance athletes may also present with AF, particularly when associated with co-existing cardiomyopathy or arrhythmia syndrome. Management of exercise-related AF is largely based on evidence from randomised trials in non-athletes. Cornerstones of treatment are, thus, thromboembolic risk reduction and risk factor modification. Rhythm control is generally preferred over rate control due to frequent presentation with symptomatic AF during the paroxysmal phase. Many therapies specific to athletes are based on expert consensus alongside observational data in athletic populations. These include: recommendations to detrain; treatment of symptomatic oesophageal reflux; and preferential use of anticholinergic antidysrhythmic agents to address the predominance of "vagal" AF in athletes. Ongoing research involving cardiac ion channel remodelling and systemic inflammation as mediators of AF genesis may provide future novel therapeutic targets for exercise-related AF. Ablative therapy shows promise in the athletic population with AF, although evidence remains limited. International consensus guidance for disqualification from competitive sports exists to guide medical management alongside athletes' preferences to continue to participate. This review focusses on isolated exercise-related AF and reviews the evidence supporting postulated management recommendations of this unique patient population., (Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Introduction: Cardiac magnetic resonance (CMR)-identified late gadolinium enhancement (LGE), representing regional fibrosis, is often used to predict ventricular arrhythmia risk in nonischemic cardiomyopathy (NICM). However, LGE is more closely correlated with sustained monomorphic ventricular tachycardia (SMVT) than ventricular fibrillation (VF). We characterized CMR findings of ventricular LGE in VF survivors., Methods: We examined consecutively resuscitated VF survivors undergoing contrast-enhanced 1.5T CMR between 9/2007 and 7/2016. We excluded coronary artery disease, hypertrophic cardiomyopathy, amyloid, sarcoid, arrhythmogenic right ventricular cardiomyopathy, and channelopathy. Preexisting implantable cardioverter-defibrillator (ICD) was a CMR contraindication. VF patients were divided into three groups: (1) NICM, (2) left ventricular (LV) dilatation with normal LV ejection fraction (LVEF), and (3) normal LV size and LVEF. Two groups of NICM patients with and without SMVT were examined for comparison., Results: We analyzed 87 VF patients, and found that LGE was seen in 8/22 (36%) with NICM (LVEF 38 ± 11%, LV end-diastolic volume index [LVEDVI] 134 ± 68 mL/BSA), 11/40 (28%) with LV dilatation and normal LVEF (LVEDVI 103 ± 17 mL/BSA), 4/25 (16%) with normal LV size and LVEF. Incidence of LGE in NICM patients without prior ventricular tachycardia/VF (LVEF 36 ± 12%, LVEDVI 141 ± 46 mL/body surface area [BSA]) was 117/277 and was not lower than those with VF and NICM (42% vs 36%; P = 0.59). By contrast, 22/37 NICM patients with SMVT (LVEF 42 ± 11%, LVEDVI 123 ± 48 mL/BSA) were LGE-positive (59% NICM-SMVT vs 36% NICM-VF; P = 0.04)., Conclusion: Most VF survivors with a diagnosis of NICM did not have LGE on CMR and would not have met primary prevention ICD criteria based on LVEF. Absence of LGE may not portend a benign prognosis in NICM. Novel strategies for determining SCD risk in this cohort are required., (© 2018 Wiley Periodicals, Inc.)

Objectives: This study sought to determine if diffuse ventricular fibrosis improves in patients with atrial fibrillation (AF)-mediated cardiomyopathy following the restoration of sinus rhythm., Background: AF coexists in 30% of heart failure (HF) patients and may be an underrecognized reversible cause of left ventricular systolic dysfunction. Myocardial fibrosis is the hallmark of adverse cardiac remodeling in HF, yet its reversibility is unclear., Methods: Patients with persistent AF and an idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%) were randomized to catheter ablation (CA) or ongoing medical rate control as a pre-specified substudy of the CAMERA-MRI (Catheter Ablation versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction-an MRI-Guided Multi-centre Randomised Controlled Trial) trial. All patients had cardiac magnetic resonance imaging scans (including myocardial T1 time), serum B-type natriuretic peptide, 6-min walk tests, and Short Form-36 questionnaires performed at baseline and 6 months. Sixteen patients with no history of AF or left ventricular systolic dysfunction were enrolled as normal controls for T1 time., Results: Thirty-six patients (18 in each treatment arm) were included in this substudy. Demographics, comorbidities, and myocardial T1 times were well matched at baseline. At 6 months, patients in the CA group had a significant reduction in myocardial T1 time from baseline compared with the medical rate control group (-124 ms; 95% confidence interval [CI]: -23 to -225 ms; p = 0.0176), although it remained higher than that of normal controls at 6 months (p = 0.0017). Improvements in myocardial T1 time with CA were associated with significant improvements in absolute LVEF (+12.5%; 95% CI: 5.9% to 19.0%; p = 0.0004), left ventricular end-systolic volume (p = 0.0019), and serum B-type natriuretic peptide (-216 ng/l; 95% CI: -23 to -225 ng/l; p = 0.0125)., Conclusions: The improvement in LVEF and reverse ventricular remodeling following successful CA of AF-mediated cardiomyopathy is accompanied by a regression of diffuse fibrosis. This suggests timely treatment of arrhythmia-mediated cardiomyopathy may minimize irreversible ventricular remodeling., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Despite technological advances, studies continue to report high complication rates for atrial fibrillation (AF) ablation. We sought to review complication rates for AF ablation at a high-volume centre over a 14-year period and identify predictors of complications., Methods: We reviewed prospectively collected data from 2750 consecutive AF ablation procedures at our institution using radiofrequency energy (RF) between January 2004 and May 2017. All cases were performed under general anaesthetic with transoesophageal echocardiography (TEE), 3D-mapping and an irrigated ablation catheter. Double transseptal puncture was performed under TEE guidance. All patients underwent wide antral circumferential isolation of the pulmonary veins (30W anteriorly, 25W posteriorly) with substrate modification at operator discretion., Results: Of 2255 initial and 495 redo procedures, ablation strategies were: pulmonary vein isolation (PVI) only 2097 (76.3%), PVI+ LA lines 368 (13.4%), PVI+posterior wall 191 (6.9%), PVI+cavotricuspid isthmus 277 (10.1%). There were 23 major (0.84%) and 20 minor (0.73%) complications. Cardiac tamponade (five cases - 0.18%) and phrenic nerve palsy (one case - 0.04%) rates were very low. Major vascular complications necessitating surgery or blood transfusion occurred in five patients (0.18%). There were no cases of death, permanent disability, atrio-oesophageal fistulae or symptomatic pulmonary vein (PV) stenosis, although there were five TEE probe-related complications (0.18%). Female gender (OR 2.14; 95% CI 1.07-4.26) but not age >70 (OR 1.01) was the only multivariate predictor of complications., Conclusions: Atrial fibrillation ablation performed at a high-volume centre using RF can be achieved with a low major complication rate in a representative AF population over a sustained period of time., (Copyright © 2018 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

Aims: Rotor mapping and ablation have gained favour over the recent years as an emerging ablation strategy targeting drivers of atrial fibrillation (AF). Their efficacy, however, has been a topic of great debate with variable outcomes across centres. The aim of this study was to systematically review the recent medical literature to determine the medium-term outcomes of rotor ablation in patients with paroxysmal atrial fibrillation (PAF) and persistent atrial fibrillation (PeAF)., Methods and Results: A systematic search of the contemporary scientific literature (PubMed and EMBASE) was performed in August 2017. Only studies assessing arrhythmia-free survival from rotor ablation of AF were included. We used the random-effects model to assess the primary outcome of pooled medium-term single-procedure AF-free survival for both PAF and PeAF. Success rates from multiple procedures and complication rates were also examined. We included 11 observational studies (4 PAF and 10 PeAF) with a total of 556 patients (166 PAF and 390 PeAF). Pooled single-procedure freedom from AF was 37.8% [95% confidence interval 5.6-86.3%] at a mean follow-up period of 13.8 ± 1.8 months for PAF and 59.2% (95% CI 41.4-74.9%) at a mean follow-up period of 12.9 ± 6 months for PeAF. There was a marked heterogeneity between studies (I2 = 93.8% for PAF and 88.3% for PeAF). The mean complication rate of rotor ablation among the reported studies was 3.4%., Conclusion: The wide variability in success rate between different centres performing rotor ablations suggests that the optimal ablation strategy, particularly targeting rotors, is unclear. Results from randomized studies are necessary before this technique can be considered as an established clinical tool.

Background: Pulmonary vein (PV) isolation (PVI) remains the cornerstone of catheter ablation (CA) in persistent atrial fibrillation (AF) (PeAF), although less successful than for paroxysmal AF. Whether rapid or fibrillatory (PV AF) PV firing may identify patients with PeAF more likely to benefit from a PV-based ablation approach is unclear., Objective: The purpose of this study was to determine the relationship between the PV cycle length (PVCL) and the PV AF outcome after CA., Methods: Before ablation, the multipolar catheter was placed in each PV and the left atrial appendage (LAA) for 100 consecutive cycles. The presence of PV AF, the average PVCL of all 4 veins (PV 4VAverage ), the fastest vein average (PV FVAverage ), the fastest cycle length (PV Fast ) both individually and relative to the average LAA cycle length were calculated. The ablation strategy included PVI and posterior wall isolation with a minimum of 12 months follow-up., Results: A total of 123 patients underwent CA (age 62 ± 9.1 years; CHA 2 DS 2 -VASC score 1.6 ± 1.1; left ventricular ejection fraction 48% ± 13%; left atrial area 31 ± 8.7 cm 2 ; AF duration 16 ± 17 months). PVI was achieved in 100% of patients. Multiprocedure success (MPS; freedom from AF/atrial tachycardia episodes lasting >30 seconds) was achieved in 76% of patients at 24 ± 8.1 months of follow-up after 1.2 ± 0.4 procedures. PV activity was not associated with MPS either absolutely (PV 4VAverage [MPS no vs yes: 178 ± 27 ms vs 177 ± 24 ms; P = .92], PV FVAverage [P = .69], or PV Fast [P = .82]) or as a ratio relative to the LAA cycle length (PV 4VAverage /LAA 1.05 ± 0.11 vs 1.06 ± 0.21; P = .87). The presence of PV AF (31% vs 47%; P = .13) did not predict MPS., Conclusion: The rapidity of PV firing or presence of fibrillation within the PV was not predictive of outcome of CA for PeAF. PV activity does not identify patients most likely to benefit from a PV-based ablation strategy., (Copyright © 2018 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Background: Among the growing numbers of patients with heart failure, up to one half have heart failure with preserved ejection fraction (HFpEF). The lack of effective treatments for HFpEF is a substantial and escalating unmet clinical need-and the lack of HFpEF-specific animal models represents a major preclinical barrier in advancing understanding of HFpEF. As established treatments for heart failure with reduced ejection fraction (HFrEF) have proven ineffective for HFpEF, the contention that the intrinsic cardiomyocyte phenotype is distinct in these 2 conditions requires consideration. Our goal was to validate and characterize a new rodent model of HFpEF, undertaking longitudinal investigations to delineate the associated cardiac and cardiomyocyte pathophysiology., Methods and Results: The selectively inbred Hypertrophic Heart Rat (HHR) strain exhibits adult cardiac enlargement (without hypertension) and premature death (40% mortality at 50 weeks) compared to its control strain, the normal heart rat. Hypertrophy was characterized in vivo by maintained systolic parameters (ejection fraction at 85%-90% control) with marked diastolic dysfunction (increased E/E'). Surprisingly, HHR cardiomyocytes were hypercontractile, exhibiting high Ca 2+ operational levels and markedly increased L-type Ca 2+ channel current. In HHR, prominent regions of reparative fibrosis in the left ventricle free wall adjacent to the interventricular septum were observed., Conclusions: Thus, the cardiomyocyte remodeling process in the etiology of this HFpEF model contrasts dramatically with the suppressed Ca 2+ cycling state that typifies heart failure with reduced ejection fraction. These findings may explain clinical observations, that treatments considered appropriate for heart failure with reduced ejection fraction are of little benefit for HFpEF-and suggest a basis for new therapeutic strategies., (© 2018 The Authors. Published on behalf of the American Heart Association, Inc., by Wiley.)

Importance: Obstructive sleep apnea (OSA) is the most common clinically significant breathing abnormality during sleep. It is highly prevalent among patients with atrial fibrillation (AF), and it promotes arrhythmogenesis and impairs treatment efficacy., Observations: The prevalence of OSA ranges from 3% to 49% in population-based studies and from 21% to 74% in patients with AF. Diagnosis and treatment of OSA in patients with AF requires a close interdisciplinary collaboration between electrophysiologists, cardiologists, and sleep specialists. Because the prevalence of OSA is high in patients with AF and most do not report daytime sleepiness, sleep-study evaluation may be reasonable for patients being considered for rhythm control strategy. Acute, transient apnea-associated atrial electrophysiological changes and increased occurrence of AF triggers associated with short episodes of intermittent deoxygenation and reoxygenation, intrathoracic pressure changes during obstructed breathing efforts, and sympathovagal activation combine to create a stimulus for AF triggers and a complex and dynamic substrate for AF during sleep. Repeated episodes of long-term OSA are eventually associated with structural remodeling and changes in electrical conduction in the atrium. Observational data suggest OSA reduces the efficacy of catheter-based and pharmacological antiarrhythmic therapy. Nonrandomized studies have shown that treatment of OSA by continuous positive airway pressure can help to maintain a sinus rhythm after electrical cardioversion and catheter ablation in patients with AF. However, it remains unclear which sleep apnea metric should be used to determine severity and guide such treatment in patients with AF., Conclusions and Relevance: Data from nonrandomized studies of patients with AF suggest that treatment of OSA by continuous positive airway pressure may help to maintain sinus rhythm after electrical cardioversion and improve catheter ablation success rates. Randomized clinical trials are needed to confirm the association between OSA and AF the benefits of treatment of OSA and the need for and cost-effectiveness of routine OSA screening and treatment.

Aims: To determine stroke risk in subclinical atrial fibrillation (AF) and temporal association between subclinical AF and stroke., Methods and Results: Pubmed/Embase was searched for studies reporting stroke in subclinical AF in patients with cardiac implantable electronic devices (CIEDs). After exclusions, 11 studies were analysed. Of these seven studies reported prevalence of subclinical AF, two studies reported association between subclinical and clinical AF, seven studies reported stroke risk in subclinical AF, and five studies reported temporal relationship between subclinical AF and stroke. Subclinical AF was noted after CIEDs implant in 35% [interquartile range (IQR) 34-42] of unselected patients with pacing indication over 1-2.5 years. The definition and cut-off duration (for stroke risk) of subclinical AF varied across studies. Subclinical AF was strongly associated with clinical AF (OR 5.7, 95% CI 4.0-8.0, P < 0.001, I2 = 0%). The annual stroke rate in patients with subclinical AF > defined cut-off duration was 1.89/100 person-year (95% CI 1.02-3.52) with 2.4-fold (95% CI 1.8-3.3, P < 0.001, I2 = 0%) increased risk of stroke as compared to patients with subclinical AF < cut-off duration (absolute risk was 0.93/100 person-year). Three studies provided mean CHADS2 score. In these studies, with mean CHADS2 score of 2.1 ± 0.1, subclinical AF was associated with annual stroke rate of 2.76/100 person-years (95% CI 1.46-5.23). After excluding patients without AF, only 17% strokes occurred in presence of ongoing AF. Subclinical AF was noted in 29% [IQR 8-57] within 30 days preceding stroke., Conclusion: Subclinical AF strongly predicts clinical AF and is associated with elevated absolute stroke risk albeit lower than risk described for clinical AF.

The interaction between arrhythmia episodes and certain lifestyle factors such as obesity and alcohol is well established. There is significant public and professional interest in the role of caffeinated beverages such as coffee, tea, and energy drinks in cardiovascular health. However, many widely held beliefs are not supported by evidence. This study provides a comprehensive review of the impact of caffeinated beverages on cardiac rhythm., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: Current phase mapping systems for atrial fibrillation create 2-dimensional (2D) maps. This process may affect the accurate detection of rotors. We developed a 3-dimensional (3D) phase mapping technique that uses the 3D locations of basket electrodes to project phase onto patient-specific left atrial 3D surface anatomy., Objective: We sought to determine whether rotors detected in 2D phase maps were present at the corresponding time segments and anatomical locations in 3D phase maps., Methods: One-minute left atrial atrial fibrillation recordings were obtained in 14 patients using the basket catheter and analyzed off-line. Using the same phase values, 2D and 3D phase maps were created. Analysis involved determining the dominant propagation patterns in 2D phase maps and evaluating the presence of rotors detected in 2D phase maps in the corresponding 3D phase maps., Results: Using 2D phase mapping, the dominant propagation pattern was single wavefront (36.6%) followed by focal activation (34.0%), disorganized activity (23.7%), rotors (3.3%), and multiple wavefronts (2.4%). Ten transient rotors were observed in 9 of 14 patients (64%). The mean rotor duration was 1.1 ± 0.7 seconds. None of the 10 rotors observed in 2D phase maps were seen at the corresponding time segments and anatomical locations in 3D phase maps; 4 of 10 corresponded with single wavefronts in 3D phase maps, 2 of 10 with 2 simultaneous wavefronts, 1 of 10 with disorganized activity, and in 3 of 10 there was no coverage by the basket catheter at the corresponding 3D anatomical location., Conclusion: Rotors detected in 2D phase maps were not observed in the corresponding 3D phase maps. These findings may have implications for current systems that use 2D phase mapping., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to validate a 3-dimensional (3D) phase mapping system and determine the distribution of dominant propagation patterns in persistent atrial fibrillation (AF)., Background: Currently available systems display phase as simplified 2-dimensional maps. We developed a novel 3D phase mapping system that uses the 3D location of basket catheter electrodes and the patient's 3D left atrial surface geometry to interpolate phase and create a 3D representation of phase progression., Methods: Six-min AF recordings from the left atrium were obtained in 14 patients using the Constellation basket catheter and analyzed offline. Exported signals underwent both phase and traditional activation analysis and were then visualized using a novel 3D mapping system. Analysis involved: 1) validation of phase analysis by comparing beat-to-beat AF cycle length calculated using phase inversion with that determined from activation timing in the same 20-s segment; 2) validation of 3D phase by comparing propagation patterns observed using 3D phase with 3D activation in the same 1-min segment; and 3) determining the distribution of dominant propagation patterns in 6-min recordings using 3D phase., Results: There was strong agreement of beat-to-beat AF cycle length between activation analysis and phase inversion (R 2  = 0.91). There was no significant difference between 3D activation and 3D phase in mean percentage of propagation patterns classified as single wavefronts (p = 0.99), focal activations (p = 0.26), disorganized activity (p = 0.76), or multiple wavefronts (p = 0.70). During prolonged 3D phase, single wavefronts were the most common propagation pattern (50.2%). A total of 34 rotors were seen in 9 of 14 patients. All rotors were transient with mean duration of 1.0 ± 0.6 s. Rotors were only observed in areas of high electrode density where the interelectrode distance was significantly shorter than nonrotor sites (7.4 [interquartile range: 6.3 to 14.6] vs. 15.3 mm [interquartile range: 10.1 to 22.2]; p < 0.001)., Conclusions: During prolonged 3D phase mapping, transient rotors were observed in 64% of patients and reformed at the same anatomic location in 44% of patients. The electrode density of the basket catheter may limit the detection of rotors., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Objectives: This study sought to characterize the biatrial substrate in heart failure (HF) and persistent atrial fibrillation (PeAF)., Background: Atrial fibrillation (AF) and HF frequently coexist; however, the contribution of HF to the biatrial substrate in PeAF is unclear., Methods: Consecutive patients with PeAF and normal left ventricular (NLV) systolic function (left ventricular ejection fraction [LVEF] >55%) or idiopathic cardiomyopathy (LVEF ≤45%) undergoing AF ablation were enrolled. In AF, pulmonary vein (PV) cycle length (PVCL) was recorded via a multipolar catheter in each PV and in the left atrial appendage for 100 consecutive cycles. After electrical cardioversion, biatrial electroanatomic mapping was performed. Complex electrograms, voltage, scarring, and conduction velocity were assessed., Results: Forty patients, 20 patients with HF (mean age: 62 ± 8.9 years; AF duration: 15 ± 11 months; LVEF: 33 ± 8.4%) and 20 with NLV (mean age: 59 ± 6.7 years; AF duration: 14 ± 9.1 months; p = 0.69; mean LVEF: 61 ± 3.6%; p < 0.001), were enrolled. HF reduced biatrial tissue voltage (p < 0.001) with greater voltage heterogeneity (p < 0.001). HF was associated with significantly more biatrial fractionation (left atrium [LA]: 30% vs. 9%; p < 0.001; right atrium [RA]: 28% vs. 11%; p < 0.001), low voltage (<0.5 mV) (LA: 23% vs. 6%; p = 0.002; RA: 20% vs 11%; p = 0.006), and scarring (<0.05 mV) in the LA (p = 0.005). HF was associated with a slower average PVCL (185 vs. 164 ms; p = 0.016), which correlated significantly with PV antral bipolar voltage (R = -0.62; p < 0.001) and fractionation (R = 0.46; p = 0.001)., Conclusions: HF is associated with significantly reduced biatrial tissue voltage, fractionation, and prolongation of PVCL. Advanced biatrial remodeling may have implications for invasive and noninvasive rhythm control strategies in patients with AF and HF., (Copyright © 2018 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Aims: Catheter ablation to achieve posterior left atrial wall (PW) isolation may be performed as an adjunct to pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (AF). We aimed to determine whether routine adenosine challenge for dormant posterior wall conduction improved long-term outcome., Methods and Results: A total of 161 patients with persistent AF (mean age 59 ± 9 years, AF duration 6 ± 5 years) underwent catheter ablation involving circumferential PVI followed by PW isolation. Posterior left atrial wall isolation was performed with a roof and inferior wall line with the endpoint of bidirectional block. In 54 patients, adenosine 15 mg was sequentially administered to assess reconnection of the pulmonary veins and PW. Sites of transient reconnection were ablated and adenosine was repeated until no further reconnection was present. Holter monitoring was performed at 6 and 12 months to assess for arrhythmia recurrence. Posterior left atrial wall isolation was successfully achieved in 91% of 161 patients (procedure duration 191 ± 49 min, mean RF time 40 ± 19 min). Adenosine-induced reconnection of the PW was demonstrated in 17%. The single procedure freedom from recurrent atrial arrhythmia was superior in the adenosine challenge group (65%) vs. no adenosine challenge (40%, P < 0.01) at a mean follow-up of 19 ± 8 months. After multiple procedures, there was significantly improved freedom from AF between patients with vs. without adenosine PW challenge (85 vs. 65%, P = 0.01)., Conclusion: Posterior left atrial wall isolation in addition to PVI is a readily achievable ablation strategy in patients with persistent AF. Routine adenosine challenge for dormant posterior wall conduction was associated with an improvement in the success of catheter ablation for persistent AF., (Published on behalf of the European Society of Cardiology. All rights reserved. © The Author 2017. For permissions please email: journals.permissions@oup.com.)

Atrial fibrillation (AF) is the most common sustained arrhythmia and across the developed nations, it contributes to increasing hospitalizations and healthcare burden. Several comorbidities and risk factors including hypertension, heart failure, obstructive sleep apnoea and obesity are known to play an important role in the initiation and perpetuation of AF and atrial stretch or dilatation may play a central mechanistic role. The impact of atrial stretch in the development of AF can vary dependent on the underlying disease. This review focuses on understanding the substrate for AF in conditions of acute and chronic stretch and in the presence of common co-morbidities or risk factors through the review of findings in both animal and human studies. Additionally, the reversibility of atrial remodeling following stretch release will also be discussed. Identification of clinical conditions associated with increased atrial stretch as well as the treatment or prevention of these conditions may help to prevent AF progression and improve sinus rhythm maintenance., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Background: Atrial fibrillation (AF) and left ventricular systolic dysfunction (LVSD) frequently co-exist despite adequate rate control. Existing randomized studies of AF and LVSD of varying etiologies have reported modest benefits with a rhythm control strategy., Objectives: The goal of this study was to determine whether catheter ablation (CA) for AF could improve LVSD compared with medical rate control (MRC) where the etiology of the LVSD was unexplained, apart from the presence of AF., Methods: This multicenter, randomized clinical trial enrolled patients with persistent AF and idiopathic cardiomyopathy (left ventricular ejection fraction [LVEF] ≤45%). After optimization of rate control, patients underwent cardiac magnetic resonance (CMR) to assess LVEF and late gadolinium enhancement, indicative of ventricular fibrosis, before randomization to either CA or ongoing MRC. CA included pulmonary vein isolation and posterior wall isolation. AF burden post-CA was assessed by using an implanted loop recorder, and adequacy of MRC was assessed by using serial Holter monitoring. The primary endpoint was change in LVEF on repeat CMR at 6 months., Results: A total of 301 patients were screened; 68 patients were enrolled between November 2013 and October 2016 and randomized with 33 in each arm (accounting for 2 dropouts). The average AF burden post-CA was 1.6 ± 5.0% at 6 months. In the intention-to-treat analysis, absolute LVEF improved by 18 ± 13% in the CA group compared with 4.4 ± 13% in the MRC group (p < 0.0001) and normalized (LVEF ≥50%) in 58% versus 9% (p = 0.0002). In those undergoing CA, the absence of late gadolinium enhancement predicted greater improvements in absolute LVEF (10.7%; p = 0.0069) and normalization at 6 months (73% vs. 29%; p = 0.0093)., Conclusions: AF is an underappreciated reversible cause of LVSD in this population despite adequate rate control. The restoration of sinus rhythm with CA results in significant improvements in ventricular function, particularly in the absence of ventricular fibrosis on CMR. This outcome challenges the current treatment paradigm that rate control is the appropriate strategy in patients with AF and LVSD. (Catheter Ablation Versus Medical Rate Control in Atrial Fibrillation and Systolic Dysfunction [CAMERA-MRI]; ACTRN12613000880741)., (Copyright © 2017 American College of Cardiology Foundation. Published by Elsevier Inc. All rights reserved.)

Background: With the recent advent of high-density (HD) 3-dimensional (3D) mapping, the utility of entrainment is uncertain. However, the limitations of visual representation and interpretation of these high-resolution 3D maps are unclear., Objective: The purpose of this study was to determine the strengths and limitations of both HD 3D mapping and entrainment mapping during mapping of right atrial macroreentry., Methods: Fifteen patients were studied. The number and type of circuits accounting for ≥90% of the tachycardia cycle length using HD 3D mapping were verified using systematic entrainment mapping. Entrainment sites with an unexpectedly long postpacing interval despite proximity to the active circuit were evaluated., Results: Based on HD 3D mapping, 27 circuits were observed: 12 peritricuspid, 2 upper loop reentry, 10 lower loop reentry, and 3 lateral wall circuits. With entrainment, 17 of the 27 circuits were active: all 12 peritricuspid and 2 upper loop reentry. However, lower loop reentry was confirmed in only 3 of 10, and none of the 3 lateral wall circuits were present. Mean percentage of tachycardia cycle length covered by active circuits was 98% ± 1% vs 97% ± 2% for passive circuits (P = .09). None of the 345 entrainment runs terminated tachycardia or changed tachycardia mechanism. In 8 of 15 patients, 13 examples of unexpectedly long postpacing interval were observed at entrainment sites located distal to localized zones of slow conduction seen on HD 3D mapping., Conclusion: Using HD 3D mapping, "visual reentry" may be due to passive circuitous propagation rather than a critical reentrant circuit. HD 3D mapping provides new insights into regional conduction and helps explain unusual entrainment phenomena., (Copyright © 2017 Heart Rhythm Society. Published by Elsevier Inc. All rights reserved.)

A correlation exists between the extent of pericardial adipose and atrial fibrillation (AF) risk, though the underlying mechanisms remain unclear. Selected adipose depots express high levels of aromatase, capable of converting androgens to estrogens - no studies have investigated aromatase occurrence/expression regulation in pericardial adipose. The Women's Health Initiative reported that estrogen-only therapy in women elevated AF incidence, indicating augmented estrogenic influence may exacerbate cardiac vulnerability. The aim of this study was to identify the occurrence of pericardial adipose aromatase, evaluate the age- and sex-dependency of local cardiac steroid synthesis capacity and seek preliminary experimental evidence of a link between pericardial adipose aromatase capacity and arrhythmogenic vulnerability. Both human atrial appendage and epicardial adipose exhibited immunoblot aromatase expression. In rodents, myocardium and pericardial adipose aromatase expression increased >20-fold relative to young controls. Comparing young, aged and aged-high fat diet animals, a significant positive correlation was determined between the total aromatase content of pericardial adipose and the occurrence/duration of triggered atrial arrhythmias. Incidence and duration of arrhythmias were increased in hearts perfused with 17β-estradiol. This study provides novel report of pericardial adipose aromatase expression. We show that aromatase expression is remarkably upregulated with aging, and aromatase estrogen conversion capacity significantly elevated with obesity-related cardiac adiposity. Our studies suggest an association between adiposity, aromatase estrogenic capacity and atrial arrhythmogenicity - additional investigation is required to establish causality. The potential impact of these findings may be considerable, and suggests that focus on local cardiac steroid conversion (rather than systemic levels) may yield translational outcomes., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

Introduction: The right atrium (RA) is readily accessible; however, it is unclear whether changes in the RA are representative of the LA. We performed detailed biatrial electroanatomic mapping to determine the electrophysiological relationship between the atria., Methods and Results: Consecutive patients with persistent AF underwent biatrial electroanatomical mapping with a contact force catheter acquiring points with a CF >10 g prior to ablation. Points were analyzed for tissue voltage, complex electrograms, low voltage (<0.5 mV), scar (<0.05 mV), and conduction velocity (CV). Forty patients (mean age 59 ± 9.2 years, AF duration 12.9 ± 9.2 months, LA area: 28 ± 5.2, RA area: 25 ± 6.4 mm 2 , LVEF: 44 ± 15%) underwent mapping during CS pacing. Bipolar voltage (R = 0.57, P <0.001), unipolar voltage (R = 0.68, P <0.001), low voltage (<0.5 nV) (R = 0.48, P = 0.002), fractionation (R = 0.73, P <0.001), and CV (R = 0.49, P = 0.001) correlated well between atria. There was no difference in global bipolar voltage (LA 1.89 ± 0.77 vs. RA 1.77 ± 0.57 mV, P = 0.57); complex electrograms (LA 20% vs. RA 20%, P = 0.99) or low voltage (LA 15% vs. RA 16%, P = 0.84). Global unipolar voltage was significantly higher in the LA compared to the RA (2.95 ± 1.14 vs. 2.28 ± 0.65 mV, P = 0.002) and CV was significantly slower in the RA compared to the LA (0.93 ± 0.15 m/s vs. 1.01 ± 0.19 m/s, P = 0.001)., Conclusion: AF is associated with remodeling processes affecting both atria. The more accessible RA provides an insight into the biatrial process associated with AF in various disease states without trans-septal access., (© 2017 Wiley Periodicals, Inc.)

Exercise has substantial health benefits with pleomorphic vascular, metabolic, psychological and anti-neoplastic actions resulting in improved quality of life and longevity. Despite these many benefits, numerous studies have shown that endurance athletes are more likely to develop atrial fibrillation (AF) than non-athletes. The type, intensity and amount of sport appears to influence the risk of developing AF. Several endurance sport activities have been shown to increase the risk of developing AF but an excess in AF has not been shown in non-endurance sports. Furthermore, lifetime hours of participation appear to increase the risk of developing AF. Intriguingly, women appear relatively protected and an association between endurance sport and AF has not been clearly demonstrated amongst female endurance athletes. The mechanisms by which endurance sport promotes the development of AF are unclear. There are, however, a number of pathophysiological mechanisms which are known to increase the risk of AF in non-athletes which have correlates in athletes. These include structural remodelling of the left atrium, elevated left atrial pressure, inflammation, myocardial fibrosis, vagal tone, sinus bradycardia and genetic predisposition. In this article, we explore how some of these mechanisms may contribute to the development of AF in endurance athletes., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). Published by Elsevier B.V. All rights reserved.)

The epidemic of atrial fibrillation (AF) is increasingly recognised as a growing health problem worldwide. Although epidemiological studies on AF in the Asia-Pacific region are scarce, given the increasing age and size of populations in this region, the burden of AF is expected to be far greater than in North America and Europe. This is not only due to the growing, ageing population but also an increased incidence of risk factors for AF, such as hypertension, obesity, metabolic syndrome and diabetes, in the Asia-Pacific region. While further, high quality data on such aspects as risk factors, racial disparities and clinical implications is urgently required, there is an immediate need for increased focus on appropriate stroke prophylaxis and risk factor management to minimise the clinical complications and societal burden of AF., (Copyright © 2017 Australian and New Zealand Society of Cardiac and Thoracic Surgeons (ANZSCTS) and the Cardiac Society of Australia and New Zealand (CSANZ). All rights reserved.)

Catheter ablation is now at the forefront of the management of symptomatic atrial fibrillation (AF). Its role in paroxysmal AF is well defined with considerable data supporting its role. Catheter ablation in persistent AF has been less effective and the subject of considerable debate. Mechanistic studies have demonstrated the critical role of pulmonary vein physiology in paroxysmal AF, whereas the mechanisms that sustain persistent AF are not well understood. Additional substrate ablation in persistent AF has not improved long-term outcomes and the use of novel mapping technologies to assess rotor activity remains controversial. This review will focus on the current understanding of the mechanistic basis of paroxysmal and persistent AF, the role of catheter ablation and, recent advances in the management of these complex arrhythmias., (Copyright © 2017. Published by Elsevier B.V.)

Atrial fibrillation (AF) is a leading cause of cardiovascular morbidity and mortality worldwide. Management of AF is a complex process involving: 1) the prevention of thromboembolic complications with anticoagulation; 2) rhythm control; and 3) the detection and treatment of underlying heart disease. However, cardiometabolic risk factors, such as obesity, hypertension, diabetes mellitus, and obstructive sleep apnoea, have been proposed as contributors to the expanding epidemic of atrial fibrillation (AF). Thus, a fourth pillar of AF care would include aggressive targeting of interdependent, modifiable cardiovascular risk factors as part of an integrated care model. Such risk factor management could retard and reverse the pathological processes underlying AF and reduce AF burden., (Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.)

Recent advances in our understanding of the mechanisms underlying atrial fibrillation (AF) have further underscored the complex pathophysiological basis of the arrhythmia. It has become apparent that the current clinical classification of AF does not reflect the severity of the underlying atrial disease. Atrial fibrosis has been identified as the key structural change in different substrates that are responsible for the perpetuation of AF. Three-dimensional electroanatomical mapping and late gadolinium-enhanced magnetic resonance imaging are novel modalities that can be used to facilitate identification and quantitation of atrial fibrosis for improved delineation of the AF substrate. Advances in AF mapping technology using endocardial 'panaromic' basket-type catheter and non-invasive body surface electrodes have facilitated the identification of two major arrhythmic mechanisms of interest, namely rotational ('rotors') and ectopic focal activations ('foci'). Ongoing research on these potential drivers of AF may provide guidance to more mechanistic based therapies to improve outcomes for this complex arrhythmia in the future. Here, we aim to review the differences in AF substrate in those with paroxysmal and more persistent forms of the arrhythmia by evaluating fibrosis, rotors and foci, towards improved AF substrate classification and individualised substrate based therapies., (Copyright © 2017. Published by Elsevier B.V.)