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Background: Anticoagulation can prevent most strokes in individuals with atrial fibrillation (AF); however, many people presenting with stroke and known AF are not anticoagulated. Language barriers and poor health literacy have previously been associated with decreased patient medication adherence. The association between language barriers and initiation of anticoagulation therapy for AF is uncertain. Aims: The aims of this study were to determine whether demographic factors, including non‐English primary language, were (1) associated with not being initiated on anticoagulation for known AF prior to admission with stroke, and (2) associated with non‐adherence to anticoagulation in the setting of known AF prior to admission with stroke. Methods: A multicentre retrospective cohort study was conducted for consecutive individuals admitted to the three South Australian tertiary hospitals with stroke units over a 5‐year period. Results: There were 6829 individuals admitted with stroke. These cases included 5835 ischaemic stroke patients, 1333 of whom had pre‐existing AF. Only 40.0% presenting with ischaemic stroke in the setting of known pre‐existing AF were anticoagulated. When controlling for demographics, socioeconomic status and past medical history (including the components of the CHADS2VASC score and anticoagulation contraindications), having a primary language other than English was associated with a lower likelihood of having been commenced on anticoagulant for known pre‐stroke AF (odds ratio: 0.52, 95% confidence interval: 0.36–0.77, P = 0.001), but was not associated with a differing likelihood of anticoagulation adherence. Conclusions: A significant proportion of patients with stroke have pre‐existing unanticoagulated AF; these rates are substantially higher if the primary language is other than English. Targeted research and interventions to minimise evidence‐treatment gaps in this cohort may significantly reduce stroke burden. [ABSTRACT FROM AUTHOR]

Background: Obesity is associated with an increased risk of developing recurrent atrial fibrillation (AF) after catheter ablation (CA). However, the current data on weight loss interventions show inconsistent results in preventing the recurrence of AF after CA. Methods: We conducted a systematic search in MEDLINE and EMBASE to identify studies that reported the outcome of recurrence of AF after CA in obese patients undergoing weight interventions. The subgroup analysis included: (1) Weight loss versus no weight loss, (2) >10% weight loss versus <10% weight loss, (3) <10% weight loss versus no weight loss, (4) Follow‐up <12 months, and (5) Follow‐up >12 months after CA. Mantel–Haenszel risk ratios with a 95% confidence interval (CI) were calculated using a random effects model and for heterogeneity, I2 statistics were reported. Results: A total of 10 studies (one randomized controlled trial and nine observational studies) comprising 1851 patients were included. The recurrence of AF was numerically reduced in the weight loss group (34.5%) versus no weight loss group (58.2%), but no statistically significant difference was observed (risk ratio [RR] = 0.76; 95% CI: 0.49–1.18, p =.22). However, there was a statistically significant reduction in recurrence of AF with weight loss versus no weight loss at follow‐up >12 months after CA (RR = 0.47; 95% CI: 0.32–0.68, p <.0001). At follow‐up >12 months after CA, both >10% weight loss versus <10% weight loss (RR = 0.49; 95% CI: 0.31–0.80, p =.004) and <10% weight loss versus no weight loss (RR = 0.39; 95% CI: 0.31–0.49, p <.00001) were associated with a statistically significant reduction in recurrent AF. Conclusion: In patients with AF undergoing CA, weight loss is associated with reducing recurrent AF at > 12 months after ablation and these benefits are consistently seen with both >10% and <10% weight loss. The benefits of weight loss in preventing recurrent AF after CA should be examined in larger studies with extended follow‐up duration. [ABSTRACT FROM AUTHOR]

Background and purpose: Whether carotid artery disease could improve stroke risk stratification tools in patients with atrial fibrillation (AF) remains uncertain. This study was undertaken to investigate the risk of ischemic stroke associated with occlusive and nonocclusive carotid atherosclerotic disease in patients with AF in the prospective population‐based Cardiovascular Health Study. Methods: We included participants aged ≥65 years with AF. We used multivariable Cox regression analysis to explore the risk of ischemic stroke associated with the percentage of carotid stenosis, plaque irregularity, echogenicity, and vulnerability (markedly irregular, ulcerated, or hypoechoic plaques). Results: A total of 1398 participants were included (55.2% female, 61.7% aged 65–74 years). The maximum carotid stenosis was <50%, 50%–99%, and 100% in 94.5%, 5%, and 0.5% of participants, respectively. High‐risk plaques based on echogenicity and plaque irregularity were found in 25.6% and 8.9% of participants, respectively. After a median follow‐up of 10.9 years (interquartile range = 7.5–15.6), 298 ischemic strokes were recorded. There was no difference in the incidence of ischemic stroke according to the degree of carotid artery stenosis (p = 0.44), plaque echogenicity (low vs. high risk, p = 0.68), plaque irregularity (low vs. high risk, p = 0.55), and plaque vulnerability (p = 0.86). The CHA₂DS₂‐VASc score was associated with an increased risk of ischemic stroke (adjusted hazard ratio = 1.28, 95% confidence interval = 1.18–1.40, p < 0.001). Both maximum grade of stenosis and plaque vulnerability were not associated with incident ischemic stroke (all p > 0.05). Conclusions: Neither the degree of carotid stenosis nor the presence of vulnerable plaques was associated with incident ischemic stroke in this cohort of individuals with AF. This suggests that carotid disease was probably not a significant contributor to ischemic stroke in this population. [ABSTRACT FROM AUTHOR]

Background: Sudden cardiac death (SCD) during physical exercise is devastating. Aims: To evaluate causes and circumstances of exercise‐related SCD in the young in Australia. Methods: We reviewed the National Coronial Information System database for deaths in Australia relating to cardiovascular disease in cases aged 10–35 years between 2000 and 2016. Cases who had undertaken physical exercise at the time of the event were included. We collected demographics, circumstances of death, type of physical exercise, bystander cardiopulmonary resuscitation (CPR) and automated external defibrillator (AED) use prior to ambulance arrival. Results: Over a 17‐year period, 1925 SCD cases were identified, of which 110 (6%) cases (median age 27 years (interquartile range 21–32 years); 92% male) were related to sports/physical exercise. Thirteen (12%) cases occurred in active athletes. Most common causes were coronary artery disease (CAD; 37%) and sudden arrhythmic death syndrome (SADS; 20%). Among Aboriginal and Torres Strait Islanders (n = 10), all deaths were related to CAD. Australian Rules Football (24%), running/jogging (14%) and soccer (14%) were the most frequent physical exercise activities. Prior symptoms were present in 39% (chest pain 37%, pre‐syncope/syncope 26%). Most (87%) were witnessed, with bystander CPR in 70%. AED use prior to ambulance arrival was 8%. Conclusions: The present study demonstrates the high occurrence of CAD and SADS in SCD in the young related to physical exercise. Aboriginal and Torres Strait Islanders were disproportionately affected by CAD. Although events were commonly witnessed, AED was seldom used prior to ambulance arrival and highlights an important opportunity to improve outcomes in the post‐arrest chain of survival. [ABSTRACT FROM AUTHOR]

Background: Implantable cardioverter defibrillators (ICD) are indicated for primary and secondary prevention of sudden cardiac arrest. Despite enhancements in design and technologies, the ICD lead is the most vulnerable component of the ICD system and failure of ICD leads remains a significant clinical problem. A novel, small‐diameter, lumenless, catheter‐delivered, defibrillator lead was developed with the aim to improve long‐term reliability. Methods and Results: The Lead Evaluation for Defibrillation and Reliability (LEADR) study is a multi‐center, single‐arm, Bayesian, adaptive design, pre‐market interventional pivotal clinical study. Up to 60 study sites from around the world will participate in the study. Patients indicated for a de novo ICD will undergo defibrillation testing at implantation and clinical assessments at baseline, implant, pre‐hospital discharge, 3 months, 6 months, and every 6 months thereafter until official study closure. Patients may be participating for a minimum of 18 months to approximately 3 years. Fracture‐free survival will be evaluated using a Bayesian statistical method that incorporates both virtual patient data (combination of bench testing to failure with in‐vivo use condition data) with clinical patients. The clinical subject sample size will be determined using decision rules for number of subject enrollments and follow‐up time based upon the observed number of fractures at certain time points in the study. The adaptive study design will therefore result in a minimum of 500 and a maximum of 900 patients enrolled. Conclusion: The LEADR Clinical Study was designed to efficiently provide evidence for short‐ and long‐term safety and efficacy of a novel lead design using Bayesian methods including a novel virtual patient approach. [ABSTRACT FROM AUTHOR]

Introduction: Use of a novel magnetic sensor enabled optical contact force ablation catheter has been established to be safe and effective for treatment of symptomatic drug‐refractory paroxysmal atrial fibrillation (AF) but has yet to be demonstrated in the persistent AF (PersAF) population. Methods: PERSIST‐END was a multicenter, prospective, nonrandomized, investigational study designed to demonstrate the safety and effectiveness of TactiCath™ Ablation Catheter, Sensor Enabled™(SE) (TactiCath SE) for use in the treatment of subjects with documented PersAF refractory or intolerant to at least one Class I/III AAD. The ablation strategy included pulmonary vein isolation and additional targets at physician discretion. Follow‐up through 15‐months, including a 3‐month blanking period and 3‐month therapy consolidation period, was performed with cardiac event and Holter monitoring. Primary safety, primary effectiveness, clinical success, and quality of life (QOL) endpoints were analyzed. Results: Of 224 subjects enrolled at 21 investigational sites in the United States and Australia, 223 underwent ablation with the investigational catheter. The primary safety event rate was 3.1% (seven events in seven subjects). The Kaplan–Meier estimate of freedom from AF/atrial flutter/atrial tachycardia recurrence at 15‐months was 61.6% and clinical success at 15 months was 89.8%. Subject QOL significantly improved following ablation as assessed via AFEQT (31.6 point increase, p <.0001) and EQ‐5D‐5L (10.7 point increase, p <.0001) and was met with a 53% reduction in all cause cardiovascular healthcare utilization. Conclusion: The sensor‐enabled force‐sensing catheter is safe and effective for the treatment of drug refractory recurrent symptomatic PersAF, reducing arrhythmia recurrence while improving QOL and healthcare utilization. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to report the real‐world atrial fibrillation (AF) diagnostic yield of the implantable cardiac monitor (ICM) in patients with stroke or transient ischemic attack (TIA), and compare it to patients with an ICM for unexplained syncope. Methods: We used patient data from device clinics across the United States of America with ICM remote monitoring via PaceMate™, implanted for stroke or TIA, and unexplained syncope. Patients with known AF or atrial flutter were excluded. The outcome was AF lasting ≥2 min, adjudicated by International Board of Heart Rhythm Examiners certified cardiac device specialists. Results: We included a total of 2469 patients, 51.1% with stroke or TIA (mean age: 69.7 [SD: 12.2] years, 41.1% female) and 48.9% with syncope (mean age: 67.0 [SD: 17.1] years, 59.4% female). The cumulative AF detection rate in patients with stroke or TIA was 5.5%, 8.9%, and 14.0% at 12, 24, and 36 months, respectively. The median episode duration was 73 (interquartile range: 10–456) min, ranging from 2 min to 40.9 days, with 52.3%, 28.6%, and 4.4% of episodes lasting at least 1, 6, and 24 h, respectively. AF detection was increased by age (adjusted hazard ratio [for every 1‐year increase]: 1.024, 95% confidence interval: 1.008–1.040; p =.003), but was not influenced by sex (p =.089). For comparison, the cumulative detection rate at 12, 24, and 36 months were, respectively, 2.4%, 5.2%, and 7.4% in patients with syncope. Conclusion: Patients with stroke or TIA have a higher rate of AF detection. However, this real‐world study shows significantly lower AF detection rates than what has been previously reported. [ABSTRACT FROM AUTHOR]

Aims: Heart failure patients with mid‐range ejection fraction (HFmrEF) have overlapping clinical features, compared with patients with reduced ejection fraction (HFrEF) and preserved ejection fraction (HFpEF). We aim to perform a meta‐analysis of studies reporting long‐term outcomes in HFmrEF compared with HFrEF and HFpEF. Methods and results: Data from 18 eligible large‐scale studies including 126 239 patients were pooled. Patients with HFmrEF had a lower risk of all‐cause death than those with HFrEF [risk ratio (RR) = 0.92; 95% CI = 0.85–0.98; P < 0.001]. This significant difference was seen in the follow‐up at 1, 2, and 3 years. Patients with HFmrEF had significantly lower risk of cardiovascular (CV) deaths than HFrEF (RR = 0.77; 95% CI = 0.65–0.92; P < 0.001). Subgroup analysis showed that studies recruiting >50% of males had higher risk of deaths with HFrEF (RR = 1.15; 95% CI = 1.04–1.26; P = 0.006). When compared with HFpEF, patients with HFmrEF had comparable risk of all‐cause death (RR = 1.02; 95% CI = 0.96–1.09; P = 0.53). Similarly, there were no differences in the 1, 2, and 3 year deaths; CV and non‐CV deaths were insignificant between HFmrEF and HFpEF. Conclusions: The results of the study support that HFmrEF has better prognosis than HFrEF but similar prognosis when compared with HFpEF. Gender disparity between studies seems to influence the results between HFmrEF and HFrEF. Transition in left ventricular ejection fraction (LVEF), which could not be addressed in the study, may play a decisive role in determining outcomes. PROSPERO review registration number CRD42021277107. [ABSTRACT FROM AUTHOR]

Background: Underrepresentation of females in randomized controlled trials (RCTs) limits generalizability and quality of the evidence guiding treatment of females. This study aimed to measure the sex disparities in participants' recruitment in RCTs of atrial fibrillation (AF) and determine associated factors, and to describe the frequency of outcomes reported by sex. Methods: MEDLINE was searched to identify RCTs of AF published between January 1, 2011, and November 20, 2021, in 12 top‐tier journals. We measured the enrollment of females using the enrollment disparity difference (EDD) which is the difference between the proportion of females in the trial and the proportion of females with AF in the underlying general population (obtained from the Global Burden of Disease). Random‐effects meta‐analyses of the EDD were performed, and multivariable meta‐regression was used to explore factors associated with disparity estimates. We also determined the proportion of trials that included sex‐stratified results. Results: Out of 1133 records screened, 142 trials were included, reporting on a total of 133 532 participants. The random‐effects summary EDD was −0.125 (95% confidence interval [CI] = −0.143 to −0.108), indicating that females were under‐enrolled by 12.5 percentage points. Female enrollment was higher in trials with higher sample size (<250 vs. >750, adjusted odds ratio [aOR] 1.065, 95% CI: 1.008–1.125), higher mean participants' age (aOR: 1.006, 95% CI: 1.002–1.009), and lower in trials conducted in North America compared to Europe (aOR: 0.945, 95% CI: 0.898–0.995). Only 36 trials (25.4%) reported outcomes by sex, and of these 29 (80.6%) performed statistical testing of the sex‐by‐treatment interaction. Conclusion: Females remain substantially less represented in RCTs of AF, and sex‐stratified reporting of primary outcomes is infrequent. These findings call for urgent action to improve sex equity in enrollment and sex‐stratified outcomes' reporting in RCTs of AF. [ABSTRACT FROM AUTHOR]

Background: Long‐term exercise induces cardiac remodeling that potentially influences the electrical properties of the heart. Hypothesis/objectives: We assessed whether training alters cardiac conduction in Standardbred racehorses. Animals: Two hundred one trained and 52 untrained Standardbred horses. Methods: Cross‐sectional study. Resting ECG recordings were analyzed to assess heart rate (HR) along with standard ECG parameters and for identification of atrial and ventricular arrhythmias. An electrophysiological study was performed in 13 horses assessing the effect of training on sinoatrial (SA) and atrioventricular (AV) nodal function by sinus node recovery time (SNRT) and His signal recordings. Age and sex adjustments were implemented in multiple and logistic regression models for comparison. Results: Resting HR in beats per minute (bpm) was lower in trained vs untrained horses (mean, 30.8 ± 2.6 bpm vs 32.9 ± 4.2 bpm; P =.001). Trained horses more often displayed second‐degree atrioventricular block (2AVB; odds ratio, 2.59; P =.04). No difference in SNRT was found between groups (n = 13). Mean P‐A, A‐H, and H‐V intervals were 71 ± 20, 209 ± 41, and 134 ± 41 ms, respectively (n = 7). We did not detect a training effect on AV‐nodal conduction intervals. His signals were present in 1 horse during 2AVB with varying H‐V interval preceding a blocked beat. Conclusions and Clinical Importance: We identified decreased HR and increased frequency of 2AVB in trained horses. In 5 of 7 horses, His signal recordings had variable H‐V intervals within each individual horse, providing novel insight into AV conduction in horses. [ABSTRACT FROM AUTHOR]

Introduction: Although single ring isolation is an accepted strategy for undertaking pulmonary vein (PV) and posterior wall isolation (PWI) during atrial fibrillation (AF) ablation, the learning curve associated with this technique as well as procedural and clinical success rates have not been widely reported. Methods and Results: Prospectively collected data from 250 consecutive patients undergoing de novo AF ablation using single ring isolation. PWI was achieved in 212 patients (84.8%) and PV isolation without PWI was achieved in 37 patients (14.4%). Thirty‐one cases (12.4%) demonstrated inferior line sparing where PWI was achieved without a continuous posterior wall inferior line. A learning curve was observed, with higher rates of PWI (98% last 50 vs. 82% first 50 cases, p =.016), higher rates of inferior line sparing (20% last 50 vs. 8% first 50 cases, p =.071) and lower ablation times (43.8 min (interquartile range [IQR]: 34.6–57.0 min) last 50 versus. 96.5 min (IQR: 80.8–115.8 min) first 50 cases; p <.001). Three (1.3%) major procedure‐related complications were observed. Twelve‐month, single‐procedure freedom from atrial arrhythmia without drugs was 70.5% (95% confidence interval [CI]: 61.5%–77.7%) and 60.0% (95% CI: 50.2%–68.4%) for paroxysmal and persistent/longstanding persistent AF. Twelve‐month multi‐procedure freedom from atrial arrhythmia was 92.2% (95%CI: 85.6%–95.9%) and 85.6% (95%CI: 77.2%–91.0%) for paroxysmal and persistent/longstanding persistent AF. Conclusion: Employing a single ring isolation approach, PWI can be achieved in most cases. There is a substantial learning curve with higher rates of PWI, reduced ablation times, and higher rates of inferior line sparing as procedural experience grows. Long‐term freedom from arrhythmia is comparable to other AF ablation techniques. [ABSTRACT FROM AUTHOR]

Objective: To summarize data on the prevalence/incidence, risk factors and prognosis of atrial fibrillation (AF) in patients with acute coronary syndromes (ACS). Methods: MEDLINE, Embase, and Web of Science were searched to identify all published studies providing relevant data through August 23, 2020. Random‐effects meta‐analysis method was used to pool estimates. Results: We included 109 studies reporting data from a pooled population of 8 239 364 patients. The prevalence rates were 5.8% for pre‐existing AF, 7.3% for newly diagnosed AF, and 11.3% for prevalent (total) AF, in patients with ACS. Predictors of newly diagnosed AF included age (per year increase) (adjusted odds ratio [aOR]: 1.05), C‐reactive protein (aOR: 1.49), left atrial (LA) diameter (aOR: 1.08), LA dilatation (aOR: 2.32), left ventricular ejection fraction <40% (aOR: 1.82), hypertension (aOR: 1.87), and Killip ˃ 1 (aOR: 1.85), p <.01 in all analyzes. Newly diagnosed AF was associated with an increased risk of acute heart failure (adjusted hazard ratio [aHR]: 3.20), acute kidney injury (aHR: 3.09), re‐infarction (aHR: 1.96), stroke (aHR: 2.15), major bleeding (aHR: 2.93), and mortality (aHR: 1.80) in the short term; and with an increased risk of heart failure (aHR: 2.21), stroke (aHR: 1.75), mortality (aHR: 1.67), CV mortality (aHR: 2.09), sudden cardiac death (aHR: 1.53), and a composite of major adverse cardiovascular events (aHR: 1.54) in the long term (beyond 1 month), p <.05 in all analyzes. Conclusion: One in nine patients with ACS has AF, with a high proportion of newly diagnosed AF. AF, in particular newly diagnosed AF, is associated with poor short‐term and long‐term outcomes in patients with ACS. [ABSTRACT FROM AUTHOR]

Background: Limited information is available on paroxysmal atrial fibrillation (PAF) in the horse. Indeed, undiagnosed PAF could result in poor performance. Due to the intermittent occurrence, PAF is difficult to diagnose. However, implanting a small ECG device (implantable loop recorder, ILR) subcutaneously, allows the continuous and automatic detection of PAF. Objectives: The aim was to investigate the potential of ILRs as a tool for diagnosing PAF in horses with poor performance. Study design: Prospective field study. Methods: Twelve racing Standardbred trotters with intermittent reduced performance (mean age: six years) were enrolled prospectively. The ILR was implanted subcutaneously at the fifth or sixth left intercostal space and data from the ILR was collected during the study period in which the horses were followed for a median duration of 7.5 month (range 6‐28). Results: The ILR was able to detect PAF in four out of twelve racehorses. The ILR also detected sustained atrial fibrillation (AF) in one horse during the study. The ILRs rely on RR detection and R waves were correctly identified in 96%. One hundred episodes were categorised as AF by the ILRs and subsequently visual ECG inspection categorised 12 as sinus rhythm (SR), 28 as sinus arrhythmia (SA), 14 as other arrhythmias and 46 as AF episodes. The Root Mean Square of the Successive Differences (RMSSD) values were significantly increased for AF compared to SR and SA. Main limitations: Few horses included and duration of study period varied among the horses. Further it was not possible to assess the sensitivity of the device in the current study and the ILRs proved to have a high rate of false positive misclassifications. Conclusions: This study indicates that ILRs can be used for detection of PAF episodes and could be a useful ECG tool for horses presenting with poor performance. This methodology provides a platform to facilitate the long‐term assessment of AF development and quantification of AF burden in horses. Further studies including both healthy and poor performing horses are needed in order to learn more about PAF prevalence in racehorses. [ABSTRACT FROM AUTHOR]

Background: Ocular coherence tomography angiography (OCTA) is available in varying size and resolution. We sought to characterise associations of cardiometabolic factors with retinal microvascular changes using 3 × 3, 6 × 6 and 8 × 8‐mm OCTA scans to determine differences in detection with varying scan size. Methods: Cross‐sectional study of 247 cardiovascular patients from a single‐centre tertiary‐care hospital. Demographic, comorbidity and medication data were obtained. Patients underwent 3 × 3, 6 × 6 and 8 × 8‐mm macula OCTA scanning using Carl Zeiss CIRRUS HD‐OCT Model 5000. Angioplex and AngioTool software was used to quantify vascular parameters in the superficial capillary plexus. Results: Increasing age, hypertension, dyslipidaemia, diabetes, chronic kidney disease, coronary artery disease and peripheral vascular disease were associated with reductions in vessel density, vessel perfusion, average vessel length and/or junction density in 3 × 3‐mm OCTA (P <.05 for all). Conversely, smoking was associated with increased vessel density, vessel length and junction density in 3 × 3‐mm OCTA (P <.05 for all). Associations of vessel abnormalities with cardiometabolic factors were progressively weakened and statistically attenuated in 6 × 6 and 8 × 8‐mm OCTA scans. In multivariate analyses, dyslipidaemia remained an independent predictor of reduced vessel density, average vessel length and junction density (P <.05). Conclusions: Cardiometabolic factors are associated with multiple retinal microvascular changes in 3 × 3‐mm OCTA scans. These associations were weakened and progressively attenuated in OCTA scans of larger 6 × 6 and 8 × 8‐mm size. These findings advance our understanding of microcirculatory dysfunction and may have future implications for the screening and management of patients with cardiometabolic risk factors. Additional studies are required to further investigate these important associations. [ABSTRACT FROM AUTHOR]

Introduction: Success rates of catheter ablation in persistent atrial fibrillation (AF) remain suboptimal. A better and more targeted ablation strategy is urgently needed to optimize outcomes of AF treatment. We sought to assess the safety and efficacy of targeting atrial fibrosis during ablation of persistent AF patients in improving procedural outcomes. Methods: The DECAAF II trial (ClinicalTrials. gov identifier number NCT02529319) is a prospective, randomized, multicenter trial of patients with persistent AF. Patients with persistent AF undergoing a first‐time ablation procedure were randomized in a 1:1 fashion to receive conventional pulmonary vein isolation (PVI) ablation (Group 1) or PVI + fibrosis‐guided ablation (Group 2). Left atrial fibrosis and ablation induced scarring were defined by late gadolinium enhancement magnetic resonance imaging at baseline and at 3–12 months postablation, respectively. The primary endpoint is the recurrence of atrial arrhythmia postablation, including atrial fibrillation, atrial flutter, or atrial tachycardia after the 90‐day postablation blanking period. Patients were followed for a period of 12–18 months with a smartphone ECG Device (ECG Check Device, Cardiac Designs Inc.). With an anticipated enrollment of 900 patients, this study has an 80% power to detect a 26% reduction in the hazard ratio of the primary endpoint. Results and Conclusion: The DECAAF II trial is the first prospective, randomized, multicenter trial of patients with persistent AF using imaging defined atrial fibrosis as a treatment target. The trial will help define an optimal approach to catheter ablation of persistent AF, further our understanding of influencers of ablation lesion formation, and refine selection criteria for ablation based on atrial myopathy burden. [ABSTRACT FROM AUTHOR]

Background: Anemia frequently coexists with atrial fibrillation (AF) and has been variably associated with worse outcomes. We performed a systematic review and meta‐analysis to comprehensively assess the effect of anemia on mortality, stroke/systemic thromboembolism, and bleeding events in patients with AF. Methods: MEDLINE and Embase were searched from inception until May 2020. Studies examining associations of anemia with the above outcomes in AF patients were included, and maximally adjusted hazard ratios (HRs) meta‐analysed. PROSPERO registration number CRD42020171113. Results: Twenty‐eight studies involving 365 484 patients (41% female, mean age 74.7 years) were included. The average study follow‐up ranged from 0.2 to 4.0 years, and the prevalence of anemia was 16%. Anemia was associated with a 78% increase in all‐cause mortality (HR, 1.78; 95% confidence interval [CI], 1.44–2.20), 60% increase in cardiovascular mortality (HR, 1.60; 95% CI, 1.17–2.19), 134% increase in noncardiovascular mortality (HR, 2.34; 95% CI, 1.58–3.47) 15% increase in stroke/systemic thromboembolism (HR, 1.15; 95% CI, 1.01–1.31), 78% increase in major bleeding (HR, 1.78; 95% CI, 1.54–2.05), and 77% increase in gastrointestinal bleeding (HR, 1.77; 95% CI, 1.23–2.55). Sensitivity analyses including studies that reported odds ratios did not result in any material change. Conclusion: Anemia is a frequently observed comorbidity in patients with AF, and is associated with an increased risk of all‐cause, cardiovascular and noncardiovascular mortality, stroke/systemic thromboembolism, and major and gastrointestinal bleeding. Future studies are required to explore the causes of anemia in AF, and whether investigation and treatment may be clinically beneficial in affected individuals. [ABSTRACT FROM AUTHOR]

Objective: To characterize contemporary pacemaker procedure trends. Methods: Nationwide analysis of pacemaker procedures and costs between 2008 and 2017 in Australia. The main outcome measures were total, age‐ and gender‐specific implant, replacement, and complication rates, and costs. Results: Pacemaker implants increased from 12,153 to 17,862. Implantation rates rose from 55.3 to 72.6 per 100,000, a 2.8% annual increase (incidence rate ratio [IRR] 1.028; 95% CI, 1.02–1.04; p <.001). Pacemaker implants in the 80+ age group were 17.37‐times higher than the < 50 group (95% CI 16.24–18.59; p <.001), and in males were 1.48‐times higher than in females (95% CI 1.42–1.55; p <.001). However, there were similar increases according to age (p =.10) and gender (p =.68) over the study period. Left ventricular lead rates were stable (IRR 0.995; 95% CI 0.98–1.01; p =.53). Generator replacements decreased from 20.5 to 18.3 per 100,000 (IRR 0.975; 95% CI 0.97–0.98; p <.001). Although procedures for generator‐related complications were stable (IRR 0.995; 95% CI 0.98–1.01; p =.54), those for lead‐related complications decreased (IRR 0.985; 95% CI 0.98–0.99; p <.001). Rates for all pacemaker procedures were consistently greater in males (p <.001). Although annual costs of all pacemaker procedures increased from $178 million to $329 million, inflation‐adjusted costs were more stable, rising from $294 million to $329 million. Conclusions: Increasing demand for pacemaker implants is driven by the ageing population and rising rates across all ages, while replacement and complication procedure rates appeared more stable. Males have consistently greater pacemaker procedure rates than females. Our findings have significant clinical and public health implications for healthcare resource planning. [ABSTRACT FROM AUTHOR]

Background: Three‐dimensional electroanatomical mapping is of potential interest in equine cardiology to identify arrhythmia mechanisms, characterise electroanatomical substrates and guide ablation strategies. Objectives: To describe three‐dimensional electroanatomical mapping in standing horses. Study design: Research methodology, proof of concept study. Methods: Four Standardbred horses (2 geldings, 2 mares, median age 4.5 [4‐9] years, mean bodyweight 485 [440‐550] kg) were sedated and placed in stocks. Via the jugular vein, a high‐density multipolar grid catheter (Advisor™ HD Grid Mapping Catheter with EnSite VelocityTM, Abbott Medical) was used for endocardial mapping of the right atrium. The P‐wave on the surface ECG was used as a timing reference for simultaneous local activation time‐ and bipolar voltage‐mapping. For a positional reference a 10‐pole catheter (Abbott Medical) was placed in the caudal vena cava. Results: Endocardial right atrial mapping guided by the three‐dimensional mapping system and local electrograms was successfully performed in all four horses. A median of 32719 [25499‐65078] points, covering the entire right atrium, were collected. Three‐dimensional electroanatomical mapping provided detailed information about activation patterns and electrogram‐characteristics of the sinoatrial node, intervenous tubercle and cavotricuspid isthmus. Additionally, transvenous biopsy forceps connected to the mapping system were visualised on screen to guide biopsy collection. Main limitations: The feasibility of electroanatomical mapping for the left atrium and in larger breeds requires further study. Conclusions: High‐density three‐dimensional electroanatomical mapping of the right atrium is feasible in the standing horse. [ABSTRACT FROM AUTHOR]

Background: Implantable cardioverter defibrillators (ICDs) reduce all‐cause mortality among cardiomyopathy patients. Whether or not antitachycardia pacing (ATP) is equally effective in ischemic (ICM) and nonischemic (NICM) cardiomyopathy patients remains poorly understood. We describe the distribution of monomorphic (MVT) and non‐monomorphic (polymorphic ventricular tachycardia/ventricular fibrillation [PVT/VF]) ventricular tachyarrhythmias among ICM and NICM primary prevention patients. Methods: This patient‐level meta‐analysis included primary prevention patients from the Shock‐Less (n = 3519), PainFree SST (n = 1917), and PREPARE (n = 690) studies. Distribution of MVT and PVT/VF events were compared with χ2 tests. ATP success was estimated using a generalized estimating equation model to correct for multiple episodes for a patient between cohorts for slow (≥320 ms) and fast (240–310 ms) MVTs. Results: Among 6126 patients, 714 (29% NICM, age 66 ± 13 years, female 18%, EF = 29 ± 12%) had a total of 4444 treated ventricular tachyarrhythmia episodes. The rate of individuals treated for MVT or PVT/VF was comparable between ICM (11.9%) and NICM (11.2%) over 21 ± 10 months. In addition, the distribution of MVT (76% ICM vs. 71% NICM) and PVT/VF (15% ICM vs. 20% NICM) was not significantly different (p =.28). Among MVT episodes, the average tachycardia cycle lengths (332 ± 58 ms ICM vs. 313 ± 40 ms NICM; p =.27) were similar, as was the likelihood of ATP‐associated termination (74.6% ICM vs. 76.4% NICM; p =.58). Overall, ATP success was higher for slow (≥320 ms) MVT versus faster (240–310 ms) episodes (84.1% vs. 69%; p <.001). Conclusion: In a large cohort of primary prevention ICD patients, ICM and NICM patients have similar rates and proportions of MVT and PVT/VF episodes. ATP‐associated termination of MVT was comparable between the two groups. [ABSTRACT FROM AUTHOR]

Background: Endocardial pacing may be beneficial in patients who fail to improve following conventional epicardial cardiac resynchronization therapy (CRT). The potential to pace anywhere inside the left ventricle thus avoiding myocardial scar and targeting the latest activating segments may be particularly important. The WiSE‐CRT system (EBR systems, Sunnyvale, CA) reliably produces wireless, endocardial left ventricular (LV) pacing. The purpose of this analysis was to determine whether this system improved symptoms or led to LV remodeling in patients who were nonresponders to conventional CRT. Method: An international, multicenter registry of patients who were nonresponders to conventional CRT and underwent implantation with the WiSE‐CRT system was collected. Results: Twenty‐two patients were included; 20 patients underwent successful implantation with confirmation of endocardial biventricular pacing and in 2 patients, there was a failure of electrode capture. Eighteen patients proceeded to 6‐month follow‐up; endocardial pacing resulted in a significant reduction in QRS duration compared with intrinsic QRS duration (26.6 ± 24.4 ms; P =.002) and improvement in left ventricular ejection fraction (LVEF) (4.7 ± 7.9%; P =.021). The mean reduction in left ventricular end‐diastolic volume was 8.3 ± 42.3 cm3 (P =.458) and left ventricular end‐systolic volume (LVESV) was 13.1 ± 44.3 cm3 (P =.271), which were statistically nonsignificant. Overall, 55.6% of patients had improvement in their clinical composite score and 66.7% had a reduction in LVESV ≥15% and/or absolute improvement in LVEF ≥5%. Conclusion: Nonresponders to conventional CRT have few remaining treatment options. We have shown in this high‐risk patient group that the WiSE‐CRT system results in improvement in their clinical composite scores and leads to LV remodeling. [ABSTRACT FROM AUTHOR]

The article offers information on appraisal of high‐power short‐duration radiofrequency ablation for pulmonary vein isolation. Topics discussed include need for strategy being developed for ablation in the left atrium to accomplish transmural lesions with no collateral tissue damage; information on high‐power short duration (HPSD) radiofrequency (RF) application; and informaton on pulmonary vein isolation (PVI) that remains the cornerstone in any ablation strategy.

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. [ABSTRACT FROM AUTHOR]

The article offers information on gastric autonomic activity and atrial fibrillation (AF) susceptibility in gastroesophageal reflux disease. It mentions information on association between gastroesophageal reflux disease (GERD) and AF; and also mentions about acute electrophysiological changes in atrial refractoriness and associated increased inducibility of AF in an animal model of GERD.

The article offers information on a study related to exercise tolerance with catheter ablation. It mentions that achieving sustained sinus rhythm following catheter ablation among patients with persistent atrial fibrillation (AF) results in clinically relevant improvements in peak oxygen uptake; and also mentions need for understanding on the effects of AF ablation on hemodynamics and atrial function.

Abstract: Introduction: Atrioesophageal fistula (AEF) is a dire complication of atrial fibrillation ablation. The diagnostic yield of computed tomography (CT) chest, the role and timing of repeat testing, and the value of other investigations in the diagnosis of AEF is uncertain. Methods: We systematically reviewed published AEF cases to evaluate radiological, bedside, and biochemical investigations for AEF (registered on PROSPERO [CRD42017077493]). Results: Eighty‐seven articles with 126 patients (median age, 59 years; male, 71%) were included in the analysis. CT chest was performed in 88% (111/126) and was abnormal in 87%. A clear diagnosis of AEF (fistula/perforation) was only detected in 35% (34/97). Other major findings included free air in mediastinum (26%), left atrium (LA), or LA wall (24%). In 11 patients with normal/nonspecific initial CT chest, major abnormalities were detected in 91% (10/11) of repeat CT chest performed 6 days (median; range, 4–22) after initial scan. Initial CT head was normal in 51%; diffuse air emboli was identified in 79% (22/28). Initial transthoracic echocardiography was normal in 61% of cases. The spectrum of radiological abnormalities included Air (mediastinum/LA), Effusion (pleural/pericardial), Fistula/Perforation, and Thickening (esophagus/LA) ‐ “AEF‐Tests.” Esophagram demonstrated contrast extravasation in 87% (13/15). Blood culture was consistently positive (100%; 28/28), particularly for streptococcus species (93%; 26/28). Conclusion: The diagnosis of AEF remains challenging. Clinicians should be aware of the limitations in the yield of CT chest, the variety of major abnormalities reported, the need for repeat testing, unique brain imaging findings, and the importance of positive blood cultures and raised inflammatory markers. [ABSTRACT FROM AUTHOR]

Background Medical technology has made significant advances over the last few decades with smaller and more dynamic pacemakers. However, technical failures leading to premature replacement is a cause of concern. We present a series of Medtronic EnRhythm devices that reached premature elective replacement indicator (ERI). Methods The database of Centre of Heart Rhythm Disorders was searched for EnRhythm device implantation from 2006 to 2011. Battery depletion <8.5 years was considered premature considering the projected average longevity to be 8.5-10.5 years. An unexpected premature ERI was defined when it was reached within 3 months of last normal check. Device follow-up was conducted every 3 months after advisory. Results A total of 88 EnRhythm pacemakers were implanted. Over a median follow-up of 6.2 years (range: 0.3-9.2), 39 (44.3%) EnRhythm devices reached premature ERI. In 11 (28%), ERI was not recognized and patients were being investigated for other causes of unsteadiness or dyspnea prior to device check. Notably, three (7%) patients had premature ERI < 3.5 years. Ten (25.6%) had sudden and unexpected premature ERI. While asynchronous pacing was observed, there were no cases of absence of pacing. Conclusions The rate of premature ERI for EnRhythm devices was 44.3%, significantly higher than reported by the manufacturer. Of concern, a sizeable proportion occurred unexpectedly, warranting more frequent reviews and empirical replacement in some patients. With the experience of the EnRhythm, appropriate monitoring strategies are recommended for future advisories. [ABSTRACT FROM AUTHOR]

Background Sequentially mapped complex fractionated atrial electrograms (CFAE) and dominant frequency (DF) sites have been targeted during catheter ablation for atrial fibrillation (AF). However, these strategies have yielded variable success and have not been shown to correlate consistently with AF dynamics. Here, we evaluated whether the spatiotemporal stability of CFAE and DF may be a better marker of AF sustenance and termination. Methods Eighteen sheep with 12 weeks of “one-kidney, one-clip” hypertension underwent open-chest studies. A total of 42 self-terminating (28–100 s) and 6 sustained (>15 min) AF episodes were mapped using a custom epicardial plaque and analyzed in 4-s epochs for CFAE, using the NavX CFE-m algorithm, and DF, using a Fast Fourier Transform. The spatiotemporal stability index (STSI) was calculated using the intraclass correlation coefficient of consecutive AF epochs. Results A total of 67,733 AF epochs were analyzed. During AF initiation, mean CFE-m and the STSI of CFE-m/DF were similar between sustained and self-terminating episodes, although median DF was higher in sustained AF ( p =0.001). During sustained AF, the STSI of CFE-m increased significantly ( p =0.02), whereas mean CFE-m ( p =0.5), median DF ( p =0.07), and the STSI of DF remained unchanged ( p =0.5). Prior to AF termination, the STSI of CFE-m was significantly lower ( p <0.001), with a physiologically non-significant decrease in median DF (−0.3 Hz, p =0.006) and no significant changes in mean CFE-m ( p =0.14) or the STSI of DF ( p =0.06). Conclusions Spatiotemporal stabilization of CFAE favors AF sustenance and its destabilization heralds AF termination. The STSI of CFE-m is more representative of AF dynamics than are the STSI of DF, sequential mean CFE-m, or median DF. [ABSTRACT FROM AUTHOR]

Obstructive Sleep Apnea Treatment Prevalence rates of atrial fibrillation (AF) and obstructive sleep apnea (OSA) are rising on a global scale. Epidemiological data have consistently demonstrated an independent association between the 2 conditions. Investigators pose that pathophysiologic features of OSA enable progression of the AF substrate; these features include abnormalities of gas exchange, autonomic remodeling, atrial stretch, and inflammation. Furthermore, many of the mechanistic perturbations that impact the AF substrate in OSA can be substantially attenuated by effective treatment with continuous positive airway pressure (CPAP). Clear associations of OSA treatment and improved AF control have been observed across multiple clinical contexts. However, the precision and generalizability of these findings are unclear in view of the data's observational nature. Although risk factor management has emerged as a critical component of AF treatment, effective control of many AF risk factors can be challenging in the longer term. In view of the efficacy and sustainability of CPAP therapy, OSA raises its profile as a prime candidate for intervention. However, translation of this strategy to the broader framework for AF management requires robust data from randomized controlled trials. [ABSTRACT FROM AUTHOR]

Background Atrial fibrillation (AF) is an arrhythmia that can be difficult to identify and classify with short-term monitoring. However, current standard of practice requires only short-term monitoring to determine AF classifications and identify symptom-arrhythmia correlations prior to AF ablation procedures. Insertable cardiac monitors (ICMs) offer continuous arrhythmia monitoring, which could lead to a more accurate measurement of AF burden than standard of practice. Methods This analysis focused on 121 patients enrolled in the LINQ Usability Study indicated for an AF ablation. Patients were followed for up to 1 year after ICM insertion. Clinical AF classifications were made by physicians prior to ICM implantation based on available clinical information. Device-detected AF burden and maximum daily burden were collected from device interrogations and remote transmissions. Device AF classifications were determined by categorizing the AF burden based on guidelines. Results Agreement between clinical and device AF classifications preablation was poor (48.3%, N = 58). The strongest agreement was in the paroxysmal AF group but still was only 61.8%. Furthermore, device-detected preablation AF burden led to the decision to defer AF ablation procedures in 16 (13.2%) patients. The median AF burden in patients with ≥6 months follow-up postablation (n = 71) was reduced from 7.8% (interquartile range [IQR]: 0-32.1%) to 0% (IQR: 0-0.7%). Conclusions ICM monitoring to determine AF burden pre- and post-AF ablation may have clinical utility for management of ablation candidates through more accurate AF classification and guiding treatment decisions. [ABSTRACT FROM AUTHOR]

Hypertrophic cardiomyopathy (HCM) is a common heritable cardiac disorder with diverse clinical outcomes including sudden death, heart failure, and stroke. Depressed heart rate variability (HRV), a measure of cardiac autonomic regulation, has been shown to predict mortality in patients with cardiovascular disease. Cardiac autonomic remodelling in animal models of HCM are not well characterised. This study analysed Gly203- Ser cardiac troponin-I transgenic (TG) male mice previously demonstrated to develop hallmarks of HCM by age 21 weeks. 33 mice aged 30 and 50 weeks underwent continuous electrocardiogram (ECG) recording for 30 min under anaesthesia. TG mice demonstrated prolonged P-wave duration (P < 0.001) and PR intervals (P < 0.001) compared to controls. Additionally, TG mice demonstrated depressed standard deviation of RR intervals (SDRR; P < 0.01), coefficient of variation of RR intervals (CVRR; P < 0.001) and standard deviation of heart rate (SDHR; P < 0.001) compared to controls. Additionally, total power was significantly reduced in TG mice (P < 0.05). No significant age-related difference in either strain was observed in ECG or HRV parameters. Mice with HCM developed slowed atrial and atrioventricular conduction and depressed HRV. These changes were conserved with increasing age. This finding may be indicative of atrial and ventricular hypertrophy or dysfunction, and perhaps an indication of worse clinical outcome in heart failure progression in HCM patients. [ABSTRACT FROM AUTHOR]

Background: Insertable cardiac monitors (ICMs) are used to continuously monitor the patient's electrocardiogram. In response to patient activation or based on automated device algorithms, arrhythmia episodes are stored and automatically transmitted daily to the clinician. Thus, ICMs can be used to diagnose arrhythmias in at-risk patients and in those with symptoms potentially attributable to arrhythmias. The ICM described in this report has undergone a dramatic change in size and method of insertion. Methods: To evaluate the safety profile of the ICM procedure, we analyzed procedure-related adverse events (AEs) from two separate trials: A controlled, nonrandomized multicenter study (Reveal LINQTM Usability study) and a multicenter registry (Reveal LINQTM Registry) evaluating real-world experience. For the Registry we reported all procedure-related AEs upon occurrence, whereas for the Usability study, we reported events occurring during the first month of follow-up. Results: The Usability study enrolled 151 patients (age 56.6 ± 12.1 years; male 67%) at 16 centers; during follow-up, an infection was observed in 1.3% patients and a procedure-related serious AE (SAE) in 0.7% patients. The Registry enrolled 122 patients (age 61.0 ± 17.8 years; male 47%) at seven centers; during follow-up, an infection was observed in 1.6% patients and a procedure-related SAE in 1.6% patients. Conclusions: The cumulative experience from a controlled clinical trial and a "real-world" registry demonstrate that the new ICM can be inserted with very low incidence of AEs. [ABSTRACT FROM AUTHOR]

The article offers a commentary on a study on atrial fibrillation (AF) frequency mapping using continuous wavelet transform (CWT). Topics covered include the need to determine the substrate responsible for AF specific to individual patient for a more targeted ablative therapy, costs associated with mapping techniques using basket-type catheter and non-invasive body surface electrodes, and the utility of CWT frequency analysis versus fast-Fourier transform (FFT)-derived dominant frequency (DF).

Patients with atrial fibrillation (AF) are at an increased risk of thromboembolism and stroke primarily from the development of thrombi within the left atrium. Pathological changes in blood constituents and atrial endothelial damage promote left atrial thrombus formation. It is not known whether factors predisposing to left atrial thrombus formation in AF are disease specific or also evident within the normal heart. The present study examined whether there are differences in platelet reactivity, endothelial function and inflammation in blood samples obtained from intracardiac and peripheral sites in subjects within structurally normal hearts. Sixteen patients with diagnosed left-sided supraventricular tachycardia (SVT) undergoing a routine elective electrophysiological study and ablation were investigated. Blood samples were taken simultaneously from the femoral vein, right atrium and left atrium, immediately following trans-septal puncture and prior to heparin bolus administration. Between peripheral and atrial sample sites, patients with SVT showed no change in platelet reactivity or aggregation (P-selectin (CD62P) P = 0.91; platelet-derived soluble CD40 ligand P = 0.9), thrombus formation (thrombin-antithrombin complex; P = 0.55), endothelial function (von Willebrand factor P = 0.75; asymmetric dimethylarginine (ADMA) P = 0.97; nitric oxide P = 0.61), or inflammation (vascular cell adhesion molecule-1 P = 0.59; intercellular adhesion molecule-1 (ICAM-1) P = 0.69). However, SVT patients had lower ADMA and ICAM-1 levels than AF patients. The present study demonstrates, for the first time, that SVT subjects with structurally normal hearts have consistent haemostatic function between atrial and peripheral sites. These results suggest that the atria of SVT patients do not contain predisposing thrombogenic, endothelial or inflammatory factors that promote and/or initiate thrombus formation. [ABSTRACT FROM AUTHOR]

AF in WPW Syndrome. Aim: We aimed to characterize electrophysiological properties of pulmonary veins (PVs) in patients with Wolff-Parkinson-White (WPW) syndrome and atrial fibrillation (AF), and to compare them to those in patients with WPW without AF. Methods and Results: A total of 31 patients (mean age 40 ± 15 years, 23 males) with WPW were recruited: 16 patients with (AF group) and 15 without (controls) a history of AF. The basic electrophysiological (EPS) and echocardiographic data were not different between the 2 groups. Effective refractory periods (ERPs) of PVs were significantly shorter in the AF group compared to controls: left superior (LS) PV ERP 185±29 versus 230 ± 24 ms, P = 0.001; left inferior PV ERP 198 ± 25 versus 219 ± 26 ms, P = 0.04; right superior (RS) PV ERP 207 ± 25 versus 236 ± 19 ms, P = 0.001; right inferior PV ERP 208 ± 30 versus 240 ± 19 ms, P = 0.003. Maximal veno-atrial conduction delay (i.e., the maximal prolongation of interval from stimulus delivered at PV ostia to proximal coronary sinus after extrastimulus compared to the basic drive cycle) was longer in the AF group when pacing from LSPV (69.3 ± 37.9 vs 32.6 ± 16.1 ms, P = 0.01) and RSPV (74.1 ± 25.9 vs 50.2 ± 26.5 ms, P = 0.04). During EPS, AF was induced more often in the AF group (n = 7) compared to controls (n = 1; P = 0.04). Follow-up revealed that AF recurred in 3 patients in the AF group and none of the controls. Conclusion: Patients with WPW syndrome and AF have shorter ERPs of PVs and greater maximal veno-atrial conduction delay compared to patients with WPW without AF. These findings suggest a potential role of PVs in the development of AF in patients with WPW. (J Cardiovasc Electrophysiol, Vol. 23 p. 280-286, March 2012.) [ABSTRACT FROM AUTHOR]

Summary 1. Endothelial function is an independent predictor of adverse cardiovascular outcomes. The evaluation of endothelial function via changes in vessel diameter or blood flow may be inaccurate during atrial fibrillation (AF) because of non-uniform stroke volumes. 2. Using peripheral arterial tonometry, 50 patients with AF (25 in AF, 25 in sinus rhythm) had digital pulse amplitudes assessed at baseline and during reactive hyperaemia. Hyperaemic responses were compared over varying measurement durations (5, 10 and 15 beats; 30 s; and 1-10 min) to determine optimal measurement duration. 3. Endothelial responses were significantly decreased (indicating endothelial dysfunction) in patients in AF compared with patients in sinus rhythm (1.48 ± 0.60 vs 2.05 ± 1.13, respectively; P = 0.03). 4. Beat-to-beat pulse amplitude was highly variable during AF; although coefficients of variation (CV) for short measurement durations were large, these decreased with longer measurement durations. Bland-Altman plots revealed that limits of agreement for short measurement durations were poor. Limits of agreement became consistently narrower when measurement durations of at least 1 min were used. In contrast, limits of agreement and CV for short measurement durations during sinus rhythm were significantly narrower and smaller, respectively, than during AF over similar measurement durations. 5. Pulse amplitudes are highly variable owing to the non-uniform stroke volumes in AF. Our results suggest that methods of determining endothelial function via vessel diameters or blood flow during reactive hyperaemia should use measurement durations of at least 1 min to ensure accurate and reproducible results. [ABSTRACT FROM AUTHOR]

Electroanatomic Properties of the Pulmonary Veins. Introduction: Rapid PV activity is critical in initiating and maintaining AF. The underlying substrate responsible for this remains uncertain. We sought to identify if patients with paroxysmal (PAF) and persistent atrial fibrillation (PeAF) have an abnormal substrate within the pulmonary veins (PVs). Methods and Results: Thirty-nine patients with AF (21 PAF, 18 PeAF) were compared with 15 age-matched controls with left-sided accessory pathways (AVRT). High-density 3D electroanatomic maps of the PVs were created. PV voltage, conduction, PV muscle sleeve length, effective refractory periods (ERPs) of the PVs, posterior left atrium (PLA), left atrial appendage (LAA) and distal coronary sinus (CSd), and signal complexity were assessed. Compared with controls, the PVs of AF patients had (1) lower mean-voltage and a higher % low-voltage; (2) shorter PV muscle sleeves; (3) slower conduction; (4) shorter ERP; and (5) more prevalent complex signals. Compared with the PAF group, the PeAF group had (1) higher % low voltage; (2) slower conduction; and (3) more complex signals. In PAF patients, the PLA and LAA ERPs were longer than controls and the PV ERP was shorter than controls; in PeAF patients PLA and LAA ERPs were reduced, but to a lesser extent than in the PVs. AF induction occurred during PV ERP testing in both AF groups, but not controls. Conclusions: PAF and PeAF patients demonstrate electrical and electroanatomic remodeling of the PVs compared to control patients without prior AF. Some of these changes were more marked in PeAF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 1083-1091, October 2011) [ABSTRACT FROM AUTHOR]

Adjuvant ablation of complex fractionated atrial electrograms (CFAE) in addition to pulmonary vein isolation (PVI) likely improves procedural outcome compared to PVI alone, particularly in patients with persistent atrial fibrillation (AF). However, CFAE regions can be extensive, occasionally requiring a large amount of extra ablation. Some CFAE regions may also represent passive wavefront collision and may not require ablation. Thus, there is interest in identifying more selective CFAE sites that are critical to AF perpetuation, minimizing the amount of adjuvant ablation that must be performed. The SELECT AF study is a prospective, multicenter, randomized trial comparing a strategy of PVI plus generalized CFAE ablation versus a strategy of PVI plus selective CFAE ablation, focusing on regions of continuous electrical activity (CEA). The primary efficacy endpoint is freedom from atrial arrhythmia at 1 year and the primary safety endpoint is total radiofrequency (RF) delivery time per procedure. Patients undergoing a first time ablation procedure for symptomatic persistent AF will be included. Patients with permanent AF or with left atrial size ≥55 mm will be excluded. Patients will all receive PVI at the time of their ablation, but will be randomized 1:1 to receive adjuvant CFAE ablation using the traditional 'generalized' approach, or a 'selective' approach targeting only CEA regions. Both strategies will be guided by automated mapping algorithms. This study will enroll a minimum of 80 evaluable subjects; 40 in each randomization group. SELECT AF is a randomized trial in patients with persistent AF to evaluate the efficacy of selective versus generalized CFAE ablation in addition to traditional PVI. (J Cardiovasc Electrophysiol, Vol. 22, pp. 541-547 May 2011) [ABSTRACT FROM AUTHOR]

All preclinical studies of atrial remodeling in heart failure (HF) have been confined to a single model of rapid ventricular pacing. To evaluate whether the atrial changes were specific to the model or represented an end result of HF, this study aimed to characterize atrial remodeling in an ovine model of doxorubicin-induced cardiomyopathy. Fourteen sheep, 7 with cardiomyopathy induced by repeated intracoronary doxorubicin infusions and 7 controls, were studied. The development of HF was monitored by cardiac imaging and hemodynamic parameters. Open chest electrophysiological study was performed using custom-made 128-electrode epicardial plaque assessing effective refractory period (ERP) and conduction velocity. Atrial tissues were harvested for structural analysis. The HF group had demonstrable moderate global HF (left ventricular ejection fraction [LVEF]: 37.1 vs 46.4%; P = 0.003) and showed the following compared to controls: left atrial dilatation (P = 0.02) and dysfunction (P = 0.005); longer P-wave duration (P < 0.05); higher ERP at all cycle lengths (P ≤ 0.002) and locations (P < 0.001); slower conduction velocity (P < 0.001); increased conduction heterogeneity index (P < 0.001); increased atrial fibrosis (right atrial [RA]: 5.9 ± 2.6 vs 2.8 ± 0.9%; P < 0.0001, left atrial [LA]: 3.7 ± 2.2 vs 2.4 ± 1.1%; P = 0.002), and longer induced atrial fibrillation (AF) episodes (16 ± 22 vs 2 ± 3 seconds; P = 0.04). In this model of HF, there was significant atrial remodeling characterized by atrial enlargement/dysfunction, increased fibrosis, slowed/heterogeneous conduction, and increased refractoriness associated with more sustained AF. These findings appear the 'same sort' to previous models of HF implicating a final common substrate leading to the development of AF in HF. (J Cardiovasc Electrophysiol, Vol. 22, pp. 175-182, February 2011) [ABSTRACT FROM AUTHOR]

1. High-density cardiac electrophysiological study (EPS) of small animal atria has been limited to optical mapping techniques, which require complex and expensive equipment setup. We aim to evaluate the feasibility of carrying out EPS in isolated atrial tissues using a custom made high-density multiple-electrode array (MEA). 2. Isolated rat atrial preparations were studied. The MEA (4 × 5 mm) consisted of 90 silver chloride coated electrodes (0.1 mm diameter, 0.5 mm pitch) and was connected to a conventional EP system yielding 80 bipolar signals. Atrial tissues were placed over the MEA in a dish bubbled with 100% oxygen and superfused with modified HEPES solution at pH 7.35 and 37°C. Then, 1 mmol of 2,3-butanedione monoxime was added to suppress motion artifacts from muscle contractions. Custom plaque analysis software was used for offline conduction analysis. 3. Isolated atrial tissues showed good viability of > 30 min, allowing ample time for complete EPS. High quality electrograms with excellent signal to noise ratio were obtained. All electrophysiological parameters showed good reproducibility: effective refractory period, conduction velocity and heterogeneity index. Tachycardia was also inducible in these normal atria. 4. The present study shows the feasibility of performing high-density EPS of small isolated atrial tissues with a conventional electrode-based technique. The MEA system is compatible with standard electrophysiology recording systems and provides a novel, inexpensive option for detailed EPS in small animal models. In particular, it presents new research avenues to further explore the mechanisms of atrial arrhythmias in various transgenic and knockout rodent models. [ABSTRACT FROM AUTHOR]

Optimal Right Ventricular Pacing Introduction: Long-term right ventricular apical (RVA) pacing has been associated with adverse effects on left ventricular systolic function; however, the comparative effects of right ventricular outflow tract (RVOT) pacing are unknown. Our aim was therefore to examine the long-term effects of septal RVOT versus RVA pacing on left ventricular and atrial structure and function. Methods: Fifty-eight patients who were prospectively randomized to long-term pacing either from the right ventricular apex or RVOT septum were studied echocardiographically. Left ventricular (LV) and atrial (LA) volumes were measured. LV 2D strain and tissue velocity images were analyzed to measure 18-segment time-to-peak longitudinal systolic strain and 12-segment time-to-peak systolic tissue velocity. Intra-LV synchrony was assessed by their respective standard deviations. Interventricular mechanical delay was measured as the difference in time-to-onset of systolic flow in the RVOT and LV outflow tract. Septal A' was measured using tissue velocity images. Results: Following 29 ± 10 months pacing, there was a significant difference in LV ejection fraction (P < 0.001), LV end-systolic volume (P = 0.007), and LA volume (P = 0.02) favoring the RVOT-paced group over the RVA-paced patients. RVA-pacing was associated with greater interventricular mechanical dyssynchrony and intra-LV dyssynchrony than RVOT-pacing. Septal A' was adversely affected by intra-LV dyssynchrony (P < 0.05). Conclusions: Long-term RVOT-pacing was associated with superior indices of LV structure and function compared with RVA-pacing, and was associated with less adverse LA remodeling. If pacing cannot be avoided, the RVOT septum may be the preferred site for right ventricular pacing. (J Cardiovasc Electrophysiol, Vol. 21, pp. 1120-1126) [ABSTRACT FROM AUTHOR]