Long-term risk of recurrent atrial fibrillation as documented by an implantable monitoring device

Remote Monitoring for Chronic Disease Management: Atrial Fibrillation and Heart Failure

This review aims to cover the latest evidence of remote monitoring of cardiac implantable electronic devices for the management of atrial fibrillation and heart failure. Remote monitoring is useful for early detection for device-detected atrial fibrillation, which increases the risk of thromboembolic events. Early anticoagulation based on remote monitoring potentially reduces the risk of stroke, but optimal alert setting needs to be clarified. Multiparameter monitoring with automatic transmission is useful for heart failure management. Improved adherence to remote monitoring and an optimal algorithm for transmitted alerts and their management are warranted in the management of heart failure.

Comprehensive risk reduction in patients with atrial fibrillation: Emerging diagnostic and therapeutic options

There are exciting new developments in several areas of atrial fibrillation (AF) management that carry the hope of improving outcomes in AF patients. This paper is an executive summary that summarises the proceedings from the 3rd AFNET/EHRA consensus conference on atrial fibrillation, held in Sophia Antipolis from November 7th to 9th 2010, shortly after the release of the new ESC guidelines on AF. The conference was jointly organised by the German Atrial Fibrillation competence NETwork (AFNET) and the European Heart Rhythm Association (EHRA). This executive summary report covers four sections: 1. Risk factors and risk markers for AF, 2. Pathophysiological classification of AF, 3. Relevance of monitored AF duration for AF-related outcomes, and 4. Perspectives and needs for implementing better antithrombotic therapy.

Detecting atrial fibrillation by deep convolutional neural networks

BACKGROUND

Atrial fibrillation (AF) is the most common cardiac arrhythmia. The incidence of AF increases with age, causing high risks of stroke and increased morbidity and mortality. Efficient and accurate diagnosis of AF based on the ECG is valuable in clinical settings and remains challenging. In this paper, we proposed a novel method with high reliability and accuracy for AF detection via deep learning.

METHOD

The short-term Fourier transform (STFT) and stationary wavelet transform (SWT) were used to analyze ECG segments to obtain two-dimensional (2-D) matrix input suitable for deep convolutional neural networks. Then, two different deep convolutional neural network models corresponding to STFT output and SWT output were developed. Our new method did not require detection of P or R peaks, nor feature designs for classification, in contrast to existing algorithms. Finally, the performances of the two models were evaluated and compared with those of existing algorithms.

RESULTS

Our proposed method demonstrated favorable performances on ECG segments as short as 5 s. The deep convolutional neural network using input generated by STFT, presented a sensitivity of 98.34%, specificity of 98.24% and accuracy of 98.29%. For the deep convolutional neural network using input generated by SWT, a sensitivity of 98.79%, specificity of 97.87% and accuracy of 98.63% was achieved.

CONCLUSION

The proposed method using deep convolutional neural networks shows high sensitivity, specificity and accuracy, and, therefore, is a valuable tool for AF detection.

When Silence Isn't Golden: The Case of "Silent" Atrial Fibrillation

Silent atrial fibrillation (AF) is common. In some patients, it is the only manifestation of AF, while in others, the AF may be symptomatic or both symptomatic and asymptomatic. Regardless, however, to date, the significance, detection, and management considerations for silent AF have been incompletely elucidated. This current study aimed to review, for both the current clinician and investigator, considerations and attitudes and the ongoing studies, respectively, with respect to silent AF. The methods used were a literature review and personal trial and clinical experience; the frequency of silent AF, concerns regarding silent AF, methods to detect silent AF, and prospective trials focused on the detection and management of silent AF were considered. The results of the literature search indicated that recently conducted relevant trials, such as PREDATE AF, ASSERT-II, and REVEAL AF, have shown that silent AF is frequent in patients with risk markers for AF and stroke in whom no prior AF history is present, and in whom no pacemaker or implantable cardioverter-defibrillator implantations have been previously performed. Furthermore, the GLORIA-AF Registry has reported the observance of more permanent AF and more prior strokes in asymptomatic patients. Ongoing trials such as ARTESiA and NOAH-AFNET 6 are expected to clarify the benefits and risks of oral anticoagulation in patients with silent AF. At present, when silent AF is detected in patients with stroke risk markers, most practitioners initiate an anticoagulation regimen.

Left ventricular torsional parameters before and after atrial fibrillation ablation: a velocity vector imaging study

BACKGROUND AND AIM

Effects of atrial fibrillation (AF) and its ablative treatment on LV torsion have not yet been fully investigated. This study aimed to examine whether AF patterns of LV contraction and its ablative correction can exert a significant impact on LV torsion by velocity vector imaging (VVI).

METHODS

This case-control study conducted in Rajaie Cardiovascular, Medical and Research Center between October 2012 and June 2013. Study participants were 30 consecutive patients with symptomatic paroxysmal AF who met the inclusion criteria. The control group included 24 healthy participants with no history of cardiovascular disease. All individuals were in sinus rhythm at the time of echocardiography before and after the ablation procedure. Two-dimensional (2D) and Doppler echocardiography on a commercially available ultrasound system was performed for all the patients. Scanning was done by a wide-band ultrasound transducer with the frequency range between 2.5-3.5 MHz. The two short-axis views at basal and apical levels were subsequently processed off-line by VVI XStrain software. In order for data analysis, SPSS 16 utilized using paired and independent t-test. p-value ≤0.05 was considered significant.

RESULTS

LV torsion (°/cm) mean ± SD was significantly lower in paroxysmal AF patients before ablation (0.8±0.3) than the control group (1.5±0.4) (p<0.001) and increased significantly after ablation (1.1±0.5) compared with before ablation (p=0.004), but still significantly lower than the control group (p=0.003). LV Twist, twist rate and untwist rate mean ± SD were significantly lower in paroxysmal AF patients before ablation than the control group and increased significantly after ablation compared with before ablation, but still significantly lower than the control group.

CONCLUSION

Subclinical LV dysfunction may be detected in paroxysmal AF rhythm by measuring torsional parameters through VVI which improves after AF ablation.

Frequency of arrhythmia symptoms and acceptability of implantable cardiac monitors in Hemodialysis patients

Background

Arrhythmia-related complications and sudden death are common in dialysis patients. However, routine cardiac monitoring has so far not been feasible. Miniaturization of implantable cardiac monitors offers a new paradigm for detection and management of arrhythmias in dialysis patients. The goal of our study was to determine the frequency of arrhythmia-related symptoms in hemodialysis patients and to assess their willingness to undergo implantation of a cardiac monitor.

Methods

We conducted a survey of in-center hemodialysis patients at a hemodialysis clinic in Baltimore, Maryland. We assessed the frequency of arrhythmia-related symptoms and willingness to undergo placement of an implantable cardiac monitor (LINQ, Medtronic Inc.).

Results

Forty six patients completed the survey. The mean age of the survey respondents was 59 years and 65% were male. Symptoms were common with 74% (n = 34) of participants reporting at least one arrhythmia-related symptom and many [22% (n = 10)] had all 3 symptoms. Among the patients with symptoms, 57% (n = 26) reported “heart skipping beats, flopping in chest or beating very hard,” 61% (n = 28) reported “heart racing (palpitations),” and 37% (n = 17) reported feeling that they “passed out or almost passed out.” The majority of the patients felt that the timing of the symptoms was unrelated to dialysis treatments. The acceptability of the monitoring device implantation was high, with 59% (n = 20) of patients with symptoms and 50% (n = 6) of patients without symptoms willing to consider it. The main reason for not considering the device was not wanting to have an implanted device.

Conclusion

The prevalence of arrhythmia-related symptoms is high in hemodialysis patients and the majority would consider an implantable cardiac monitor if recommended by their physicians. Routine implantation of cardiac monitoring devices to manage arrhythmias in dialysis patients may be feasible and will provide further insights on the leading causes of morbidity and mortality in dialysis patients.

Electronic supplementary material

The online version of this article (10.1186/s12882-017-0740-1) contains supplementary material, which is available to authorized users.

Cardioverting acute atrial fibrillation and the risk of thromboembolism: not all patients are created equal

Current guidelines support the well-established clinical practice that patients who present with atrial fibrillation (AF) of less than 48 hours duration should be considered for cardioversion, even in the absence of pre-existing anticoagulation. However, with increasing evidence that short runs of AF confer significant risk of stroke, on what evidence is this 48-hour rule based and is it time to adopt a new approach? We review existing evidence and suggest a novel approach to risk stratification in this setting. Overall, the risk of thromboembolism associated with acute cardioversion of patients with AF that is estimated to be of <48 hours duration is low. However, this risk varies widely depending on patient characteristics. From existing evidence, we show that using the CHA2DS2-VASc score may allow better selection of appropriate patients in order to prevent exposing specific patient groups to an unacceptably high risk of a potentially devastating complication.

Atrial fibrillation detected by continuous electrocardiographic monitoring using implantable loop recorder to prevent stroke in individuals at risk (the LOOP study): Rationale and design of a large randomized controlled trial

Atrial fibrillation (AF) increases the rate of stroke 5-fold, and AF-related strokes have a poorer prognosis compared with non-AF-related strokes. Atrial fibrillation and stroke constitute an intensifying challenge, and health care organizations are calling for awareness on the topic. Previous studies have demonstrated that AF is often asymptomatic and consequently undiagnosed. The implantable loop recorder (ILR) allows for continuous, long-term electrocardiographic monitoring with daily transmission of arrhythmia information, potentially leading to improvement in AF detection and stroke prevention.

METHODS

The LOOP study is an investigator-initiated, randomized controlled trial with 6,000 participants randomized 3:1 to a control group or to receive an ILR with continuous electrocardiographic monitoring. Participants are identified from Danish registries and are eligible for inclusion if 70years or older and previously diagnosed as having at least one of the following conditions: hypertension, diabetes mellitus, heart failure, or previous stroke. Exclusion criteria include history of AF and current oral anticoagulation treatment. When an AF episode lasting ≥6minutes is detected, oral anticoagulation will be initiated according to guidelines. Expected follow-up is 4years. The primary end point is time to stroke or systemic embolism, whereas secondary end points include time to AF diagnosis and death.

CONCLUSION

The LOOP study will evaluate health benefits and cost-effectiveness of ILR as a screening tool for AF to prevent stroke in patients at risk. Secondary objectives include identification of risk factors for the development of AF and characterization of arrhythmias in the population. The trial holds the potential to influence the future of stroke prevention.

Effects of Alpha Lipoic Acid on Multiple Cytokines and Biomarkers and Recurrence of Atrial Fibrillation Within 1 Year of Catheter Ablation

Catheter ablation (CA) is a procedure commonly used to restore sinus rhythm in patients with atrial fibrillation (AF). However, AF recurrence after CA remains a relevant clinical issue. We tested the effects of an oral antioxidant treatment (alpha lipoic acid [ALA]) on AF recurrence post-CA. Patients with paroxysmal AF have been enrolled in a randomized, prospective, double-blind, controlled placebo trial. After CA, patients have been randomly assigned to receive ALA oral supplementation (ALA group) or placebo (control group) and evaluated at baseline and after a 12-month follow-up: 73 patients completed the 12-month follow-up (ALA: 33 and control: 40). No significant difference has been detected between the 2 groups at baseline. Strikingly, 1 year after CA, ALA therapy significantly reduced serum markers of inflammation. However, there was no significant difference in AF recurrence events at follow-up comparing ALA with placebo group. Multivariate analysis revealed that the only independent prognostic risk factor for AF recurrence after CA is age. In conclusion, ALA therapy reduces serum levels of common markers of inflammation in ablated patients. Nevertheless, ALA does not prevent AF recurrence after an ablative treatment.

[Implantable loop recorder in atrial fibrillation and after catheter ablation]

BACKGROUND

Implantable loop recorders (ILR) are an established diagnostic method for detection of cardiac arrhythmias including atrial fibrillation.

OBJECTIVE

The aim of this work is to provide an overview of available data and indications of ILR in atrial fibrillation, especially after catheter ablation, in order to illustrate practice-oriented recommendations.

MATERIALS AND METHODS

We conducted a selective PubMed literature search.

RESULTS AND DISCUSSION

ILR can record asymptomatic/rare atrial fibrillation episodes and prevent thromboembolic events by allowing timely initiation of oral anticoagulation. They can be used to assess therapeutic success after percutaneous or surgical ablation, if despite increased thromboembolic risk, no oral anticoagulation is desired. ILR equipped with remote monitoring function and special P wave detection algorithms may improve diagnostic confidence.

The Role of Pharmacogenetics in Atrial Fibrillation Therapeutics: Is Personalized Therapy in Sight?

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia worldwide requiring therapy. Despite recent advances in catheter-based and surgical therapy, antiarrhythmic drugs (AADs) remain the mainstay of treatment for symptomatic AF. However, response in individual patients is highly variable with over half the patients treated with rhythm control therapy experiencing recurrence of AF within a year. Contemporary AADs used to suppress AF are incompletely and unpredictably effective and associated with significant risks of proarrhythmia and noncardiac toxicities. Furthermore, this "one-size" fits all strategy for selecting antiarrhythmics is based largely on minimizing risk of adverse effects rather than on the likelihood of suppressing AF. The limited success of rhythm control therapy is in part due to heterogeneity of the underlying substrate, interindividual differences in disease mechanisms, and our inability to predict response to AADs in individual patients. Genetic studies of AF over the past decade have revealed that susceptibility to and response to therapy for AF is modulated by the underlying genetic substrate. However, the bedside application of these new discoveries to the management of AF patients has thus far been disappointing. This may in part be related to our limited understanding about genetic predictors of drug response in general, the challenges associated with determining efficacy of response to AADs, and lack of randomized genotype-directed clinical trials. Nonetheless, recent studies have shown that common AF susceptibility risk alleles at the chromosome 4q25 locus modulated response to AADs, electrical cardioversion, and ablation therapy. This monograph discusses how genetic approaches to AF have not only provided important insights into underlying mechanisms but also identified AF subtypes that can be better targeted with more mechanism-based "personalized" therapy.

Predictors and long-term clinical outcomes of newly developed atrial fibrillation in patients with cardiac implantable electronic devices

OBJECTIVE

To evaluate predictors and long-term prognosis of atrial fibrillation (AF) following cardiac implantable electronic device (CIED) implantation in patients without history of AF.

METHODS

From May 1994 to April 2014, 1825 patients with CIED were enrolled in a retrospective, single-center registry. A total of 880 patients from the registry without prior documented AF history were included in the final analysis and were placed into either non-detected AF (NDAF) group or CIED-detected AF group according to development of AF over a follow-up period of 7 years. AF development was defined as any paroxysmal atrial tachyarrhythmia (atrial rate ≥ 180 beats/min) lasting at least 5 minutes according to CIED records.

RESULTS

Overall, 122 (13.8%) of the 880 patients experienced new development of AF during follow-up period. According to multivariate analysis, the independent predictors for development of AF were prior heart failure (hazard ratio [HR], 2.40; 95% confidence interval [CI], 1.50-3.85; P < 0.001), prior sinus node dysfunction (HR, 2.33; 95% CI, 1.62-3.55; P < 0.001), and left atrium volume index of 38.5 mL/m or more (HR, 2.01; 95% CI, 1.23-3.30; P = 0.005). In CDAF group, the risk of heart failure readmission (adjusted HR, 3.79; 95% CI, 1.99-7.22; P < 0.001) and stroke readmission (adjusted HR, 5.33; 95% CI, 1.58-17.97; P = 0.007) was higher than in nondetected AF group.

CONCLUSION

In patients with CIED, prior history of heart failure, sinus node dysfunction, and LA volume index ≥38.5 mL/m were independent predictors of new AF cases. Newly developed AF was significantly associated with increased risk of HF and stroke readmission, according to long-term follow up.

Detecting nonvalvular atrial fibrillation and anticoagulant therapy in cardioembolic ischemic stroke

Nonvalvular Atrial fibrillation (NVAF) is the most common cardiac arrhythmia associated with an increase in risk of stroke and systemic thromboembolism. Strokes related to AF are associated with higher mortality, greater disability, longer hospital stays, and lower chance of being discharged home. The present review will focus on the current status of detecting NVAF and stroke prevention when there is AF. The CHA2DS2-VASc risk stratification scheme is discussed for the identification of patients who are at risk for thromboembolic stroke related to NVAF. Patient with a CHA2DS2-VASc score of 2 or greater are candidates for warfarin or a novel oral anticoagulant, irrespective of whether the strategy is for rate or rhythm control. Finally, guidelines and landmark clinical trials in NVAF patients with primary or secondary stroke prevention are discussed.

Atrial fibrillation burden and atrial fibrillation type: Clinical significance and impact on the risk of stroke and decision making for long-term anticoagulation

Atrial fibrillation (AF) is a common arrhythmia increasing the risk of morbidity and adverse outcomes (stroke, heart failure, death). AF is found in 1-2% of the general population, with increasing prevalence with aging. Its exact epidemiological profile is incomplete and underestimated, because 10-40% of AF patients (particularly the elderly) can be asymptomatic ("clinically silent or subclinical AF"), with occasional electrocardiographic diagnosis. The research interest on silent AF has increased by the evidence that its outcome is no less severe, in terms of risks of stroke and death, than that for symptomatic patients. Data collected from more than 18,000 patients indicate that cardiac implantable electrical devices (CIEDs) are validated tools for detecting silent AF and measuring the time spent in AF, defined as "AF burden." A maximum daily AF burden of ≥5-6min, but particularly ≥1h, is associated with a significant increase in the risk of stroke, and may be clinically relevant to improve current risk stratification based on risk scores and for "personalizing" prescription of oral anticoagulants. An in-depth study of the temporal relationship between AF and ischemic stroke showed that data from CIEDs reveal a complex scenario, by which AF is certainly a risk factor for cardioembolic stroke, with a cause-effect relationship related to atrial thrombi, but can also be a simple "marker of risk," with a noncausal association with stroke. In such cases, stroke is possibly related to atheroemboli from the aorta, the carotid arteries, or other sources.

Remote monitoring of implantable devices: Should we continue to ignore it?

The number of patients with implantable cardioverter defibrillators (ICDs) is increasing. In addition to improve survival, ICD can collect data related to device function and physiological parameters. Remote monitoring (RM) of these data allows early detection of technical or clinical problems and a prompt intervention (reprogramming device or therapy adjustment) before the patient require hospitalization. RM is not a substitute for emergency service and its consultation is now limited during working hours. Thus, a consent form is required to inform patients about benefits and limitations. The available studies indicate that remote monitoring is more effective than traditional calendar face to face based encounters. RM is safe, highly reliable, cost efficient, allows quick reply to failures, and reduces the number of scheduled visits and the incidence of inappropriate shocks with a positive impact on survival. It follows that RM has the credentials to be the standard of care for ICD management; however, unfortunately, there is a delay in physician acceptance and implementation. The recent observations from randomized IN-TIME study that showed a clear survival benefit with RM in heart failure patients have encouraged us to review both the negative and positive aspects of RM collected in a little more than a decade.

A Comparison of Atrial Fibrillation Monitoring Strategies After Cryptogenic Stroke (from the Cryptogenic Stroke and Underlying AF Trial)

Ischemic stroke cause remains undetermined in 30% of cases, leading to a diagnosis of cryptogenic stroke. Paroxysmal atrial fibrillation (AF) is a major cause of ischemic stroke but may go undetected with short periods of ECG monitoring. The Cryptogenic Stroke and Underlying Atrial Fibrillation trial (CRYSTAL AF) demonstrated that long-term electrocardiographic monitoring with insertable cardiac monitors (ICM) is superior to conventional follow-up in detecting AF in the population with cryptogenic stroke. We evaluated the sensitivity and negative predictive value (NPV) of various external monitoring techniques within a cryptogenic stroke cohort. Simulated intermittent monitoring strategies were compared to continuous rhythm monitoring in 168 ICM patients of the CRYSTAL AF trial. Short-term monitoring included a single 24-hour, 48-hour, and 7-day Holter and 21-day and 30-day event recorders. Periodic monitoring consisted of quarterly monitoring through 24-hour, 48-hour, and 7-day Holters and monthly 24-hour Holters. For a single monitoring period, the sensitivity for AF diagnosis was lowest with a 24-hour Holter (1.3%) and highest with a 30-day event recorder (22.8%). The NPV ranged from 82.3% to 85.6% for all single external monitoring strategies. Quarterly monitoring with 24-hour Holters had a sensitivity of 3.1%, whereas quarterly 7-day monitors increased the sensitivity to 20.8%. The NPVs for repetitive periodic monitoring strategies were similar at 82.6% to 85.3%. Long-term continuous monitoring was superior in detecting AF compared to all intermittent monitoring strategies evaluated (p <0.001). Long-term continuous electrocardiographic monitoring with ICMs is significantly more effective than any of the simulated intermittent monitoring strategies for identifying AF in patients with previous cryptogenic stroke.

Misconceptions and Facts About Atrial Fibrillation

Atrial fibrillation is an increasingly common arrhythmia associated with substantial but largely preventable risk of ischemic stroke. There has been an exponential increase in research related to atrial fibrillation in recent years, resulting in some major advances in the therapeutic management. Novel oral anticoagulant agents have become available and require thorough assessment of risk-to-benefit ratio. While the knowledge is rapidly accumulating, the basic principles of atrial fibrillation management remain proper recognition, risk stratification, and appropriate prevention of thromboembolic complications. This review highlights some common misconceptions about atrial fibrillation.

Different distribution of Helicobacter pylori EPIYA- cagA motifs and dupA genes in the upper gastrointestinal diseases and correlation with clinical outcomes in iranian patients

AIM

Our aim was to determine the EPIYA-cagA Phosphorylation sites and dupA gene in H. pylori isolates among patients with upper gastrointestinal diseases.

BACKGROUND

Pathogenicity of the cagA-positive Helicobacter pylori is associated with EPIYA motifs and higher number of EPIYA-C segments is a risk factor of gastric cancer, while duodenal ulcer-promoting gene (dupA) is determined as a protective factor against gastric cancer.

PATIENTS AND METHODS

A total of 280 non-repeated gastric biopsies obtained from patients undergoing endoscopy from January 2013 till July 2013. Samples were cultured on selective horse blood agar and incubated in microaerophilic atmosphere. The isolated organisms were identified as H. pylori by Gram staining and positive oxidase, catalase, and urease tests. Various motif types of cagA and the prevalence of dupA were determined by PCR method.

RESULTS

Out of 280 specimens, 128 (54.7%) isolated organisms were identified as H. pylori. Of 120 H. pylori isolates, 35.9% were dupA positive and 56.26% were cagA positive, while cagA with ABC and ABCC motifs were 55.5% and 44.5%, respectively. Fifty six percent of the isolates with the ABCC motif have had dupA genes. We also found a significant association between strains with genotypes of dupA-ABC and duodenal ulcer disease (p = 0.007).

CONCLUSION

The results of this study showed that the prevalence of cagA-positive H. pylori in Shiraz was as high as in western countries and higher numbers of EPIYA-C segments were seen in gastric cancer patients. We may also use dupA as a prognostic and pathogenic marker for duodenal ulcer disease and cagA with the segment C for gastric cancer and gastric ulcer disease in this region.

Heartbeat Cycle Length Detection by a Ballistocardiographic Sensor in Atrial Fibrillation and Sinus Rhythm

Background. Heart rate monitoring is especially interesting in patients with atrial fibrillation (AF) and is routinely performed by ECG. A ballistocardiography (BCG) foil is an unobtrusive sensor for mechanical vibrations. We tested the correlation of heartbeat cycle length detection by a novel algorithm for a BCG foil to an ECG in AF and sinus rhythm (SR). Methods. In 22 patients we obtained BCG and synchronized ECG recordings before and after cardioversion and examined the correlation between heartbeat characteristics. Results. We analyzed a total of 4317 heartbeats during AF and 2445 during SR with a correlation between ECG and BCG during AF of r = 0.70 (95% CI 0.68–0.71, P < 0.0001) and r = 0.75 (95% CI 0.73–0.77, P < 0.0001) during SR. By adding a quality index, artifacts could be reduced and the correlation increased for AF to 0.76 (95% CI 0.74–0.77, P < 0.0001, n = 3468) and for SR to 0.85 (95% CI 0.83–0.86, P < 0.0001, n = 2176). Conclusion. Heartbeat cycle length measurement by our novel algorithm for BCG foil is feasible during SR and AF, offering new possibilities of unobtrusive heart rate monitoring. This trial is registered with IRB registration number EK205/11. This trial is registered with clinical trials registration number NCT01779674.

Usefulness of brain natriuretic peptide for predicting left atrial appendage thrombus in patients with unanticoagulated nonvalvular persistent atrial fibrillation

BACKGROUND

The CHADS2 scoring system is simple and widely accepted for predicting thromboembolism in patients with nonvalvular atrial fibrillation (NVAF). Although congestive heart failure (CHF) is a component of the CHADS2 score, the definition of CHF remains unclear. We previously reported that the presence of CHF was a strong predictor of left atrial appendage (LAA) thrombus. Therefore, the present study aimed to elucidate the relationship between LAA thrombus and the brain natriuretic peptide (BNP) level in patients with unanticoagulated NVAF.

METHODS

The study included 524 consecutive patients with NVAF who had undergone transesophageal echocardiography to detect intracardiac thrombus before cardioversion between January 2006 and December 2008, at Hiroshima City Asa Hospital. The exclusion criteria were as follows: paroxysmal atrial fibrillation, unknown BNP levels, prothrombin time international normalized ratio ≥2.0, and hospitalization for systemic thromboembolism.

RESULTS

Receiver operating characteristic analysis yielded optimal plasma BNP cut-off levels of 157.1 pg/mL (area under the curve, 0.91; p<0.01) and 251.2 pg/mL (area under the curve, 0.70; p<0.01) for identifying CHF and detecting LAA thrombus, respectively. Multivariate analyses demonstrated that a BNP level >251.2 pg/mL was an independent predictor of LAA thrombus (odds ratio, 3.51; 95% confidence interval, 1.08-10.7; p=0.046).

CONCLUSIONS

In patients with unanticoagulated NVAF, a BNP level >251.2 pg/mL may be helpful for predicting the incidence of LAA thrombus and may be used as a surrogate marker of CHF. The BNP level is clinically useful for the risk stratification of systemic thromboembolism in patients with unanticoagulated NVAF.

Detecting and monitoring arrhythmia recurrence following catheter ablation of atrial fibrillation

Atrial fibrillation (AF) is the most common arrhythmia prompting clinical presentation, is associated with significant morbidity and mortality. The incidence and prevalence of this arrhythmia is expected to grow significantly in the coming decades. Of the available pharmacologic and non-pharmacologic treatment options, the fastest growing and most intensely studied is catheter-based ablation therapy for AF. Given the varying success rates for AF ablation, the increasingly complex factors that need to be taken into account when deciding to proceed with ablation, as well as varying definitions of procedural success, accurate detection of arrhythmia recurrence and its burden is of significance. Detecting and monitoring AF recurrence following catheter ablation is therefore an important consideration. Multiple studies have demonstrated the close relationship between the intensity of rhythm monitoring with wearable ambulatory cardiac monitors, or implantable cardiac rhythm monitors and the detection of arrhythmia recurrence. Other studies have employed algorithms dependent on intensive monitoring and arrhythmia detection in the decision tree on whether to proceed with repeat ablation or medical therapy. In this review, we discuss these considerations, types of monitoring devices, and implications for monitoring AF recurrence following catheter ablation.

Beneficial effects of losartan for prevention of paroxysmal atrial fibrillation in patients with sick sinus syndrome: analysis with memory function of pacemaker

Renin-angiotensin system (RAS) inhibitors may be useful in preventing the occurrence of paroxysmal atrial fibrillation (PAF). However, evaluation of such effect is difficult because many PAF episodes are asymptomatic and not all episodes are detected by intermittent electrocardiographic monitoring. A pacemaker has been developed with dedicated functions for AF detection and electrocardiogram storage. Accordingly, we examined the effect of losartan, an angiotensin receptor blocker on PAF occurrence using this new modality. We enrolled 70 consecutive patients who had undergone dual-chamber pacemaker implantation for sick sinus syndrome. Finally, 62 patients participated in the study. Thirty patients were randomized to the losartan group (mean 43 ± 12 mg/day) and 32 patients to the control group. They were followed up for 3 months. The frequency, the maximum duration and the total duration of PAF recorded by the stored electrocardiograms for the last 1 month during the observation period and study period were compared between the two groups. The change in the frequency of PAF from the observation period in the losartan and control groups was similar (-35 ± 25 vs. -67 ± 62 times; NS). However, the change in the maximum duration and the total duration of PAF was significantly shorter in the losartan group than in the control group (-493 ± 158 vs. -10 ± 69 min; p < 0.05, and -4007 ± 2334 vs. 1119 ± 714 min; p < 0.05, respectively). Losartan suppressed the maximum duration and the total duration of PAF in patients with sick sinus syndrome without hemodynamic changes. This is the first study to show the effect of a renin-angiotensin system inhibitor on the secondary prevention of PAF using the dedicated functions of a pacemaker for PAF detection and electrocardiogram storage.

Long-term outcomes of secondary atrial fibrillation in the community: the Framingham Heart Study

BACKGROUND

Guidelines have proposed that atrial fibrillation (AF) can occur as an isolated event, particularly when precipitated by a secondary, or reversible, condition. However, knowledge of long-term AF outcomes after diagnosis during a secondary precipitant is limited.

METHODS AND RESULTS

In 1409 Framingham Heart Study participants with new-onset AF, we examined associations between first-detected AF episodes occurring with and without a secondary precipitant and both long-term AF recurrence and morbidity. We selected secondary precipitants based on guidelines (surgery, infection, acute myocardial infarction, thyrotoxicosis, acute alcohol consumption, acute pericardial disease, pulmonary embolism, or other acute pulmonary disease). Among 439 patients (31%) with AF diagnosed during a secondary precipitant, cardiothoracic surgery (n=131 [30%]), infection (n=102 [23%]), noncardiothoracic surgery (n=87 [20%]), and acute myocardial infarction (n=78 [18%]) were most common. AF recurred in 544 of 846 eligible individuals without permanent AF (5-, 10-, and 15-year recurrences of 42%, 56%, and 62% with versus 59%, 69%, and 71% without secondary precipitants; multivariable-adjusted hazard ratio, 0.65 [95% confidence interval, 0.54-0.78]). Stroke risk (n=209/1262 at risk; hazard ratio, 1.13 [95% confidence interval, 0.82-1.57]) and mortality (n=1098/1409 at risk; hazard ratio, 1.00 [95% confidence interval, 0.87-1.15]) were similar between those with and without secondary precipitants, although heart failure risk was reduced (n=294/1107 at risk; hazard ratio, 0.74 [95% confidence interval, 0.56-0.97]).

CONCLUSIONS

AF recurs in most individuals, including those diagnosed with secondary precipitants. Long-term AF-related stroke and mortality risks were similar between individuals with and without secondary AF precipitants. Future studies may determine whether increased arrhythmia surveillance or adherence to general AF management principles in patients with reversible AF precipitants will reduce morbidity.

Significance and Management Strategies for Patients with Asymptomatic Atrial Fibrillation

Atrial fibrillation (AF) is a common and refractory arrhythmia. Prevalence of AF increases with age. Asymptomatic AF is a state of asymptomatic episodes of arrhythmia and its exact prevalence remains unknown. Ablation and therapy with antiarrhythmic agents may predispose to asymptomatic AF. Detection of silent AF is crucial for prevention of ischaemic stroke. Progress in continuous ECG monitoring by Holter ECG, telemetry methods or implantable devices can provide a useful tools for identifying silent AF. Simple screening procedures like pulse examination and ambulatory ECG may be helpful in arrhythmia detection and logically - ischemic stroke prevention.

A placebo-controlled, double-blind, randomized, multicenter study to assess the effects of dronedarone 400 mg twice daily for 12 weeks on atrial fibrillation burden in subjects with permanent pacemakers

Purpose

Dronedarone is a benzofuran derivative with a pharmacological profile similar to amiodarone but has a more rapid onset of action and a much shorter half-life (13–19 h). Our goal was to evaluate the efficacy of dronedarone in atrial fibrillation (AF) patients using dual-chamber pacemakers capable of quantifying atrial fibrillation burden.

Methods

Pacemakers were adjusted to optimize AF detection. Patients with AF burden >1 % were randomized to dronedarone 400 mg twice daily (BID) or placebo. Pacemakers were interrogated after 4 and 12 weeks of treatment. The primary endpoint was the change in AF burden from baseline over the 12-week treatment period. Patients with permanent AF, severe/recently decompensated heart failure, and current use of antiarrhythmic drugs were excluded. AF burden was assessed by a core laboratory blinded to treatment assignment.

Results

From 285 patients screened, 112 were randomized (mean age 76 years, 60 % male, 84 % hypertensive, 65 % with sick sinus syndrome, 26 % with diabetes mellitus type II, 15 % with heart failure). Baseline mean (SEM) AF burden was 8.77 % (0.16) for placebo and 10.14 % (0.17) for dronedarone. Over the 12-week study period, AF burden compared to baseline decreased by 54.4 % (0.22) (P = 0.0009) with dronedarone and trended higher by 12.8 % (0.16) (P = 0.450) with placebo. The absolute change in burden was decreased by 5.5 % in the dronedarone group and increased by 1.1 % in the placebo group. Heart rate during AF was reduced to approximately 4 beats/min with dronedarone (P = 0.285). Adverse events were higher with dronedarone compared to placebo (65 vs 56 %).

Conclusions

Dronedarone reduced pacemaker-assessed the relative AF burden compared to baseline and placebo by over 50 % during the 12-week observation period.

Submuscular implantation of insertable cardiac monitors improves the reliability of detection of atrial fibrillation

PURPOSE

Diagnosing atrial fibrillation (AF) is highly relevant, as specific secondary prevention is of high importance. Recently, insertable cardiac monitors (ICMs) have been introduced for continuous monitoring to detect asymptomatic episodes of AF. The detection of AF remains challenging due to a relevant incidence of artifacts. This study aimed to compare the effectivity of ICM when placed in a subcutaneous or in a submuscular localization, respectively.

METHODS

We retrospectively analyzed data from 30 patients undergoing pulmonary vein isolation (PVI) for AF and consecutive ICM implantation. ICMs were implanted in two locations: either subcutaneously and parasternally (SC) or under the left major pectoral muscle (SP). Interrogations were continuously retrieved using remote monitoring and during repeated visits in our outpatient clinic. The transmission protocols were scanned for detected AF, and it was ruled by two blinded investigators, if detection was correct or incorrect.

RESULTS

Mean age was 67 ± 10 years, 56% men, 50% paroxysmal AF. In 14 of the patients, the ICM was implanted at a SC localization and in 16 patients subpectorally. R-wave amplitude was significantly higher in patents with SP implantation. There were 670 transmitted protocols including 1024 episodes detected as AF. Of these, 54% were correctly recognized as AF in the SC group. In the SP group, 85% of the recorded episodes were correctly recognized as AF (p = 0.03). The remaining episodes in both groups showed sinus rhythm with misinterpreted artifacts.

CONCLUSIONS

To improve effectiveness of detecting AF episodes, it is useful to implant subpectorally.

Accuracy of patient perception of their prevailing rhythm: a comparative analysis of monitor data and questionnaire responses in patients with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) guidelines recommend that symptom relief be a primary goal in management. However, patient perception of their prevailing rhythm is often inaccurate, complicating symptom-targeted treatment.

OBJECTIVE

The purpose of this study was to evaluate the accuracy of patient perception of their prevailing rhythm and identify factors that predict inaccuracies.

METHODS

Demographic and health status data were captured by questionnaires for 458 outpatients with documented AF. AF burden (%) was captured by 1-week continuous heart monitors. Patients estimated the length and frequency of their AF episodes by completing the AF Symptom Severity questionnaire. Patient reports were compared to AF burden, and outliers were identified and broken into 2 groups: patients with AF burden <10% who indicated near-continuous AF (overestimators) and patients with AF burden >90% who estimated little to no AF (underestimators). Multinomial logistic regression was used to identify predictors of inaccuracies (over- or underestimators).

RESULTS

By continuous monitor, 15% of patients were found to be over- or underestimators. Persistent AF, female sex, older age, anxiety, and depression were predictive of inaccurate patient perception. Persistent AF, female sex, and older age were predictive of underestimating, while mood disorders (anxiety and depression) were predictive of overestimating. The prevalence of underestimators was nearly twice that of overestimators.

CONCLUSION

Sex, age, and mood disorders are among factors that lead to inaccurate patient perception of their prevailing rhythm in patients with AF. Such modulating factors should be considered when evaluating treatment strategies. Consideration should be given to more liberal use of heart monitors in these patient populations to better target therapy.

Untreated atrial fibrillation in the United Kingdom: Understanding the barriers and treatment options

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia and a major preventable cause of stroke and hospitalization. Its prevalence is on the rise worldwide and experts believe it will continue to rise for the foreseeable future, due to the ageing population and increased survival from conditions associated with AF. Despite the fact that oral anticoagulation is effective in preventing strokes due to AF, there is extensive evidence suggesting this therapy remains underused. Barriers to the prescription of anticoagulation include patients' age per se, comorbidities, inadequate risk stratification, perceived risk of falls and bleeding, and the difficulty in achieving a stable international normalized ratio (INR) on warfarin. Also, asymptomatic patients with AF may not be identified and therefore not be candidates for anticoagulation. Physicians need continued better education on the identification of patients at risk of stroke and management of oral anticoagulation. This article reviews the barriers to anticoagulation in patients with AF in the United Kingdom and considers how those barriers may be overcome.