Comparison of antiarrhythmic drug therapy and radiofrequency catheter ablation in patients with paroxysmal atrial fibrillation: a randomized controlled trial

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.

Radiofrequency catheter ablation maintains its efficacy better than antiarrhythmic medication in patients with paroxysmal atrial fibrillation: On-treatment analysis of the randomized controlled MANTRA-PAF trial

BACKGROUND

The Medical ANtiarrhythmic Treatment or Radiofrequency Ablation in Paroxysmal Atrial Fibrillation (MANTRA-PAF) is a randomized trial comparing radiofrequency catheter ablation (RFA) to antiarrhythmic drugs (AADs) as first-line treatment of paroxysmal atrial fibrillation (PAF). In order to eliminate the clouding effect of crossover we performed an on-treatment analysis of the data.

METHODS AND RESULTS

Patients (n=294) were divided into three groups: those receiving only the assigned therapy (RFA and AAD groups) and those receiving both therapies (crossover group). The primary end points were AF burden in 7-day Holter recordings at 3, 6, 12, 18, and 24 months and cumulative AF burden in all recordings. At 24 months, AF burden was significantly lower in the RFA (n=110) than in the AAD (n=92) and the crossover (n=84) groups (90th percentile 1% vs. 10% vs. 16%, P=0.007), and more patients were free from any AF (89% vs. 73% vs. 74%, P=0.006). In the RFA, AAD and the crossover groups 63%, 59% and 21% (P<0.001) of the patients had no AF episodes in any Holter recording, respectively. Quality of life improved significantly in all groups. There were no differences in serious adverse events between the RFA, AAD and crossover groups (19% vs. 8% vs. 23%) (P=0.10).

CONCLUSIONS

In the treatment of antiarrhythmic therapy naïve patients with PAF long-term efficacy of RFA was superior to AAD therapy. Thus, it is reasonable to offer RFA as first-line treatment for highly symptomatic patients who accept the risks of the procedure and are aware of frequent need for reablation(s).

Ablation of atrial fibrillation

Ablation is increasingly used to treat AF, since recent trials of pharmacological therapy for AF have been disappointing. Ablation has been shown to improve maintenance of sinus rhythm compared to pharmacological therapy in many multicenter trials, although success rates remain suboptimal. This review will discuss several trends in the field of catheter ablation, including studies to advance our understanding of AF mechanisms in different patient populations, innovations in detecting and classifying AF, use of this information to improve strategies for ablation, technical innovations that have improved the ease and safety of ablation, and novel approaches to surgical therapy and imaging. These trends are likely to further improve results from AF ablation in coming years as it becomes an increasingly important therapeutic option for many patients.

Race- and sex-related differences in care for patients newly diagnosed with atrial fibrillation

BACKGROUND

Atrial fibrillation (AF) is associated with an increased risk of stroke and death. Uniform utilization of appropriate therapies for AF may help reduce those risks.

OBJECTIVE

We sought to determine whether significant race and sex differences exist in the treatment of newly diagnosed AF in Medicare beneficiaries.

METHODS

We used administrative encounter data for Medicare beneficiaries to identify patients with newly diagnosed AF during 2010-2011. Services received after initial AF diagnosis were cataloged, including visits with a cardiologist or electrophysiologist, catheter ablation procedures, and use of oral anticoagulants, rate control agents, and antiarrhythmic drugs.

RESULTS

Overall, 517,941 patients met study criteria, of whom 452,986 (87%) were white, 36,425 (7%) black, and 28,530 (6%) Hispanic. Male patients comprised 209,788 (41%) of the cohort. In multivariate analysis, there were statistically significant differences in the use of AF-related services by both race and sex, with white patients and male patients receiving the most care. The most notable disparities were for catheter ablation (Hispanic vs white: adjusted hazard ratio [AHR] 0.70; 95% confidence interval [CI] 0.63-0.79; P < .001; female vs male: AHR 0.65; 95% CI 0.63-0.68; P < .001) and receipt of oral anticoagulation (black vs white: AHR 0.94; 95% CI 0.92-0.95; P < .001; Hispanic vs white: AHR 0.94; 95% CI 0.93-0.97; P < .001; female vs male: AHR 0.93; 95% CI 0.93-0.94; P < .001).

CONCLUSION

Race and sex appear to have a significant effect on the health care provided to this cohort of Medicare beneficiaries diagnosed with AF. Possible explanations include racial differences in access, patient preferences, treatment bias, and unmeasured clinical characteristics.

Management of atrial fibrillation

Atrial fibrillation is a very common clinical problem with a high prevalence that is expected to rise over time because of increasing risk factors (eg, age, obesity, hypertension). This high prevalence is also associated with high cost, because atrial fibrillation represents about 1% of overall health care spending. The management of atrial fibrillation involves multiple facets: (1) management of underlying disease if present and the management of atrial fibrillation risk factors, (2) prevention of thromboembolism, (3) control of the ventricular rate during atrial fibrillation, and (4) restoration and maintenance of normal sinus rhythm.

Phased RF Ablation: Results and Concerns

Treatment of atrial fibrillation (AF) with catheter ablation has proven to be a safe and effective treatment modality which is offered to an increasing number of patients in many centers. Pulmonary vein isolation (PVI) is an established cornerstone of AF ablation strategies. Athough the isolation of the pulmonary veins (PVs) with irrigated focal radiofrequency (RF) catheters using a point-by-point method is considered as the gold standard, it can be challenging to create contiguous lesions, time consuming, and require advanced three dimensional (3D) mapping and navigational systems. The phased RF ablation system was designed to address many of these challenges associated with conventional focal RF ablation. In this review, we describe the main features of phased RF ablation and summarize the data available on clinical outcome with this technology.

Acute and Long-Term Outcomes of Catheter Ablation of Atrial Fibrillation Using the Second-Generation Cryoballoon versus Open-Irrigated Radiofrequency: A Multicenter Experience

INTRODUCTION

There are limited comparative data on catheter ablation of atrial fibrillation (CAAF) using the second-generation cryoballoon (CB-2) versus point-by-point radiofrequency (RF). This study examines the acute/long-term CAAF outcomes using these 2 strategies.

METHODS AND RESULTS

In this multicenter, retrospective, nonrandomized analysis, procedural and clinical outcomes of 1,196 patients (76% with paroxysmal AF) undergoing CAAF using CB-2 (n = 773) and open-irrigated, non-force sensing RF (n = 423) were evaluated. Pulmonary vein isolation was achieved in 98% with CB-2 and 99% with RF (P = 0.168). CB-2 was associated with shorter ablation time (40 ± 14 min vs. 66 ± 26 min; P < 0.001) and procedure time (145 ± 49 minutes vs. 188 ± 42 minutes; P < 0.001), but greater fluoroscopic utilization (29 ± 13 minutes vs. 23 ± 14 minutes; P < 0.001). While transient (7.6% vs. 0%; P < 0.001) and persistent (1.2% vs. 0%; P = 0.026) phrenic nerve palsy occurred exclusively with CB-2, other adverse event rates were similar between CB-2 (1.6%) and RF (2.6%); P = 0.207. However, freedom from AF/atrial flutter/tachycardia at 12 months following a single procedure without antiarrhythmic therapy was greater with CB-2 (76.6%) versus RF (60.4%); P < 0.001. While this difference was evident in patients with paroxysmal AF (P < 0.001), it did not reach significance in those with persistent AF (P = 0.089). Additionally, CB-2 was associated with reduced long-term need for antiarrhythmic therapy (16.7% vs. 22.0%; P = 0.024) and repeat ablations (14.6% vs. 24.1%; P < 0.001).

CONCLUSION

In this multicenter, retrospective, nonrandomized study, CAAF using CB-2 coupled with RF as occasionally required was associated with greater freedom from atrial arrhythmias at 12 months following a single procedure without antiarrhythmic therapy when compared to open-irrigated, non-force sensing RF, alone.

Effect of catheter ablation versus antiarrhythmic drugs on atrial fibrillation: A meta-analysis of randomized controlled trials

The aim of the present study was to compare the health outcomes of catheter ablation therapy against those of antiarrhythmic drugs (AADs) in the management of atrial fibrillation (AF). The effects of catheter ablation and AADs on a number of parameters were compared, including AF recurrence, all-cause mortality, stroke/transient ischemic attack (TIA) and quality of life (QoL). A systematic literature search of PubMed, Embase and the Cochrane Central Register of Controlled Trials was conducted to obtain relevant randomized controlled trials. The relative risks (RRs) and 95% confidence intervals (CIs) of AF recurrence, all-cause mortality and stroke/TIA between catheter ablation and AADs were subsequently calculated. Weighted mean differences (WMDs) and 95% CIs were used to evaluate the QoL between the two therapy groups. In total, 11 randomized trials, which included 1,763 AF patients, were eligible for the meta-analysis. Overall, the results indicated that catheter ablation produces superior outcomes compared with AADs in reducing AF recurrence (RR, 0.47; 95% CI, 0.38-0.58; P<0.001) and improving the QoL (physical component summary: WMD, 2.23; 95% CI, 0.24-4.21; P=0.03; mental component summary: WMD, 2.69; 95% CI, 0.04-5.35; P=0.05). However, no statistically significant difference was identified between the two groups with regard to the incidence of all-cause mortality (RR, 0.87; 95% CI, 0.37-2.06; P=0.76) and stroke/TIA (RR, 1.83; 95% CI, 0.73-4.55; P=0.20). In summary, catheter ablation was demonstrated to markedly reduce AF recurrence and improve QoL when compared with AAD therapy. However, the incidence rates of all-cause mortality and stroke/TIA were comparable between catheter ablation and AAD therapy.

Role of Rotors in the Ablative Therapy of Persistent Atrial Fibrillation

Atrial fibrillation (AF) ablation is increasingly used to maintain sinus rhythm yet its results are sub-optimal, especially in patients with persistent AF or prior unsuccessful procedures. Attempts at improvement have often targeted substrates that sustain AF after it is triggered, yet those mechanisms are debated. Many studies now challenge the concept that AF is driven by self-sustaining disordered wavelets, showing instead that localised drivers (rotors) may drive disorder via a process known as fibrillatory conduction. Novel mapping using wide-area recordings, physiological filtering and phase analysis demonstrates rotors in human AF. Contact mapping with focal impulse and rotor modulation (FIRM) shows that localised ablation at sources can improve procedural success in many populations on long-term follow up and some newer approaches to rotor mapping are qualitatively similar. This review critically evaluates the data on rotor mapping and ablation, which advances our conceptual understanding of AF and holds the promise of substantially improving ablative outcomes in patients with persistent AF.

Approaches to catheter ablation for persistent atrial fibrillation

BACKGROUND

Catheter ablation is less successful for persistent atrial fibrillation than for paroxysmal atrial fibrillation. Guidelines suggest that adjuvant substrate modification in addition to pulmonary-vein isolation is required in persistent atrial fibrillation.

METHODS

We randomly assigned 589 patients with persistent atrial fibrillation in a 1:4:4 ratio to ablation with pulmonary-vein isolation alone (67 patients), pulmonary-vein isolation plus ablation of electrograms showing complex fractionated activity (263 patients), or pulmonary-vein isolation plus additional linear ablation across the left atrial roof and mitral valve isthmus (259 patients). The duration of follow-up was 18 months. The primary end point was freedom from any documented recurrence of atrial fibrillation lasting longer than 30 seconds after a single ablation procedure.

RESULTS

Procedure time was significantly shorter for pulmonary-vein isolation alone than for the other two procedures (P<0.001). After 18 months, 59% of patients assigned to pulmonary-vein isolation alone were free from recurrent atrial fibrillation, as compared with 49% of patients assigned to pulmonary-vein isolation plus complex electrogram ablation and 46% of patients assigned to pulmonary-vein isolation plus linear ablation (P=0.15). There were also no significant differences among the three groups for the secondary end points, including freedom from atrial fibrillation after two ablation procedures and freedom from any atrial arrhythmia. Complications included tamponade (three patients), stroke or transient ischemic attack (three patients), and atrioesophageal fistula (one patient).

CONCLUSIONS

Among patients with persistent atrial fibrillation, we found no reduction in the rate of recurrent atrial fibrillation when either linear ablation or ablation of complex fractionated electrograms was performed in addition to pulmonary-vein isolation. (Funded by St. Jude Medical; ClinicalTrials.gov number, NCT01203748.).

New Mechanism-based Approaches to Ablating Persistent AF: Will Drug Therapy Soon Be Obsolete?

Persistent atrial fibrillation (AF) represents a major public health and medical challenge. The progressive nature of the disease, high morbidity, and increasing health-economic costs ensure that it remains at the forefront of novel research into mechanisms and potential therapies. These are largely divided into pharmacological (drugs) and electrical (ablation) with patients often going from former to latter. AF ablation has improved sufficiently to be offered as first line for paroxysmal AF, but whether drug therapy will or be relegated. In this review, we shall outline the progress in mechanistic understanding of AF that may allow results from ablation to diverge dramatically from drug therapy and identify populations in whom drug therapy may become less relevant. We end by looking ahead to future developments that we hope will spur on therapeutic efficacy in both fields.

Catheter Ablation for Atrial Fibrillation: A Review of the Literature

Atrial fibrillation (AF) is the most frequent arrhythmia seen in clinical practice. The incidence of persistent and permanent AF will likely continue to increase as the population ages and as patients with structural heart disease live longer. Until recently, antiarrhythmic medications have been the only commonly employed treatment for maintaining sinus rhythm. However, antiarrhythmic medications have a modest long-term efficacy and the potential for serious side effects. Radiofrequency (RF) catheter ablation is now emerging as a viable alternative to antiarrhythmic medications in maintaining sinus rhythm in patients with AF. A number of different ablation strategies have been used including pulmonary vein isolation, targeting of fractionated electrograms, compartmentalising the atria with linear lesions and various combinations and modifications of these lesion sets. The variation in success within and between techniques suggests that the optimal ablation technique for AF is unclear. The general consensus for patients with paroxysmal atrial fibrillation is to achieve electrical isolation of the pulmonary veins (PVs). In patients with non-paroxysmal AF, PV isolation alone appears to be insufficient. In addition, the structural and electrophysiological changes that have typically occurred at the advanced stage of AF lend greater importance to the identification and ablation of atrial myocardial substrate-driven “sources”. Further efforts are needed to develop better techniques and tools to safely, effectively, and permanently isolate the pulmonary veins, to identify which sites are critical to the maintenance of AF, and to create durable lesions to interrupt intra-arterial reentry. In this review, the rationale and outcomes of rhythm management with drugs and ablation strategies targeting various mechanisms of AF based on our current understanding are discussed.

Biomarkers in electrophysiology: role in arrhythmias and resynchronization therapy

Circulating biomarkers related to inflammation, neurohormones, myocardial stress, and necrosis have been associated with commonly encountered arrhythmic disorders such as atrial fibrillation (AF) and more malignant processes including ventricular arrhythmias (VA) and sudden cardiac death (SCD). Both direct and indirect biomarkers implicated in the heart failure cascade have potential prognostic value in patients undergoing cardiac resynchronization therapy (CRT). This review will focus on the role of biomarkers in AF, history of SCD, and CRT with an emphasis to improve clinical risk assessment for arrhythmias and patient selection for device therapy. Notably, information obtained from biomarkers may supplement traditional diagnostic and imaging techniques, thus providing an additional benefit in the management of patients.

Adjunct ablation strategies for persistent atrial fibrillation-beyond pulmonary vein isolation

Atrial fibrillation (AF) is the most common sustained arrhythmia. Recent guidelines recommend pulmonary vein isolation (PVI) as the main procedural endpoint to control recurrent AF in symptomatic patients resistant to antiarrhythmic drugs. The efficacy of such procedure is higher in paroxysmal AF while is still unsatisfactory in persistent and long-standing persistent AF. This review will summarize the state-of-the-art of AF ablation techniques in patients with persistent AF, discussing the evidence underlying different approaches with a particular focus on adjunctive ablation strategies beyond PVI including linear ablation, ablation of complex fractionated atrial electrograms (CFAE), ablation of ganglionated plexi, dominant frequency, rotors and other anatomical sites frequently involved in AF triggers.

Hybrid approaches in atrial fibrillation ablation: why, where and who?

Hybrid strategies involving surgical and catheter ablation of atrial fibrillation (AF) are rapidly evolving. Hybrid techniques may improve procedural success and minimize risks by combining the strengths and minimizing limitations of either surgical or catheter ablation alone. Further study, including randomized controlled trials, will be necessary to determine the optimal approach to hybrid ablation.

Is pulmonary vein isolation still the cornerstone in atrial fibrillation ablation?

Radiofrequency catheter ablation for atrial fibrillation (AF) has become a frequently used therapy after failure of at least one antiarrhythmic drug. The cornerstone of AF ablation has been durable pulmonary vein isolation. However, understanding the positive and negative outcomes of catheter ablation of AF is severely limited by diverse ablation methodologies that do not seem to result in durable pulmonary vein isolation. Without durable pulmonary isolation ablation, it is unclear if ablation strategies need to be modified to include extrapulmonary vein ablation targets in combination with pulmonary vein isolation or alone to improve long-term procedural success rates. The marked discrepancy between AF ablation procedure success rates and actual long-term pulmonary vein isolation rates does suggest that targeting other mechanisms can be considered to achieve similar or better results when compared to pulmonary vein isolation alone.

The role of rotors in atrial fibrillation

Despite significant advances in our understanding of atrial fibrillation (AF) mechanisms in the last 15 years, ablation outcomes remain suboptimal. A potential reason is that many ablation techniques focus on anatomic, rather than patient-specific functional targets for ablation. Panoramic contact mapping, incorporating phase analysis, repolarization and conduction dynamics, and oscillations in AF rate, overcomes many prior difficulties with mapping AF. This approach provides evidence that the mechanisms sustaining human AF are deterministic, largely due to stable electrical rotors and focal sources in either atrium. Ablation of such sources (Focal Impulse and Rotor Modulation: FIRM ablation) has been shown to improve ablation outcome compared with conventional ablation alone; independent laboratories directly targeting stable rotors have shown similar results. Clinical trials examining the role of stand-alone FIRM ablation are in progress. Looking forward, translating insights from patient-specific mapping to evidence-based guidelines and clinical practice is the next challenge in improving patient outcomes in AF management.

Risk of stroke after catheter ablation versus cardioversion for atrial fibrillation: A propensity-matched study of 24,244 patients

BACKGROUND

Stroke is the major cause of morbidity and mortality related to atrial fibrillation (AF). Catheter ablation for AF is effective in reducing AF burden, but its impact on long-term stroke risk is unknown.

OBJECTIVE

We sought to evaluate the periprocedural and long-term stroke risk after catheter ablation or cardioversion for AF.

METHODS

This retrospective, propensity-matched study using a national administrative claims database identified patients with AF who underwent catheter ablation and a comparison group (matched on age, sex, year of treatment, CHA2DS2-Vasc score, and Charlson index) who underwent cardioversion between 2005 and 2012. The primary end points were (1) time to first ischemic or hemorrhagic stroke or transient ischemic attack (TIA) and (2) time to first ischemic or hemorrhagic stroke excluding TIA. We compared periprocedural incident stroke (within 30 days of ablation or cardioversion) as well as total strokes between the 2 groups.

RESULTS

A total of 24,244 patients (12,122 patients undergoing ablation and 12,122 patients undergoing cardioversion) were included in the analysis. Incident periprocedural stroke or TIA occurred in 0.5% of the ablation group and 0.3% of the cardioversion group (P = .04). There was a significant initial risk of stroke/TIA with ablation within the first 30 days (rate ratio 1.53; P = .05). After 30 days, this risk was significantly lower in the ablation group (rate ratio 0.78; P = .03).

CONCLUSION

In patients with AF, there is a small periprocedural stroke risk with ablation in comparison to cardioversion. However, over longer-term follow-up, ablation is associated with a slightly lower rate of stroke.

Catheter ablation for asymptomatic atrial fibrillation?

Ablation therapy for atrial fibrillation (AF) has been shown to be more efficient than medical treatment alone. Long-term success of AF ablation is still around 50% after one ablation and higher after two, with a substantial amount of asymptomatic recurrences in formerly symptomatic patients. Given the lack of evidence for superiority of rhythm control over rate control in terms of stroke reduction and mortality, AF ablation remains a treatment for symptom reduction only, although ablation has never been a part of these studies. There is early evidence that ablation could decrease the long-term risk of stroke; however, prospective studies are needed to assess whether this is the case and how patients with a successful ablation can be identified. If AF ablation can be shown to improve long-term morbidity, it could also become a reasonable treatment for patients with asymptomatic AF.

Assessment and impact of cardiac fibrosis on atrial fibrillation

Fibrosis is an essential component of structural remodeling that accompanies different cardiovascular disease conditions. In cardiac arrhythmias, fibrosis plays an important role in creating the necessary substrate for these arrhythmias to persist. Non-invasive evaluation of the arrhythmia substrate has seen significant advancements in the past several years. Cardiac MRI characterizes tissue changes including fibrosis and scarring and has seen its role expand significantly in cardiac electrophysiology. We have used late-gadolinium enhancement MRI (LGE-MRI) to study tissue changes in the left atrium of patients with atrial fibrillation (AF) and demonstrated its utility in identifying poor responders to catheter ablation, as well as its association with stroke risk and significant sinus node dysfunction. Following ablation, we also studied atrial scarring and demonstrated the utility of scar imaging in guiding repeat ablation procedures.

The ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em) predicts improvement in left ventricular systolic and diastolic function 1 year after catheter ablation for atrial fibrillation

AIMS

Successful rhythm control after atrial fibrillation catheter ablation is known to induce left atrial reverse remodelling and improve left ventricular (LV) function. We explored the clinical factors affecting LV systolic and diastolic function 1-year after catheter ablation for atrial fibrillation.

METHODS AND RESULTS

We compared pre-procedural and 1-year follow-up echocardiograms in 521 patients with atrial fibrillation who underwent catheter ablation. Left ventricular systolic function was estimated by the ejection fraction (EF); diastolic function was estimated by the ratio of early transmitral flow velocity (E) to early mitral annular velocity (Em). (i) Catheter ablation of atrial fibrillation significantly reduced left atrium volume index (P < 0.001) and improved LV EF both in patients with recurrent atrial fibrillation (n = 133, P = 0.008) and those without recurrence (n = 388, P < 0.001). (ii) Follow-up EF was significantly improved in patients with baseline E/Em < 15 (n = 454, P < 0.001), whereas E/Em was significantly reduced in patients with pre-procedural E/Em ≥ 15 (n = 67, P = 0.008). (iii) Baseline E/Em < 15 (β = -3.854, 95% CI -5.99 to -1.72, P < 0.001), baseline EF <50% (β = 10.586, 95% CI 7.55 to 13.63, P < 0.001), and female (β = -1.726, 95% CI -3.36 to -0.10, P = 0.038) were independently associated with improved EF. Baseline E/Em ≥ 15 (β = 4.896, 95% CI 3.45 to 6.34, P < 0.001) and younger age (β = -0.066, 95% CI -0.11 to -0.02, P = 0.003) were independent factors associated with improved E/Em.

CONCLUSION

Pre-procedural E/Em predicted improvement in LV systolic and diastolic functions 1 year after catheter ablation for atrial fibrillation. Low baseline E/Em was independently associated with improved EF, while high E/Em predicted improvement in LV diastolic function.

The association of left atrial low-voltage regions on electroanatomic mapping with low attenuation regions on cardiac computed tomography perfusion imaging in patients with atrial fibrillation

BACKGROUND

Previous studies have shown that contrast-enhanced multidetector computed tomography (CE-MDCT) could identify ventricular fibrosis after myocardial infarction. However, whether CE-MDCT can characterize atrial low-voltage regions remains unknown.

OBJECTIVE

The purpose of this study was to examine the association of CE-MDCT image attenuation with left atrial (LA) low bipolar voltage regions in patients undergoing repeat ablation for atrial fibrillation recurrence.

METHODS

We enrolled 20 patients undergoing repeat ablation for atrial fibrillation recurrence. All patients underwent preprocedural 3-dimensional CE-MDCT of the LA, followed by voltage mapping (>100 points) of the LA during the ablation procedure. Epicardial and endocardial contours were manually drawn around LA myocardium on multiplanar CE-MDCT axial images. Segmented 3-dimensional images of the LA myocardium were reconstructed. Electroanatomic map points were retrospectively registered to the corresponding CE-MDCT images.

RESULTS

A total of 2028 electroanatomic map points obtained in sinus rhythm from the LA endocardium were registered to the segmented LA wall CE-MDCT images. In a linear mixed model, each unit increase in the local image attenuation ratio was associated with 25.2% increase in log bipolar voltage (P = .046) after adjusting for age, sex, body mass index, and LA volume, as well as clustering of data by patient and LA regions.

CONCLUSION

We demonstrate that the image attenuation ratio derived from CE-MDCT is associated with LA bipolar voltage. The potential ability to image fibrosis via CE-MDCT may provide a useful alternative in patients with contraindications to magnetic resonance imaging.

Rate Control Strategy Elevated To Primary Treatment For Atrial Fibrillation: Has The Last Word Already Been Spoken?

In the last decade, we were able to see the light shed by several trials and observational studies that dealt with the appropriate manner of treating patients with atrial fibrillation (AF). Recently the AF management by cardiologists has become more aggressive, in part because of an improved comprehension of this rhythm disturbance, as well as, the availability of new treatment strategies. Increasing awareness of AF as a disease rather than as an acceptable alternative to sinus rhythm has led to search for clear arguments to support a certain strategy as a gold standard. In this respect, the decision of whether to restore sinus rhythm, or to control the ventricular rate and allow AF to persist is of critical importance. The results of randomized, controlled trials addressing this matter shed some light on the proper way of treatment for these AF patients. The AFFIRM and RACE trials and their respective sub-studies showed surprising results. The vast majority of physicians were surprised to learn that the rate control strategy was elevated to the position of primary treatment for the AF management instead of the all-time recognized rhythm control approach to restoration and maintenance of sinus rhythm. The use of anticoagulants in the trials was different in the treatment strategies. There was a greater anticoagulant use in the rate control arm because of the belief that anticoagulation can be discontinued in the rhythm control arm when sinus rhythm was restored and maintained for one month. On the other hand, only pharmacological agents were used to maintain sinus rhythm in those trials, however, there is increasing evidence that AF ablation can restore and maintain sinus rhythm in a great proportion of patients. Indeed, there are some limitations and several interesting aspects of these trials and other studies that will be discussed. The last word has not been spoken yet.

Catheter ablation versus anti-arrhythmic drug therapy for the management of a trial fibrillation: a meta-analysis

PURPOSES

The current study was a meta-analysis designed to compare the therapeutic efficacy and safety of catheter ablation with those of anti-arrhythmic drugs, over the short and long term.

METHODS

Comparative studies (randomized controlled trials) of catheter ablation vs. anti-arrhythmic drugs for the treatment of AF were retrieved from MEDLINE and EM BASE. The primary (no recurrence of AF) and secondary (major adverse events) outcomes were compared by meta-analysis, with sub-group analysis of short-term (1 year or less) and long-term (>1 year) effects.

RESULTS

Of the 223 studies originally identified, 214 were excluded (duplication, non-randomized design, lack of relevance or lack of usable data). Compared with anti-arrhythmic drug therapy, catheter ablation was associated with superior efficacy (odds ratio [OR], 9.41; 95 % confidence interval [95 % CI], 5.00-17.71; P < 0.01). Treatment success was higher for catheter ablation both in the short term (OR, 10.84; 95 % CI, 5.83-20.16; P < 0.001) and long term (OR, 7.65; 95 % CI, 1.97-29.73; P = 0.03). There was a trend toward a lower incidence of adverse events in the catheter ablation group (OR, 2.19; 95 % CI, 0.99-4.85), but this did not reach statistical significance (P = 0.05).

CONCLUSION

Compared with anti-arrhythmic drugs, management of AF with catheter ablation showed superior efficacy in the short term that was maintained over the longer term.

Not too big, not too small: a goldilocks approach to sample size selection

We present a Bayesian adaptive design for a confirmatory trial to select a trial's sample size based on accumulating data. During accrual, frequent sample size selection analyses are made and predictive probabilities are used to determine whether the current sample size is sufficient or whether continuing accrual would be futile. The algorithm explicitly accounts for complete follow-up of all patients before the primary analysis is conducted. We refer to this as a Goldilocks trial design, as it is constantly asking the question, "Is the sample size too big, too small, or just right?" We describe the adaptive sample size algorithm, describe how the design parameters should be chosen, and show examples for dichotomous and time-to-event endpoints.

Risk factors for atrial fibrillation recurrence: a literature review

Atrial fibrillation is the most common arrhythmia managed in clinical practice and it is associated with an increased risk of mortality, stroke and peripheral embolism. Unfortunately, the incidence of atrial fibrillation recurrence ranges from 40 to 50%, despite the attempts of electrical cardioversion and the administration of antiarrhythmic drugs. In this review, the literature data about predictors of atrial fibrillation recurrence are highlighted, with special regard to clinical, therapeutic, biochemical, ECG and echocardiographic parameters after electrical cardioversion and ablation. Identifying predictors of success in maintaining sinus rhythm after cardioversion or ablation may allow a better selection of patients to undergo these procedures. The aim is to reduce healthcare costs and avoid exposing patients to unnecessary procedures and related complications. Recurrent atrial fibrillation depends on a combination of several parameters and each patient should be individually assessed for such a risk of recurrence.

Evaluating the Cost-effectiveness of Catheter Ablation of Atrial Fibrillation

Atrial fibrillation (AF) is one of the most common cardiac conditions treated in primary care and specialty cardiology settings, and is associated with considerable morbidity, mortality and cost. Catheter ablation, typically by electrically isolating the pulmonary veins and surrounding tissue, is more effective at maintaining sinus rhythm than conventional antiarrhythmic drug therapy and is now recommended as first-line therapy. From a value standpoint, the cost-effectiveness of ablation must incorporate the upfront procedural costs and risks with the benefits of longer term improvements in quality of life (QOL) and healthcare utilisation. Here, we present a primer on cost-effectiveness analysis (CEA), review the data on cost-effectiveness of AF ablation and outline key areas for further investigation.

Rationale and Design of FIRE AND ICE: A multicenter randomized trial comparing efficacy and safety of pulmonary vein isolation using a cryoballoon versus radiofrequency ablation with 3D-reconstruction

BACKGROUND

Atrial fibrillation (AF) is the most common sustained cardiac arrhythmia imposing substantial morbidity and mortality. Catheter-based pulmonary vein isolation (PVI) using radiofrequency current (RFC) has become a standard treatment for drug-resistant and symptomatic paroxysmal AF (PAF). In recent years, the cryoballoon-based technique is increasingly used as a promising alternative with a short learning curve.

METHODS

The FIRE AND ICE trial is a prospective, randomized, controlled, open, blinded outcome assessment, noninferiority trial comparing cryoballoon-, and RFC-based PVI. Patients with drug-resistant PAF will be randomized in a 1:1 matrix in multiple European centers. The primary hypothesis is that cryoballoon ablation is not inferior to RFC ablation using 3-dimensional mapping with respect to clinical efficacy. The primary endpoint is defined as the time to first documented clinical failure, including: (1) recurrence of AF; (2) atrial flutter or atrial tachycardia; (3) prescription of class I or III antiarrhythmic drugs; or (4) re-ablation, whichever comes first, following a blanking period of 3 months after the index ablation procedure. The primary safety endpoint is a composite of death, stroke/transient ischemic attack, cardiac arrhythmias (apart from AF recurrence) causally related to the therapeutic intervention, and procedure-related serious adverse events.

CONCLUSION

The FIRE AND ICE trial compares 2 different technologies to perform catheter ablation of PAF with respect to efficacy and safety. It aims at providing objective data to guide selection and usage of ablation catheters in the treatment of AF.

Paroxysmal AF catheter ablation with a contact force sensing catheter: results of the prospective, multicenter SMART-AF trial

BACKGROUND

Catheter ablation is important for treatment of paroxysmal atrial fibrillation (PAF). Limited animal and human studies suggest a correlation between electrode-tissue contact and radiofrequency lesion generation.

OBJECTIVES

The study sought to assess the safety and effectiveness of an irrigated, contact force (CF)-sensing catheter in the treatment of drug refractory symptomatic PAF.

METHODS

A prospective, multicenter, nonrandomized study was conducted. Enrollment criteria included: ≥3 symptomatic episodes of PAF within 6 months of enrollment and failure of ≥1 antiarrhythmic drug (Class I to IV). Ablation included pulmonary vein isolation with confirmed entrance block as procedural endpoint.

RESULTS

A total of 172 patients were enrolled at 21 sites, where 161 patients had a study catheter inserted and 160 patients underwent radiofrequency application. Procedural-related serious adverse events occurring within 7 days of the procedure included tamponade (n = 4), pericarditis (n = 3), heart block (n = 1, prior to radiofrequency application), and vascular access complications (n = 4). By Kaplan-Meier analyses, 12-month freedom from atrial fibrillation/atrial flutter/atrial tachycardia recurrence was 72.5%. The average CF per procedure was 17.9 ± 9.4 g. When the CF employed was between investigator selected working ranges ≥80% of the time during therapy, outcomes were 4.25 times more likely to be successful (p = 0.0054; 95% confidence interval: 1.53 to 11.79).

CONCLUSIONS

The SMART-AF trial demonstrated that this irrigated CF-sensing catheter is safe and effective for the treatment of drug refractory symptomatic PAF, with no unanticipated device-related adverse events. The increased percent of time within investigator-targeted CF ranges correlates with increased freedom from arrhythmia recurrence. Stable CF during radiofrequency application increases the likelihood of 12-month success. (THERMOCOOL® SMARTTOUCH® Catheter for Treatment of Symptomatic Paroxysmal Atrial Fibrillation; NCT01385202).

Rhythm control in heart failure patients with atrial fibrillation: contemporary challenges including the role of ablation

Because nonpharmacological interventions likely alter the risks and benefits associated with rhythm control, this paper reviews the role of current rhythm control strategies in atrial fibrillation. This report also focuses on the specific limitations of pharmacological interventions and the utility of percutaneous ablation in this growing population of patients with concomitant atrial fibrillation and heart failure.