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

Spinal cord injury neuroprotection and the promise of flexible adaptive clinical trials

Effective treatments for acute neurologic illness and injury are lacking, particularly for spinal cord injury (SCI). The very structure of clinical trials may be contributing to this because assumptions made during trial planning preclude additional learning within residual important areas of uncertainty, such as dose, timing, and duration of treatment. Adaptive clinical trials offer potential solutions to some of the factors that may be slowing the pace of discovery. Broadly defined, one can consider an adaptive clinical trial as any sort of clinical trial that makes use of information from within the trial to make decisions about how the trial is conducted going forward; however, it is important to emphasize that regardless of the degree of flexibility or complexity of an adaptive clinical trial design, the types of designs being described are only those in which all potential changes to the conduct of the trial are prospectively defined before the first patient is enrolled. Within this review, we describe the structure of flexible adaptive clinical trial designs, the process by which they are developed and conducted, and potential opportunities and drawbacks of these approaches. We must accept that there are some uncertainties that remain when both exploratory and confirmatory trials are designed. The process by which teams carefully consider which uncertainties are most important and most likely to potentially compromise the ability to detect an effective treatment can lead to trial designs that are more likely to find the right treatment for the right population of patients.

Direct or coincidental elimination of stable rotors or focal sources may explain successful atrial fibrillation ablation: on-treatment analysis of the CONFIRM trial (Conventional ablation for AF with or without focal impulse and rotor modulation)

OBJECTIVES

This study sought to determine whether ablation of recently described stable atrial fibrillation (AF) sources, either directly by Focal Impulse and Rotor Modulation (FIRM) or coincidentally when anatomic ablation passes through AF sources, may explain long-term freedom from AF.

BACKGROUND

It is unclear why conventional anatomic AF ablation can be effective in some patients yet ineffective in others with similar profiles.

METHODS

The CONFIRM (Conventional Ablation for AF With or Without Focal Impulse and Rotor Modulation) trial prospectively revealed stable AF rotors or focal sources in 98 of 101 subjects with AF at 107 consecutive ablation cases. In 1:2 fashion, subjects received targeted source ablation (FIRM) followed by conventional ablation, or conventional ablation alone. We determined whether ablation lesions on electroanatomic maps passed through AF sources on FIRM maps.

RESULTS

Subjects who completed follow-up (n = 94; 71.2% with persistent AF) showed 2.3 ± 1.1 concurrent AF rotors or focal sources that lay near pulmonary veins (22.8%), left atrial roof (16.0%), and elsewhere in the left (28.2%) and right (33.0%) atria. AF sources were ablated directly in 100% of FIRM cases and coincidentally (e.g., left atrial roof) in 45% of conventional cases (p < 0.05). During a median (interquartile range) of 273 days (138 to 636 days) after one procedure, AF was absent in 80.3% of patients if sources were ablated but in only 18.2% of patients if sources were missed (p < 0.001). Freedom from AF was highest if all sources were ablated, intermediate if some sources were ablated, and lowest if no sources were ablated (p < 0.001).

CONCLUSIONS

Elimination of stable AF rotors and focal sources may explain freedom from AF after diverse approaches to ablation. Patient-specific AF source distributions are consistent with the reported success of specific anatomic lesion sets and of widespread ablation. These results support targeting AF sources to reduce unnecessary ablation, and motivate studies on FIRM-only ablation.

Cost-Effectiveness of Atrial Fibrillation Ablation

Atrial fibrillation (AF) is a frequently encountered rhythm disorder, characterized by high recurrence rate, frequent hospitalizations, reduced quality-of-life and increased the risk of mortality, heart failure and stroke. Along with these clinical complications this type of arrhythmia is the major driver of health-related expenditures. Radiofrequency catheter ablation (RFA) of atrial fibrillation has been shown to improve freedom from arrhythmia survival, reduce re-hospitalization rate and provide better quality-of-life as compared with rate control and rhythm control with antiarrhythmic therapy. Efficacy of AF ablation in terms of outcomes and costs has an evolving importance. In this review, we aimed to highlight current knowledge on AF ablation clinical outcomes based on results of randomized clinical trials and community-based studies, and overview how this improvement in clinical end-points affects costs for arrhythmia care and cost-effectiveness of AF ablation.

Meta-analysis of the therapeutic effects of various methods for the treatment of chronic atrial fibrillation

The aim of this study was to analyze the therapeutic effects of various methods for the treatment of chronic atrial fibrillation (AF). Randomized controlled trials (RCT) concerning drug therapy and catheter ablation for the treatment of chronic AF were retrieved. The RevMan 5.1 software package was used for the meta-analysis. A total of 20 papers were assessed in this study. The results of the analysis indicated that the success rate was lower [odds ratio (OR), 8.94; 95% confidence interval (CI), 4.70-17.02; P<0.0001] and the relapse rate was higher (OR, 0.07, 95% CI, 0.05-0.10; P<0.0001) for drug therapy compared with that for catheter ablation. With regard to different catheter ablation procedures, the success rate for pulmonary vein antrum isolation (PVAI) was lower compared with that for PVAI plus complex fractionated atrial electrogram (CFAE; OR, 0.53; 95% CI, 0.37-0.78; P=0.0001). Pulmonary vein isolation (PVI) plus left atrial ablation (LAA) had a higher success rate compared with PVI alone (OR, 2.79; 95% CI, 1.59-4.88, P=0.0003). There was not identified to be a significant difference in the success rates between PVAI and CFAE (OR, 2.05; 95% CI, 0.06-205.74; P=0.76) or between PVI and circumferential pulmonary vein isolation (CPVI; OR, 0.94; 95% CI, 0.29-3.00; P=0.91). All the funnel plots of publication bias were essentially symmetrical. In conclusion, the success rate was higher and the relapse rate was lower for catheter ablation compared with drug therapy. Among the different procedures of catheter ablation, there were no significant differences in success rate between two single procedures; however, the success rates were higher for the combined methods compared with those for the single methods.

Comparing Antiarrhythmic Drugs and Catheter Ablation for Treatment of Atrial Fibrillation

In the past years, catheter ablation has evolved into an effective treatment option for symptomatic, drug-resistant atrial fibrillation (AF) and it has recently been implemented as a primary treatment strategy for patients with paroxysmal AF. Although a significant number of studies have evaluated the potential benefits of catheter ablation compared with anti-arrhythmic drug (AAD)-therapy, to date, there are only a small number of randomised controlled trials in the literature, and several issues remain unsolved. The aim of this review is to analyze the current literature regarding this important issue and further discuss the question, whether catheter ablation may be more beneficial when compared to AAD therapy.

Novel anti-arrhythmic medications in the treatment of atrial fibrillation

Atrial fibrillation (AF) is a prevalent condition particularly amongst the elderly, which contributes to both morbidity and mortality. The burden of disease has lead to significant increases in health care utilization and cost in recent years. Treatment of Atrial fibrillation consists of either a rate or rhythm control strategy. Rhythm control is achieved using medical management and/or catheter ablation. In spite of major strides in catheter ablation, this procedure remains a second line treatment of AF. Anti-arrhythmic medications represent the main treatment modality for the maintenance of sinus rhythm. Amiodarone has been used for decades because of its efficacy and lack of pro-arrhythmia despite numerous extra-cardiac side effects. Novel agents such as Dronedarone were designed to emulate Amiodarone without the extra-cardiac side effects. Unfortunately recent trials have raised concerns for the safety of this medication in certain patients. Other agents such as Vernakalant and Ranolazine are in development that promise to be more atrial selective in their action, thereby potentially avoiding pro-arrhythmia and heart failure side effects. It remains to be seen however if one or more of these agents achieves the required high efficacy and safety threshold. This review summarizes the main anti-arrhythmic clinical trials, early phase trials involving novel agents and examines the conflicting data relating to Dronedarone.

Atrial fibrillation and heart failure in the elderly

Atrial fibrillation (AF) is a common clinical problem in elderly patients and especially in those with heart failure (HF). It is a major risk factor for serious cardiovascular events, such as stroke, HF and premature death. Both the prevalence and incidence of AF increase with age and its prevalence in the United States are estimated at more than 2.2 million, with nearly 75% of patients aged >65 years. Aging-related atrial remodeling with fibrosis, dilation and mitochondrial DNA mutations predispose elderly patients to AF. Current management options for AF, including rate control and anticoagulation therapy, can be successfully applied to the elderly population. New antiarrhythmic and anticoagulation medications such as dronedarone and dabigatran, respectively, can impact the approach to therapy in the elderly. Non-pharmacological options such as catheter-based ablation have also gained prominence and have been incorporated into the guidelines for management of AF. However, more trials in the elderly and very elderly segments are needed to clarify the safety and long-term efficacy of the new treatment options.

Influence of body mass index on recurrence and quality of life in atrial fibrillation patients after catheter ablation: a meta-analysis and systematic review

BACKGROUND

Accumulating evidence has demonstrated that overweight and obesity, expressed as high body mass index (BMI), are associated with the development of atrial fibrillation (AF) and quality of life (QoL) in AF patients. However, the role of high BMI as a risk factor for prognosis and QoL in AF patients undergoing ablation remains controversial.

HYPOTHESIS

We hypothesized that elevated BMI was correlated with AF recurrence and QoL after an ablative procedure.

METHODS

We performed a comprehensive search of PubMed, EMBASE, and the Cochrane Library. Studies were included if they investigated the association of BMI with AF recurrence and QoL after ablation.

RESULTS

Of the 151 articles identified, 12 studies that enrolled 3286 individuals met the inclusion criteria. Overall, compared with normal-BMI patients, AF recurrence occured more frequently in high-BMI patients after ablation (odds ratio: 1.32, 95% confidence interval: 1.17-1.5, P < 0.001). However, the pooled esimate of odds ratio adjusted for multiple confounders did not reach significance. The summary weighted mean difference of BMI between patients with and without recurrence was 0.43 (95% confidence interval: 0.05-0.81, P = 0.027). In addition, QoL scores were significantly lower in high-BMI than in normal-BMI patients before the ablative procedure, whereas the gap of QoL between normal-BMI and high-BMI groups was decreased at follow-up.

CONCLUSIONS

Results of this meta-analysis suggest 2 points, namely that the tight association between overweight/obesity and AF recurrence after ablation may be partly due to other concomitant conditions, and that impaired QoL in high-BMI groups is significantly improved after ablation.

Benefit of pulmonary vein isolation guided by loss of pace capture on the ablation line: results from a prospective 2-center randomized trial

OBJECTIVES

This study was conducted to determine if an additional procedural endpoint of unexcitability (UE) to pacing along the ablation line reduces recurrence of atrial fibrillation (AF) or atrial tachycardia (AT) after radiofrequency catheter ablation.

BACKGROUND

AF/AT recurrence is common after pulmonary vein isolation (PVI).

METHODS

We included 102 patients from 2 centers (age 63 ± 10 years; 33 women; left atrium 38 ± 7 mm; left ventricular ejection fraction 61 ± 6%) with symptomatic paroxysmal AF. A 3-dimensional mapping system and circumferential mapping catheter were used in all patients for PVI. In group 1 (n = 50), the procedural endpoint was bidirectional block across the ablation line. In group 2 (n = 52), additional UE to bipolar pacing at an output of 10 mA and 2-ms pulse width was required. The primary endpoint was freedom from any AF/AT (>30 s) after discontinuation of antiarrhythmic drugs.

RESULTS

Procedural endpoints were successfully achieved in all patients. Procedure duration was significantly longer in group 2 (185 ± 58 min vs. 139 ± 57 min; p < 0.001); however, fluoroscopy times were not different (23 ± 9 min vs. 23 ± 9 min; p = 0.49). After a follow-up of 12 months in all patients, 26 patients (52%) in group 1 versus 43 (82.7%) in group 2 were free from any AF/AT (p = 0.001) after a single procedure. No major complications occurred.

CONCLUSIONS

The use of pacing to ensure UE along the PVI line markedly improved near-term single-procedure success, compared with demonstration of bidirectional block alone. This additional endpoint significantly improved patient outcomes after PVI. (Unexcitability Along the Ablation as an Endpoint for Atrial Fibrillation Ablation; NCT01724437).

Treatment of obstructive sleep apnea reduces the risk of atrial fibrillation recurrence after catheter ablation

OBJECTIVES

The aim of this study was to examine the effect of continuous positive airway pressure (CPAP) therapy on atrial fibrillation (AF) recurrence in patients with obstructive sleep apnea (OSA) undergoing pulmonary vein isolation (PVI).

BACKGROUND

OSA is a predictor of AF recurrence following PVI. However, the impact of CPAP therapy on PVI outcome in patients with OSA is poorly known.

METHODS

Among 426 patients who underwent PVI between 2007 and 2010, 62 patients had a polysomnography-confirmed diagnosis of OSA. While 32 patients were "CPAP users" the remaining 30 patients were "CPAP nonusers." The recurrence of any atrial tachyarrhythmia, use of antiarrhythmic drugs, and need for repeat ablations were compared between the groups during a follow-up period of 12 months. Additionally, the outcome of patients with OSA was compared to a group of patients from the same PVI cohort without OSA.

RESULTS

CPAP therapy resulted in higher AF-free survival rate (71.9% vs. 36.7%; p = 0.01) and AF-free survival off antiarrhythmic drugs or repeat ablation following PVI (65.6% vs. 33.3%; p = 0.02). AF recurrence rate of CPAP-treated patients was similar to a group of patients without OSA (HR: 0.7, p = 0.46). AF recurrence following PVI in CPAP nonuser patients was significantly higher (HR: 2.4, p < 0.02) and similar to that of OSA patients managed medically without ablation (HR: 2.1, p = 0.68).

CONCLUSIONS

CPAP is an important therapy in OSA patients undergoing PVI that improves arrhythmia free survival. PVI offers limited value to OSA patients not treated with CPAP.

Role of Intracardiac echocardiography in Atrial Fibrillation Ablation

In the recent years, several new evidences support catheter-based ablation as a treatment modality of atrial fibrillation (AF). Based on a plenty of different applications, intracardiac echocardiography (ICE) is now a well-established technology in complex electrophysiological procedures, in particular in AF ablation. ICE contributes to improve the efficacy and safety of such procedures defining the anatomical structures involved in ablation procedures and monitoring in real time possible complications. In particular ICE allows: a correct identification of the endocardial structures; a guidance of transseptal puncture; an assessment of accurate placement of the circular mapping catheter; an indirect evaluation of evolving lesions during radiofrequency (RF) energy delivery via visualization of micro and macrobubbles tissue heating; assessment of catheter contact with cardiac tissues. Recently, also the feasibility of the integration of electroanatomical mapping (EAM) and intracardiac echocardiography has been demonstrated, combining accurate real time anatomical information with electroanatomical data. As a matter of fact, different techniques and ablation strategies have been developed throughout the years. In the setting of balloon-based ablation systems, recently adopted by an increasing number of centers, ICE might have a role in the choice of appropriate balloon size and to confirm accurate occlusion of pulmonary veins. Furthermore, in the era of minimally fluoroscopic ablation, ICE has successfully provided a contribute in reducing fluoroscopy time. The purpose of this review is to summarize the current applications of ICE in catheter based ablation strategies of atrial fibrillation, focusing-on electronically phased-array ICE.

Contemporary approach to electrical and pharmacological cardioversion of atrial fibrillation

In patients with atrial fibrillation (AF), a rhythm-control strategy may be adopted when there are unacceptable symptoms from AF, failure of rate control, and/or the presence of comorbidities, such as heart failure, that may improve with restoration of sinus rhythm. When a rhythm-control strategy is chosen and the patient is in persistent AF, cardioversion will be necessary to convert the rhythm to sinus. Patients with AF present for > 48 hours must be effectively anticoagulated both prior to and after cardioversion. With newer oral anticoagulants, achieving effective anticoagulation is faster and more reliable, with no requirement for blood test monitoring. Cardioversion can be accomplished either electrically or pharmacologically, and in some cases, electrical cardioversion may be facilitated pharmacologically. Electrical cardioversion has a higher success rate compared with pharmacological cardioversion in the short-term. Pharmacological cardioversion is usually accomplished with intravenous ibutilide, oral flecainide or propafenone, or intravenous amiodarone. Oral amiodarone and dofetilide also result in chemical cardioversion in some patients over a longer period of time. Long-term success in the maintenance of sinus rhythm post-cardioversion can be increased with the use of antiarrhythmic drugs. Alternatively, when AF is recurrent and symptomatic despite the use of antiarrhythmic drugs, catheter ablation is a reasonable option for many patients. Cardioversion may be incorporated into the management approach of persistent AF when the primary therapeutic option chosen is catheter ablation.

Current Evidence and Recommendations for Rate Control in Atrial Fibrillation

Atrial fibrillation (AF) is the most common cardiac arrhythmia encountered in clinical practice, which is associated with substantial risk of stroke and thromboembolism. As an arrhythmia that is particularly common in the elderly, it is an important contributor towards morbidity and mortality. Ventricular rate control has been a preferred and therapeutically convenient treatment strategy for the management of AF. Recent research in the field of rhythm control has led to the advent of newer antiarrhythmic drugs and catheter ablation techniques as newer therapeutic options. Currently available antiarrhythmic drugs still remain limited by their suboptimal efficacy and significant adverse effects. Catheter ablation as a newer modality to achieve sinus rhythm (SR) continues to evolve, but data on long-term outcomes on its efficacy and mortality outcomes are not yet available. Despite these current developments, rate control continues to be the front-line treatment strategy, especially in older and minimally symptomatic patients who might not tolerate the antiarrhythmic drug treatment. This review article discusses the current evidence and recommendations for ventricular rate control in the management of AF. We also highlight the considerations for rhythm control strategy in the management of patients of AF.

Management strategies in atrial fibrillation in patients with heart failure

Atrial fibrillation (AF) and heart failure (HF) frequently occur together, and their coexistence is associated with a poor prognosis. AF and HF share risk factors, but their relationship involves complex hemodynamic, neurohormonal, inflammatory, ultrastructural, and electrophysiologic processes that extend beyond epidemiological associations. The shared mechanisms underlying AF and HF have important implications for the treatment of AF in patients with HF. This article focuses on reviewing contemporary data as it pertains to AF management in patients with HF and provides insight into investigational therapies currently under development.

Cryoballoon ablation of pulmonary veins for paroxysmal atrial fibrillation: first results of the North American Arctic Front (STOP AF) pivotal trial

OBJECTIVES

This study sought to assess the safety and effectiveness of a novel cryoballoon ablation technology designed to achieve single-delivery pulmonary vein (PV) isolation.

BACKGROUND

Standard radiofrequency ablation is effective in eliminating atrial fibrillation (AF) but requires multiple lesion delivery at the risk of significant complications.

METHODS

Patients with documented symptomatic paroxysmal AF and previously failed therapy with ≥ 1 membrane active antiarrhythmic drug underwent 2:1 randomization to either cryoballoon ablation (n = 163) or drug therapy (n = 82). A 90-day blanking period allowed for optimization of antiarrhythmic drug therapy and reablation if necessary. Effectiveness of the cryoablation procedure versus drug therapy was determined at 12 months.

RESULTS

Patients had highly symptomatic AF (78% paroxysmal, 22% early persistent) and experienced failure of at least one antiarrhythmic drug. Cryoablation produced acute isolation of three or more PVs in 98.2% and all four PVs in 97.6% of patients. PVs isolation was achieved with the balloon catheter alone in 83%. At 12 months, treatment success was 69.9% (114 of 163) of cryoblation patients compared with 7.3% of antiarrhythmic drug patients (absolute difference, 62.6% [p < 0.001]). Sixty-five (79%) drug-treated patients crossed over to cryoablation during 12 months of study follow-up due to recurrent, symptomatic AF, constituting drug treatment failure. There were 7 of the resulting 228 cryoablated patients (3.1%) with a >75% reduction in PV area during 12 months of follow-up. Twenty-nine of 259 procedures (11.2%) were associated with phrenic nerve palsy as determined by radiographic screening; 25 of these had resolved by 12 months. Cryoablation patients had significantly improved symptoms at 12 months.

CONCLUSIONS

The STOP AF trial demonstrated that cryoballoon ablation is a safe and effective alternative to antiarrhythmic medication for the treatment of patients with symptomatic paroxysmal AF, for whom at least one antiarrhythmic drug has failed, with risks within accepted standards for ablation therapy. (A Clinical Study of the Arctic Front Cryoablation Balloon for the Treatment of Paroxysmal Atrial Fibrillation [Stop AF]; NCT00523978).

Electrical reconnection after pulmonary vein isolation is contingent on contact force during initial treatment: results from the EFFICAS I study

BACKGROUND

Pulmonary vein isolation is the most prevalent approach for catheter ablation of paroxysmal atrial fibrillation. Long-term success of the procedure is diminished by arrhythmia recurrences occurring predominantly because of reconnections in previously isolated pulmonary veins. The aim of the EFFICAS I multicenter study was to demonstrate the correlation between contact force (CF) parameters during initial procedure and the incidence of isolation gaps (gap) at 3-month follow-up.

METHOD AND RESULTS

A radiofrequency ablation catheter with integrated CF sensor (TactiCath, Endosense, Geneva, Switzerland) was used to perform pulmonary vein isolation in 46 patients with paroxysmal atrial fibrillation. During the ablation procedure, the operator was blinded to CF information. At follow-up, an interventional diagnostic procedure was performed to assess gap location as correlated to index procedure ablation parameters. At follow-up, 65% (26/40) of patients showed ≥1 gaps. Ablations with minimum Force-Time Integral (FTI) <400 gs showed increased likelihood for reconnection (P<0.001). Reconnection correlated strongly with minimum CF (P<0.0001) and minimum FTI (P=0.0007) at the site of gap. Gap occurrence showed a strong trend with lower average CF and average FTI. CF and FTI are generally higher on the right side, although the left anterior segment presents a unique challenge to achieve stable position with good CF.

CONCLUSIONS

Minimum CF and minimum FTI values are strong predictors of gap formation. Optimal CF parameter recommendations are a target CF of 20 g and a minimum FTI of 400 gs for each new lesion.

Left atrial volumetry from routine diagnostic work up prior to pulmonary vein ablation is a good predictor of freedom from atrial fibrillation

AIMS

This study aimed to identify whether left atrial (LA) volume assessed by multidetector computed tomography (MDCT) is related to the long-term success of pulmonary vein ablation (PVA). MDCT is used to guide PVA for the treatment of atrial fibrillation (AF). MDCT permits accurate sizing of LA dimensions.

METHODS AND RESULTS

We analysed data from 368 ablation procedures of 279 consecutive patients referred for PVA due to drug-refractory symptomatic AF (age 62 ± 10; 58% men; 71% paroxysmal AF). Prior to the procedure, all patients underwent ECG-gated 64-MDCT scan for assessment of LA and PV anatomy, LA thrombus evaluation, LA volume estimation, and electroanatomical mapping integration. Within a mean follow-up of 356 ± 128 days, 64% of the patients maintained sinus rhythm after the initial ablation, and 84% when including repeat PVA. LA diameter (P = 0.004), LA volume (P = 0.002), and type of AF (P = 0.001) were independent predictors of AF recurrence in univariate analysis. There was a relatively low correlation between the echocardiographic LA diameter and LA volume from MDCT (P = 0.01, r = 0.5). In multivariate analysis, paroxysmal AF (P < 0.006) and LA volume below the median value of 106 mL (P = 0.042) were significantly associated with the success of PVA, whereas LA diameter was not (P = 0.245). Analysing receiver-operator characteristics, the area under the curve for LA volume was 0.73 (P = 0.001) compared with 0.60 (P = 0.09) for LA diameter from echocardiography.

CONCLUSION

LA volume assessed by MDCT is a better predictor of AF recurrence after PVA than echocardiograpic LA diameter and can be derived from the pre-procedural imaging data set.

Cryoballoon ablation of paroxysmal atrial fibrillation: 5-year outcome after single procedure and predictors of success

AIMS

Long-term efficacy following cryoballoon (CB) ablation of atrial fibrillation (AF) remains unknown. This study describes 5 years follow-up results and predictors of success of CB ablation in patients with paroxysmal atrial fibrillation (PAF).

METHODS AND RESULTS

In total, 163 patients were enrolled with symptomatic, drug refractory PAF. Pulmonary vein isolation (PVI) with CB technique was performed. Primary endpoint of this consecutive single-centre study was first electrocardiogram-documented recurrence of AF, atrial tachycardia or atrial flutter (AFLAT). Five years success rate after single CB ablation was 53%. In 70% of the patients acute complete PVI was achieved with a single 28 mm balloon. The univariate predictors of AFLAT recurrence were (1) size of left atrium, with normalized left atrium (NLA) ≥10.25 [hazard ratios (HR) of 1.81, 95% confidence interval (CI): 1.28-2.56] when compared with NLA <10.25 (35% vs. 53%, P = 0.0001) and (2) renal function, with impaired glomerular filtration rate (GFR) <80 ml/min (HR of 1.26, 95% CI: 1.02-1.57) when compared with GFR ≥80 ml/min (45% vs. 53%, P = 0.041). Normalized left atrium ≥10.25 was the sole independent predictor for outcome (HR 2.11; 95% CI: 1.34-3.31; P = 0.0001).

CONCLUSIONS

Sinus rhythm can be maintained in a substantial proportion of patients with PAF even 5 years after circumferential PVI using CB ablation. The rate of decline in freedom from AFLAT was highest within the first 12 months after the index procedure. The patients with enlarged left atrium and/or impaired renal function have lower outcome.

Atrial fibrillation and stroke: the evolving role of rhythm control

OPINION STATEMENT

Atrial fibrillation (AF) remains a major risk factor for stroke. Unfortunately, clinical trials have failed to demonstrate that a strategy of rhythm control--therapy to maintain normal sinus rhythm (NSR)--reduces stroke risk. The apparent lack of benefit of rhythm control likely reflects the difficulty in maintaining NSR using currently available therapies. However, there are signals from several trials that the presence of NSR is indeed beneficial and associated with better outcomes related to stroke and mortality. Most electrophysiologists feel that as rhythm control strategies continue to improve, the crucial link between rhythm control and stroke reduction will finally be demonstrated. Therefore, AF specialists tend to be aggressive in their attempts to maintain NSR, especially in patients who have symptomatic AF. A step-wise approach from antiarrhythmic drugs to catheter ablation to cardiac surgery is generally used. In select patients, catheter ablation or cardiac surgery may supersede antiarrhythmic drugs. The choice depends on the type of AF, concurrent heart disease, drug toxicity profiles, procedural risks, and patient preferences. Regardless of strategy, given the limited effectiveness of currently available rhythm control therapies, oral anticoagulation is still recommended for stroke prophylaxis in AF patients with other stroke risk factors. Major challenges in atrial fibrillation management include selecting patients most likely to benefit from rhythm control, choosing specific antiarrhythmic drugs or procedures to achieve rhythm control, long-term monitoring to gauge the efficacy of rhythm control, and determining which (if any) patients may safely discontinue anticoagulation if long-term NSR is achieved.

An assessment of the reporting quality of randomised controlled trials relating to anti-arrhythmic agents (2002-2011)

BACKGROUND

Despite being the gold-standard for investigations, randomised controlled trials can deliver biased results if methodology is flawed. The CONSORT statements are intended to guide the reporting of trials. We assessed the reporting quality of anti-arrhythmic drug trials over the last decade.

METHODS

Medline and Embase databases were searched for anti-arrhythmic drug trials between 2002 and 2011. Results were searched by two authors and relevant papers selected. Papers were scored according to the 2001 and 2010 CONSORT statements by two reviewers and compared against surrogate markers of paper quality.

RESULTS

694 papers were retrieved. 59 papers met the inclusion criteria. The mean CONSORT 2010 score was 15.4 out of 25 (SD 3.05). The least reported items related to abstract content (0%), randomization (6.8%), and protocol referencing (8.5%). There was a significant correlation between the CONSORT 2010 score and the annual and 5-year impact factors of the publishing journal (R=0.44 and R=0.45 respectively; p<0.001 for both). No significant correlation was found between the year of publication or number of authors, and 2010 CONSORT score.

CONCLUSIONS

Although several papers gained high scores, no paper successfully met all criteria laid out in either the CONSORT 2001 or 2010 statements. Correlation between CONSORT 2010 score and impact factor lends support to this as a marker for paper quality. The lack of reporting clarity found, indicates that application of the CONSORT guidelines remains incomplete within the cardiology literature. Further work is needed collectively by trial groups, funding agencies, authors, and journals to improve reporting.

Comparison of ThermoCool® Surround Flow catheter versus ThermoCool® catheter in achieving persistent electrical isolation of pulmonary veins: a pilot study

INTRODUCTION

Aim of this study was to compare efficacy and safety of the new ThermoCool Surround Flow® catheter (SFc) versus the ThermoCool® (TCc) in achieving persistent circumferential electrical isolation of the pulmonary veins (PVs) in patients with paroxysmal atrial fibrillation (AF).

METHODS AND RESULTS

This multicenter, randomized, controlled study enrolled patients suffering from paroxysmal AF. Randomization was run in a one-to-one fashion between radiofrequency ablation by TCc or SFc. Aim of PVs ablation was documentation of electrical isolation with exit/entrance block recorded on a circular catheter. Among the 106 enrolled patients, 52 (49.0%) were randomized to TCc and 54 (51.0%) to SFc. Total volume of infused saline solution during the procedure was lower in the SFc than in TCc group (752.7 ± 268.6 mL vs 1,165.9 ± 436.2 mL, P < 0.0001). Number of identified and isolated PVs was similar in the 2 groups. Number of PVs remaining isolated 30 minutes after ablation was higher in the SFc than in TCc group (95.2% vs 90.5%, P < 0.03), mainly driven by acute ablation result in the left PVs (96.1% vs 89.7%, P < 0.04). Complications were seldom and observed only in the TCc group (0% vs 3.84%, P < 0.03). At 6-month follow-up SFc patients reported a trend toward less AF recurrences compared to those in the TCc group (22.9% vs 27.0%, P = 0.69).

CONCLUSION

PV isolation by SFc lowered the rate of left PV early reconnections and reduced the volume of infused saline solution while maintaining the safety profile of AF ablation.

Comparison of circumferential pulmonary vein isolation and antiarrhythmic drug therapy in patients with atrial fibrillation

Introduction

The aim of this study was to evaluate quality of life after circumferential pulmonary vein isolation (CPVI) compared with antiarrhythmic drug therapy (ADT) in treating atrial fibrillation (AF). CPVI is now a common therapy in AF, but few studies have focused on the effect of CPVI on quality of life.

Methods

A total of 123 AF patients were followed prospectively. Quality of life was evaluated comparing CPVI with ADT as a second-line treatment for patients with AF. The Medical Outcomes Study Short Form (SF)-36 health surveys were conducted to establish a baseline score before initiation and again at 6 months after the intervention.

Results

Mean follow-up duration was 12.7 ± 4.3 months. Of 123 patients enrolled, 66 were randomized to receive CPVI and 57 to ADT alone. At the 6-month follow-up, 13 (22.8%) patients in the ADT group and 41 (62.1%) patients in the CPVI group had no recurrence of AF. The SF-36 scales were significantly higher in the CPVI than in the ADT group, as were the physical component summary scores (269.3 ± 58.6 vs. 234.9 ± 66.9) and mental component summary scores (273.6 ± 69.4 vs. 234.1 ± 44.7). Quality of life was significantly higher in the CPVI group (except for body pain).

Conclusion

In patients with AF, CPVI has superiority over ADT with regards to the maintenance of sinus rhythm and improvements in quality of life.

Rate or rhythm control for atrial fibrillation: update and controversies

Atrial fibrillation is associated with increased mortality and considerable morbidity, including stroke, heart failure, and diminished quality of life. Despite these adverse outcomes, rhythm control has not demonstrated benefit in clinical trials. Antiarrhythmic medications, including recently developed agents, have limited efficacy in achieving durable sinus rhythm and substantial toxicity. A rate-control strategy is therefore more attractive for minimally symptomatic patients, but younger and more symptomatic patients may benefit from restoration of sinus rhythm. Catheter ablation is more effective than medications in preventing arrhythmia recurrence, avoids adverse effects associated with antiarrhythmic drugs, and should be considered early in symptomatic patients when success is likely. However, more definitive data are needed from randomized trials assessing long-term outcomes after ablation, including stroke risk and mortality. Clinical decision tools help select the appropriate management for individual patients. Lenient rate management is easy to achieve and seems reasonably safe for certain patients, although the optimum rate varies with individual comorbidities. Because safer and more effective pharmacologic and interventional therapies are now available, an individualized approach to atrial fibrillation management is essential.