Catheter ablation for AF improves global thrombotic profile and enhances fibrinolysis

Patients with atrial fibrillation (AF) are at increased risk of thrombotic events despite oral anticoagulation (OAC). Radiofrequency catheter ablation (RFCA) can restore and maintain sinus rhythm (SR) in patients with AF. To assess whether RFCA improves thrombotic status. 80 patients (71% male, 64 ± 12y) with recently diagnosed AF, on OAC and scheduled to undergo RFCA or DC cardioversion (DCCV) were recruited. Thrombotic status was assessed using the point-of-care global thrombosis test (GTT), before, and 4-6 weeks after DCCV and 3 months after RFCA. The GTT first measures the time taken for occlusive thrombus formation (occlusion time, OT), while the second phase of the test measures the time taken to spontaneously dissolve this clot through endogenous thrombolysis (lysis time, LT). 3 months after RFCA, there was a significant reduction in LT (1994s [1560; 2475] vs. 1477s [1015; 1878]) in those who maintained SR, but not in those who reverted to AF. At follow-up, LT was longer in those in AF compared to those in SR (AF 2966s [2038; 3879] vs. SR 1477s [1015; 1878]). RFCA resulted in no change in OT value, irrespective of rhythm outcome. Similarly, there was no change in OT or LT in response to DCCV, irrespective of whether SR was restored. Successful restoration and maintenance of SR following RFCA of AF is associated with improved global thrombotic status with enhanced fibrinolysis. Larger studies are required to confirm these early results and investigate whether improved thrombotic status translates into fewer thromboembolic events.

[New onset atrial fibrillation in patients with sepsis]

BACKGROUND

Atrial fibrillation is the most common new onset arrhythmia in patients hospitalized with sepsis; however, there are no specific treatment guidelines and the ideal therapeutic approaches still remain unclear.

OBJECTIVES

To begin with the current state of knowledge concerning the underling mechanisms, the incidence and prognostic impact of new onset atrial fibrillation during sepsis are presented. Then a possible therapeutic algorithm for the special situation of sepsis is derived with respect to the currently existing atrial fibrillation guidelines. Finally necessary future research topics are outlined.

MATERIAL ANS METHODS

A systematic literature search was conducted in MEDLINE. All publications (reviews and studies) relevant for the summary of the current knowledge regarding new onset atrial fibrillation in septic patients were included.

RESULTS

The underlying patchomechanism is primarily systemic inflammation. Approximately 8% of patients with sepsis and more than 20% of patients with septic shock develop new onset atrial fibrillation. The occurrence of atrial fibrillation is associated with increased morbidity and mortality. The necessity of rhythm control therapy is dependent on the hemodynamic stability. The success rate of electrical cardioversion can be increased by the administration of amiodarone. The necessity of systemic anticoagulation is based on the individual risk of thromboembolism.

CONCLUSION

Further research is needed to unveil the optimal therapeutic strategies for patients with new onset atrial fibrillation during sepsis.

Advanced interatrial block is an electrocardiographic marker for recurrence of atrial fibrillation after electrical cardioversion

BACKGROUND

Early recurrence of atrial fibrillation (AF) is common following a successful electrical cardioversion (ECV). The purpose of this study was to investigate the hypothesis that AF recurrence is related to atrial electrical inhomogeneity, which may influence the P wave characteristics.

METHODS

Two hundred ninety-one consecutive persistent AF patients who underwent ECV were enrolled, and evaluated for AF recurrences one month after the ECV. Patients with open-heart surgery, a history of catheter ablation, and an unsuccessful ECV were excluded. The P wave duration, dispersion and P wave morphology were evaluated by 12‑lead ECGs 30 min after the ECV.

RESULTS

In total, 141 patients were investigated. One month after the ECV, 60 (43%) patients maintained sinus rhythm. The advanced interatrial block (aIAB; P wave duration >120 ms and biphasic P waves in the inferior leads) (Hazard ratio [HR], 4.51; 95% confidence interval [CI] 1.45-14.01, P = 0.009), P wave dispersion (HR, 1.06; 95%CI 1.02-1.09, P = 0.001), and duration of AF per month (HR, 1.03; 95%CI 1.01-1.04, P = 0.004) were independent predictors of AF recurrence. An aIAB was not associated with structural parameters such as the left atrial volume index or right atrial area. There were no differences in the serum BNP level and frequency of administering anti-arrhythmic drugs between the patients with and without recurrence.

CONCLUSIONS

The risk of AF recurrence after the ECV can be predicted by the P wave characteristics. A longer P wave dispersion and the duration of AF also had a tendency for recurrence.

Optimal timing for cardioversion in patients with atrial fibrillation

BACKGROUND

Electrical cardioversion (CV) is essential in rhythm management of atrial fibrillation (AF). However, optimal timing of CV remains unknown.

HYPOTHESIS

Timing of CV in AF is associated with risk of adverse events.

METHODS

We analyzed the effect of AF episode duration on safety and efficacy of electrical CV in a multicenter, multicohort study exploring 4356 CVs in 2530 patients on oral anticoagulation. The composite adverse outcome included unsuccessful CV, acute arrhythmic complications, thromboembolic events, mortality, and AF recurrence within 30-day follow-up.

RESULTS

Study groups were stratified according to duration of index AF episode (<24 h, 24-48 h, 48 h-30d, and > 30d), consisting of 1767, 516, 632, and 1441 CVs, respectively. CVs were unsuccessful in 8.5% (<24 h), 5.4% (24-48 h), 11.1% (48 h-30d), and 13.9% (>30d), respectively (P < 0.01). Occurrence of thromboembolic events (0.1%), mortality (0.1%), and asystole >5 seconds (0.7%) within 30-day follow-up was infrequent and comparable in the study groups. AF recurrence within 30 days after initially successful CVs was 29.8% (<24 h), 26.5% (24-48 h), 37.3% (48 h-30d), and 30.3% (>30d), respectively (P < 0.01). Composite adverse outcome occurred in 1669 (38.4%) CVs, and index AF episode >48 hours was an independent predictor for the composite endpoint (OR: 1.49, 95% CI: 1.28-1.74, P < 0.01) in multivariate analysis.

CONCLUSIONS

Optimal timing of CV for AF showed a J-shaped curve, with fewest adverse outcomes in patients with CV performed 24 to 48 hours after onset of AF. In patients with rhythm-control strategy, delaying CV >48 hours is associated with increased risk for adverse outcomes.

[Vernakalant in hospital emergency practice: safety and effectiveness]

OBJECTIVES

To study the effectiveness and safety of vernakalant for restoration of sinus rhythm in patients with atrial fibrillation (AF) in routine hospital emergency department care, and to evaluate factors associated with a more effective response.

MATERIAL AND METHODS

Prospective multicenter cohort study enrolling consecutive patients who were administered vernakalant for medical cardioversion of AF between September 2014 through March 2016 in 5 hospitals in the Spanish autonomous community of Valencia.

RESULTS

We studied 165 cases. The median (interquartile range) was 68 years (56-77) years. Cardioversion with vernakalant was effective in 77.6% (95% CI, 71.1%-84%). The median time to conversion was 8 ( 6-12) minutes after a first dose and 34 (22-62) minutes after a second dose. A prior history of cardiac insufficiency was nonsignificantly less common in patients who converted with vernakalant (6.3%) than in those who did not (18.9%) (adjusted odds ratio [OR], 0.45 [95% CI, 0.13-1.56]; P=.208). Having no prior history of AF was nonsignificantly related to greater effectiveness (in 54.7% vs in 35.1% with prior AF). Duration less than 12 hours was significantly associated with greater effectiveness (83.6% vs 59.5%; adjusted OR, 2.76 [95% CI, 1.12-6.80]; P=.028). Adverse events were reported for 30 patients. None of the events had clinically important consequences, and in only 2 cases (1.2%) was it necessary to suspend treatment.

CONCLUSION

Vernakalant is effective and safe for restoring sinus rhythm in the hospital emergency department.

Predictors of sinus rhythm after electrical cardioversion of atrial fibrillation: results from a data mining project on the Flec-SL trial data set

Aims

Data mining is the computational process to obtain information from a data set and transform it for further use. Herein, through data mining with supportive statistical analyses, we identified and consolidated variables of the Flecainide Short-Long (Flec-SL-AFNET 3) trial dataset that are associated with the primary outcome of the trial, recurrence of persistent atrial fibrillation (AF) or death.

Methods and results

The 'Ranking Instances by Maximizing the Area under the ROC Curve' (RIMARC) algorithm was applied to build a classifier that can predict the primary outcome by using variables in the Flec-SL dataset. The primary outcome was time to persistent AF or death. The RIMARC algorithm calculated the predictive weights of each variable in the Flec-SL dataset for the primary outcome. Among the initial 21 parameters, 6 variables were identified by the RIMARC algorithm. In univariate Cox regression analysis of these variables, increased heart rate during AF and successful pharmacological conversion (PC) to sinus rhythm (SR) were found to be significant predictors. Multivariate Cox regression analysis revealed successful PC as the single relevant predictor of SR maintenance. The primary outcome risk was 3.14 times (95% CI:1.7-5.81) lower in those who had successful PC to SR than those who needed electrical cardioversion.

Conclusions

Pharmacological conversion of persistent AF with flecainide without the need for electrical cardioversion is a powerful and independent predictor of maintenance of SR. A strategy of flecainide pretreatment for 48 h prior to planned electrical cardioversion may be a useful planning of a strategy of long-term rhythm control.

[Is it worth delivering Direct-Current Counter shock to critically ill patients with supra-ventricular tachyarrhythmia?]

Supra-ventricular tachyarrhythmia and its treatment have been poorly investigated in ICU patients.

AIMS

To evaluate efficacy and safety of cardioversion for supra-ventricular tachyarrhythmia in the intensive care unit (ICU).

PATIENTS AND METHODS

Prospective inclusion of all patients who presented supra-ventricular tachyarrhythmias lasting≥30seconds in a single medico-surgical ICU, except cardiac surgery. Anti-arrhythmic drugs and/or direct-current cardioversion were administered on a liberal basis.

RESULTS

During the 15-month study period, 108/846 patients (12.8%) experienced supra-ventricular tachyarrhythmias. Anti-arrhythmic drugs were administered in 78 patients (72%); mostly amiodarone (92%), and/or magnesium (23%), resulting in an overall conversion rate of 68%. Direct-current cardioversion was used in 26 patients (24%), (24 patients received drug enhancement by anti-arrhythmic drugs) with an immediate 80.8%-success rate.

CONCLUSION

Direct-current cardioversion was associated with sustained conversion to sinus rhythm in 80.8% of ICU patients with supra-ventricular tachyarrhythmias, although most of them had already received drug enhancement.

[Biomarkers and atrial fibrillation : Prediction of recurrences and thromboembolic events after rhythm control management]

Atrial fibrillation (AF) is the most common arrhythmia in clinical praxis and is associated with an increased risk for cardio- and cerebrovascular complications leading to an increased mortality. Catheter ablation represents one of the most important and efficient therapy strategies in AF patients. Nevertheless, the high incidence of arrhythmia recurrences after catheter ablation leads to repeated procedures and higher treatment costs. Recently, several scores had been developed to predict rhythm outcomes after catheter ablation. Biomarker research is also of enormous interest. There are many clinical and blood biomarkers pathophysiologically associated with AF occurrence, progression and recurrences. These biomarkers-including different markers in blood (e. g. von Willebrand factor, D‑dimer, natriuretic peptides) or urine (proteins, epidermal grown factor receptor) but also cardiac imaging (echocardiography, computed tomography, magnetic resonance imaging)-could help to improve clinical scores and be useful for individualized AF management and optimized patients' selection for different AF treatment strategies. In this review, the role of diverse biomarkers and their predictive value related to AF-associated complications are discussed.

Association between transthoracic impedance and electrical cardioversion success with biphasic defibrillators: An analysis of 1055 shocks for atrial fibrillation and flutter

BACKGROUND

The relevance of transthoracic impedance (TTI) to electrical cardioversion (ECV) success for atrial tachyarrhythmias when using biphasic waveform defibrillators is unknown.

HYPOTHESIS

TTI is predictive of ECV success with contemporary defibrillators.

METHODS

De-identified data stored in biphasic defibrillator memory cards from ECV attempts for atrial fibrillation (AF) or atrial flutter (AFL) over a 2-year period at our center were evaluated. ECV success, defined as arrhythmia termination and ≥ 1 sinus beat, was adjudicated by 2 blinded cardiac electrophysiologists. The association between TTI and ECV success was assessed via Cochrane-Armitage trend and Spearman rank correlation tests, as well as simple and multivariable logistic regression. The influence of TTI on the number of shocks and on cumulative energy delivered per patient was also examined.

RESULTS

703 patients (593 with AF, 110 with AFL) receiving 1055 shocks were included. Last shock success was achieved in 88.0% and 98.2% of patients with AF and AFL, respectively. In patients with AF, TTI was positively associated with last shock failure (P_trend  =0.019), the need for multiple shocks (P_trend  <0.001), and cumulative energy delivered (ρ = 0.348; P < 0.001). After adjusting for first shock energy, 10-Ω increments in TTI were associated with odds ratios of 1.36 (95% CI: 1.24-1.49) and 1.22 (95% CI: 1.09-1.37) for first and last shock failure, respectively (P < 0.001 for both).

CONCLUSIONS

Although contemporary defibrillators are designed to compensate for TTI, this variable continues to be associated with ECV failure in patients with AF. Strategies to lower TTI during ECV for AF may improve procedural success.

Cardioversion of persistent atrial fibrillation is associated with a 24-hour relapse gap: Observations from prolonged postcardioversion rhythm monitoring

BACKGROUND

Many recurrences occur after electrical cardioversion (ECV) of atrial fibrillation (AF). Assessment of extent of remodeling and continuous prolonged rhythm monitoring might reveal actionable recurrence mechanisms.

HYPOTHESIS

After ECV of AF specific patterns of arrhythmia recurrence can be distinguished.

METHODS

All patients who underwent successful ECV due to persistent AF were included. Tissue velocity echocardiography during AF was performed before ECV to study atrial fibrillatory cycle length and fibrillatory velocity. After ECV, the heart rhythm of all patients was monitored 3 times daily during 4 weeks, and timing of recurrence was noted.

RESULTS

In total, 50 patients (68% male) were included; mean age was 68 ± 9 years. Median duration of the current AF episode was 102 (range, 74-152) days. Twenty-one (42%) patients showed recurrence of persistent AF. No recurrences occurred during the first 24 hours. There were no differences in clinical characteristics between patients with or without recurrence of AF. However, patients with early recurrence of AF had significantly higher precardioversion wall-motion velocity compared with patients who remained in sinus rhythm (2.8 [1.6-3.6] vs 1.4 [0.9-3.3] cm/s; P = 0.017), whereas atrial fibrillatory cycle length did not differ.

CONCLUSIONS

In this study on 50 patients successfully cardioverted for persistent AF, there was a relapse gap of ≥24 hours. This phenomenon has not been well appreciated before and offers an AF-free window of opportunity for electrocardiographically triggered cardiac imaging or complex electrophysiological procedures. Echocardiographic tissue velocity imaging may visualize atrial remodeling relevant to AF recurrence.

Cardioversion-Responsive Ventriculoatrial Shunt Malfunction Precipitated by Atrial Fibrillation

BACKGROUND

Ventriculoatrial shunts are common alternatives for patients who cannot tolerate ventriculoperitoneal shunts. The majority of ventriculoatrial shunt malfunctions are related to mechanical problems. We report an interesting case of ventriculoatrial shunt malfunction due to elevated central venous pressure from new-onset atrial fibrillation.

METHODS

After the patient was confirmed to have ventriculomegaly, he was taken to the operating room for exploration of his ventriculoatrial shunt; there were no obstructions. Subsequently, the patient was cardioverted to normal sinus rhythm for his new onset atrial fibrillation.

RESULTS

The clinical syndrome and ventriculomegaly both resolved after the patient's atrial fibrillation was corrected with chemical cardioversion.

CONCLUSIONS

The cause of this patient's VA shunt malfunction was likely associated with his new onset atrial fibrillation.

Landiolol for managing post-operative atrial fibrillation

Beta-blockers are a potential option to manage peri-operative atrial fibrillation. Landiolol is a new ultra-short beta-blocker with a half-life of only 4 minutes and very high beta-1 selectivity which has been used for treatment and prevention of atrial fibrillation in pulmonary surgery and gastro-intestinal surgery. Due to its limited negative inotropic effect and high beta-1 selectivity landiolol allows for control of heart rate with minimal impact on blood pressure. Landiolol is well tolerated by the respiratory system. Additional benefits are related to the regulation of the inflammatory response and blunting of the adrenergic pathway. There is a limited number of trials with total of 61 patients undergoing lung resection or oesophagectomy who developed post-operative atrial fibrillation and were treated with landiolol. The experience with landiolol for prevention is more documented than landiolol application for treatment of post-operative atrial fibrillation. There are 9 comparative studies with a total of 450 patients administered landiolol for prevention of post-operative atrial fibrillation. The use of low dosage (5-10mcg/kg/min) is usually sufficient to rapidly control heart rate which is associated with earlier and higher rate of conversion to sinus rhythm as compared to the controls. The excellent tolerance of landiolol at lower dosage (3-5mcg/kg/min) allows to initiate prophylactic use during surgery and postoperatively. Landiolol prophylaxis is associated with reduced incidence of post-operative atrial fibrillation without triggering adverse events related to a beta-blockade.

Effect of sinus rhythm restoration on markers of thrombin generation in atrial fibrillation

Background

Atrial fibrillation (AF) confers a hypercoagulable state; however, it is not clear whether restoration of sinus rhythm is associated with normalisation of markers of thrombogenesis. We studied the impact of sustained sinus rhythm on prothrombotic markers, and their predictive abilities in foreseeing rhythm outcome after cardioversion.

Methods

In a double blind, placebo-controlled study, 171 patients referred for electrical cardioversion of persistent AF were randomised to receive candesartan or placebo for 3-6 weeks before and 6 months after cardioversion. Endogenous thrombin potential (ETP), prothrombin fragment 1 + 2 (F1 + 2) and D-dimer were measured before cardioversion and at end of study. These markers were also measured in a reference group comprising 49 subjects without AF.

Results

The markers remained unchanged in those 28 patients who maintained sinus rhythm. Discontinuation of warfarin treatment in a subset of 13 low-risk patients in sinus rhythm was associated with significantly higher levels of D-dimer and F1 + 2 compared to the reference group; D-dimer (456 ng/mL (276, 763) vs. 279 ng/mL (192, 348), p = 0.002) and F1 + 2 (700 pmol/L (345, 845) vs. 232 pmol/L (190, 281), p < 0.001). None of the markers were associated with rhythm outcome after electrical cardioversion.

Conclusions

Sustained sinus rhythm for 6 months after cardioversion for AF had no impact on ETP, F1 + 2 or D-dimer levels. Discontinuation of warfarin in low-risk patients with sustained sinus rhythm was associated with significantly higher levels of D-dimer and F1 + 2 compared to the reference group. Our results suggest persistent hypercoagulability in AF patients despite long-term maintenance of sinus rhythm.

Trial registration

The CAPRAF study was registered at clinicaltrials.gov (NCT00130975) in August 2005.

Safety of cardioversion in atrial fibrillation lasting less than 48 h without post-procedural anticoagulation in patients at low cardioembolic risk

Currently, there is no unified consensus on short-term anticoagulation after cardioversion of atrial fibrillation lasting less than 48 h in low-cardioembolic-risk patients. The aim of this study is to evaluate the rate of transient ischemic attacks, stroke and death in this subset of patients after cardioversion without post-procedural anticoagulation. In a prospective observational study, patients with recent-onset AF undergoing cardioversion attempts in the Emergency Department were evaluated over the past 3 years. Inclusion criteria were conversion to sinus rhythm, low thromboembolic risk defined by a CHA2DS2VASc score of 0-1 points for males (0-2 points for females aged over 65 years), and hospital discharge without anticoagulant treatment. Patients with severe valvular heart disease, underlying systemic causes of AF, and those discharged with anticoagulant therapy were excluded. The main outcomes measured were TIA, stroke and death at thirty days' follow-up after discharge. During the study period, 218 successful cardioversions, obtained both electrically and pharmacologically, were performed on 157 patients. One hundred and eleven patients were males (71%), the mean age was 55.2 years (±standard deviation 10.7), 99 patients (63%) reported a CHA2DS2VASc score of 0, and the remaining 58 (37%) had a risk profile of 1 point. Of these, latter 8 were females (5%) older than 65 years (risk score 2 points). At the thirty days outcome, none of the 150 enrolled patients who completed a follow-up visit has reported TIA or stroke, nor died, in the overall 211 successful cardioversions evaluated. In our study, the rate of thromboembolic events after cardioversion of recent-onset AF of less than 48 h duration, in patients with a 0-1 CHA2DS2VASc risk profile (females 0-2), appeared to be extremely low even in absence of post-procedural anticoagulation. These findings seem to confirm data from previous studies, and suggest that routine post-procedural short-term anticoagulation may be considered as an overtreatment in this very low-risk subset of patients.

External electrical cardioversion of persistent atrial fibrillation in a patient with a Micra™ Transcatheter Pacing System

We report a case of a 85-year old woman with a preexisting Transcatheter Pacing System (TPS) (Micra™ VR, Fa. Medtronic, Inc., Minneapolis, MN, USA) undergoing several external electrical cardioversions (CV) for symptomatic persistent atrial fibrillation (persAF). Due to bradycardia in the setting of atrial fibrillation a right apical TPS implantation was performed earlier. Four weeks prior to presentation at our facility an unsuccessful CV with a maximum biphasic energy level of 360J was performed, after which amiodarone was initiated. At the time of presentation three shocks with 100 J, 200 J and 360 J were delivered without sustained restoration of a stable sinus rhythm. Patches were in an anterior-posterior position. No complications and no significant changes in device parameters in comparison to the pre-acquired values were observed. To our knowledge, this is the first case report of an external CV in a patient with a TPS. External CV in patients with a preexisting TPS seems to be safe and feasible.

Cardioversions and Transthoracic Echocardiography

Patients with atrial fibrillation and flutter routinely require transesophageal echocardiography with cardioversion. It is not uncommon to encounter patients with reduced ejection fractions, coronary artery disease, prior cardiac surgery, or obstructive sleep apnea. The anesthesiologist must carefully evaluate the patient and any available laboratory and study findings to assess for potential complications after anesthesia. Appropriate anesthetics must be chosen based on the preoperative evaluation. Additionally, because most of these cases are done without a secured airway, emergency medications and airway equipment must be readily available.

Electrical cardioversion of patients with implanted pacemaker or cardioverter-defibrillator: results of a survey of german centers and systematic review of the literature

AIMS

A relevant number of patients presenting for electrical cardioversion carry a pacemaker (PM) or ICD. Case reports suggest a potential hazard of external cardioversion/defibrillation. The incidence of shock related device complications is unknown. No guidelines or recommendations by international medical societies for a cardioversion protocol of cardiovascular implantable electronic device (CIED) patients exist. We conducted a nationwide survey to gather real-world clinical data on the current clinical approach towards these patients during electrical cardioversion and to estimate the incidence of shock-related complications.

METHODS AND RESULTS

Ninety hospitals with > 380 ECV in 2014 were identified from mandatory hospital quality reports and 60 were randomly selected. All centers were provided with a standardized questionnaire on the general proceedings and complications during electrical cardioversion of pacemaker, ICD and CRT patients (CIED patients). Thirty-two centers (53%) participated in the survey. In total, 16,554 ECV were reported (534 ± 314 per center). Biphasic cardioversion with a first shock energy of ≥ 150 J via adhesive patches in antero-posterior orientation was preferred by most centers (78%). Eleven percent (n = 1809) of pts were reported to carry a PM/ICD. The ECV protocol was heterogeneous among centers. Complications associated with electrical cardioversion were reported in 11/1809 patients (0.6%), all were transitory elevations of pacing thresholds.

CONCLUSIONS

In this nationwide snapshot survey of cardioversion procedures in Germany, approximately 11% of patients presenting for elective electrical cardioversion were pacemaker or ICD carriers. Cardioversion protocols in these patients are heterogeneous throughout centers and mostly not in accordance with recommendation of the German Cardiac Society. Complications associated with external electrical cardioversion are rare. Controlled trials and large registries are necessary to provide evidence for future recommendations.

Clinical scores for outcomes of rhythm control or arrhythmia progression in patients with atrial fibrillation: a systematic review

Patients with atrial fibrillation (AF) are commonly managed with rhythm control strategy, but the natural history of this common arrhythmia leads itself to progression from paroxysmal to persistent or permanent AF, and recurrences are evident despite rhythm control treatments using cardioversion or catheter ablation. Numerous clinical factors have been associated with outcomes of rhythm control or arrhythmia progression in patients with AF. The more common factors have been used to formulate risk stratification scores, to help predict the outcomes of rhythm control treatments or AF progression. This review article provides an overview on the published clinical risk scores related to outcomes of rhythm control strategy or AF progression.

Study on the Effect of Irbesartan on Atrial Fibrillation Recurrence in Kumamoto: Atrial Fibrillation Suppression Trial (SILK study)

BACKGROUND

Experimental studies suggest that angiotensin II-receptor blockers can influence atrial remodeling and may prevent atrial fibrillation (AF). Therefore, we hypothesized that irbesartan may prevent the recurrence of AF following either catheter ablation or electrical cardioversion of AF.

METHODS

Study on the Effect of Irbesartan on Atrial Fibrillation Recurrence in Kumamoto (SILK study) is a prospective, multicenter, randomized, and open-label comparative evaluation of the effects of irbesartan and amlodipine on AF recurrence in hypertensive patients with AF who are scheduled to undergo catheter ablation or electrical cardioversion of AF. The primary end point was either AF or atrial tachycardia (AT) recurrence. AF/AT recurrence was evaluated for 6 months using 24-h Holter electrocardiogram and portable electrocardiogram. The secondary endpoints included the change in blood pressure, the interval from the procedure to the first AF/AT recurrence, cardiovascular events, left atrial diameter (LAD), left ventricular ejection fraction (LVEF), and changes in the biomarkers [brain natriuretic polypeptide (BNP), high-sensitivity C-reactive protein (hs-CRP), urinary albumin/creatinine].

RESULTS

The study enrolled 98 patients (irbesartan; n=47, amlodipine; n=51). The recurrence of AF/AT was observed in 8 patients (17.0%) in the irbesartan group and in 10 patients (19.6%) in the amlodipine group. There was no significant difference in the AF/AT recurrence between the irbesartan and amlodipine groups. Blood pressure decreased similarly in both groups. There were no significant differences between the two groups as regards to the interval from the procedure to the first AF/AT recurrence, occurrence of cardiovascular events, changes in LAD and LVEF. BNP and urinary albumin/creatinine significantly decreased similarly in both groups, but no significant difference was found in hs-CRP between the two groups.

CONCLUSIONS

In hypertensive patients with AF, treatment with irbesartan did not have any advantage over amlodipine in the reduction of AF/AT recurrence after catheter ablation or electrical cardioversion.

Non-Vitamin K Antagonist Oral Anticoagulants for Cardioversion in Atrial Fibrillation: An Updated Meta-analysis

BACKGROUND

Non-vitamin K oral anticoagulants are now proven alternatives to vitamin K antagonists for stroke prevention in atrial fibrillation. However, there are few data on the efficacy and safety of their use for cardioversion, in which the risk of thromboembolic events is heightened.

METHODS

We performed a random-effects meta-analysis of patients undergoing both electrical and pharmacologic cardioversion for atrial fibrillation in the RE-LY, ROCKET-AF, ARISTOTLE, ENGAGE AF-TIMI 48, X-VeRT, and ENSURE-AF trials. We assessed Mantel-Haenszel pooled estimates of risk ratios (RRs) and 95% confidence intervals (CIs) for stroke/systemic embolism and major bleeding at ≤42 days of follow-up.

RESULTS

The analysis pooled 6148 patients in whom 6854 cardioversions for atrial fibrillation were performed. Compared with vitamin K antagonists, non-vitamin K antagonist oral anticoagulant therapy was associated with a similar risk of stroke/systemic embolism (RR, 0.82; 95% CI, 0.38-1.75) and major bleeding (RR, 0.98; 95% CI, 0.51-1.87). We found no significant statistical heterogeneity among studies (Cochrane Q P = .75, I² = 0% for stroke/systemic embolism; P = .54; I² = 0% for major bleeding).

CONCLUSIONS

The short-term incidence of thromboembolism and major bleeding after cardioversion on non-vitamin K antagonist oral anticoagulants was comparable to the incidence observed on dose-adjusted vitamin K antagonist therapy. Non-vitamin K antagonist oral anticoagulants are a reasonable alternative to vitamin K antagonists in patients undergoing cardioversion.

The significance of the left atrial volume index in prediction of atrial fibrillation recurrence after electrical cardioversion

Introduction: Electrical cardioversion (ECV) is a safe method for the treatment of atrial fibrillation. It seems that left atrial volume index (LAVI) could be a good marker in predicting the success of ECV. The purpose of this study is to assess of the significance of LAVI measurement before ECV in predicting the recurrence of the AF.

Methods: Fifty-one patients with AF, selected for ECV were studied in the cardiology department of Tabriz University of medical sciences. The clinical and demographic data of all the patients were obtained. Echocardiography was performed before and also three months after ECV. Patients were separated into two groups: those who maintained SR and those with relapse of AF diagnosed by clinical manifestations and electrocardiography (ECG).

Results: Sinus rhythm (SR) was maintained in 76.5 percent of the patients following the three months after ECV. The age, sex and the body mass index (BMI) were not significantly different between SR and AF groups. Two groups showed no significant differences considering pre-ECV medical history including medications and systemic diseases. The initial LAVI of SR group was 42.21±12.4 mL/m² and AF group was 96.08±52.21 mL/m², the initial LAVI was significantly different between two groups (P = 0.000). The LAVI of SR group decreased significantly (5.69±0.74 mL/m²) after three months, LAVI decreased from 42.21 ± 12.4 ml/m² to 37.51 ± 10.52 mL/m². (P = 0.000). The cut-off point of LAVI value in predicting the maintenance of SR was 55 mL/m².

Conclusion: The present study indicates that LAVI is a powerful forecaster of the recurrence of AF after ECV. The LAVI measurement could be a useful method in the selection of the patients with AF for ECV.

Findings of transoesophageal echocardiogram in appropriately anticoagulated patients with persistent atrial fibrillation prior to planned cardioversion

Background

To evaluate a diagnostic value of transoesophageal echocardiogram (TEE) in appropriately anticoagulated patients with a non-valvular atrial fibrillation (AF) and to establish possible additional indications for TEE; to evaluate the incidence of left atrial (LA) thrombi in appropriately anticoagulated patients in daily clinical practice.

Methods

This retrospective study analyses data of 432 patients who had been anticoagulated by means of oral anticoagulants (OACs) prior to planned cardioversion during the period from 2012 to 2015. Thromboembolic (TE) and bleeding risks were assessed using CHA2DS2-VASc and HAS-BLED scores. Transthoracic and transoesophageal echocardiograms were evaluated. TE complications during 30 days after discharge were assessed.

Results

432 patients were selected, aged from 22 to 89 years (mean 65.0 ±11.5), 277 (64.1%) males and 155 (35.9%) females, 306 (70.8%) on warfarin and 126 (29.2%) on non-vitamin K antagonist oral anticoagulants (NOAC). Mean CHA2DS2-VASc score was 3.5 ±1.5. TEE was performed for 120 (27.8%) patients, more frequently for patients on NOACs and for ones with III° LA enlargement.

TEE revealed LA thrombi in seven (5.8%) of the patients. In warfarin and NOACs groups thrombi were revealed in five (7.0%) and two (4.1%) patients, respectively. TEE did not reveal any thrombi in patients with normal left ventricular (LV) function; however, thrombi were found in two (6.1%) patients with slightly decreased LV function, and in five (17.9%) patients with markedly decreased LV function.

In patients with decreased left ventricular ejection fraction (LVEF) thrombi in LA were found more frequently than in patients with normal and slightly decreased LVEF (17.9% vs 2.2%, p=0.008). CHA2DS2-VASc score of all 7 patients was ≥5. None of the patients after cardioversion had TE complications 30 days after discharge.

Conclusions

The risk of LA thrombi in patients prepared for scheduled cardioversion in line with the guidelines is low. Higher risk of thrombi was present in patients with decreased LVEF (≤40%), CHA2DS2-VASc ≥5. In order to assess more accurately indications to perform TEE for appropriately anticoagulated patients prior to scheduled cardioversion a study with larger number of patients is required.

Pharmacologic cardioversion with intravenous amiodarone is likely safe in neurocritically Ill patients

Neurological injury is often associated with cardiac abnormalities, including electrophysiological issues. Cardioversion of acute atrial fibrillation (<48h' duration) without anticoagulation carries about a 0.7% risk of thromboembolism. There is limited data on managing acute atrial fibrillation specifically in the neuroscience intensive care unit (NSICU) setting. We sought to determine the safety of using intravenous (IV) amiodarone for restoring sinus rhythm in patients with presumed new onset atrial or ventricular tachycardia after neurological injury. We conducted a retrospective review of consecutive patients admitted to our NSICU between June 2011 and March 2015 with a primary neurological diagnosis and new onset tachyarrhythmias who received IV amiodarone. Baseline demographics and presence of known risk factors for atrial fibrillation were recorded. The primary end point was new onset stroke. 48 patients were included for the final analysis. No patients developed new stroke after receiving IV amiodarone. The average follow up period was 14.0days. The majority of patients did not have the pre identified risk factors for atrial fibrillation. Ischemic stroke and traumatic brain injury were the most common admitting diagnoses. We conclude that in patients with primary neurological injury, use of IV amiodarone for rhythm control of acute onset atrial fibrillation carries a low risk of cardioembolic stroke in the first 2weeks. Further investigation, including prospective studies, with larger samples and longer follow up periods is warranted.

Close look at the experiences of patients enrolled in a clinical trial of acupuncture treatment for atrial fibrillation in Korea: a qualitative study nested within a randomised controlled trial

OBJECTIVE

To explore the experiences of patients with atrial fibrillation (AF) in the context of a prospective, two-parallel-armed, participant-blinded and assessor-blinded sham-controlled randomised trial.

DESIGN

A nested qualitative study within an ongoing randomised controlled trial to explore acupuncture's antiarrhythmic effects on drug refractory acupuncture in persistent atrial fibrillation (AF) (ACU-AF trial).

PARTICIPANTS

Participants were recruited using purposeful sampling and a maximum variation strategy with regard to treatment allocation (treatment or control) and protocol completion (completion or non-completion).

SETTING

This was a single-centre in-depth interview qualitative study conducted at a tertiary-level university hospital in Seoul, Republic of Korea.

RESULTS

Data saturation was reached after 8 participants. Thematic analysis identified that most patients were not aware of their condition until medical check-up; physician referral was the main reason for trial participation, and patients had high expectations regardless of previous acupuncture experiences. Patients tended to depend on their physicians' opinions because they felt helpless of their condition. No one questioned their assigned treatment groups and generally believed acupuncture treatment was different for cardiovascular diseases. A few patients expressed disappointment in the strict and rigid protocols, in which most practitioners refrained from explaining their acupuncture procedures.

CONCLUSIONS

For cardiovascular patients their physician's advice was one of the biggest reasons for enrolling in the acupuncture trial therefore relying on standard recruitment methods may not be effective. Fortunately both real and sham acupuncture groups in our sample were receiving treatment as intended, but in the future, designing a more pragmatic trial (better reflecting clinical settings, expanding the inclusion criteria and using more treatment points) will allow researchers to better explore the comprehensive effects of acupuncture. The findings of this study will allow researchers to improve the currently ongoing ACU-AF trial and to further help interpretation of main trial outcomes once the trial is completed.

TRIAL REGISTRATION NUMBER

NCT02110537.

Vitamin C for preventing atrial fibrillation in high risk patients: a systematic review and meta-analysis

Background

Atrial fibrillation (AF), a common arrhythmia contributing substantially to cardiac morbidity, is associated with oxidative stress and, being an antioxidant, vitamin C might influence it.

Methods

We searched the Cochrane CENTRAL Register, MEDLINE, and Scopus databases for randomised trials on vitamin C that measured AF as an outcome in high risk patients. The two authors independently assessed the trials for inclusion, assessed the risk of bias, and extracted data. We pooled selected trials using the Mantel-Haenszel method for the risk ratio (RR) and the inverse variance weighting for the effects on continuous outcomes.

Results

We identified 15 trials about preventing AF in high-risk patients, with 2050 subjects. Fourteen trials examined post-operative AF (POAF) in cardiac surgery patients and one examined the recurrence of AF in cardioversion patients. Five trials were carried out in the USA, five in Iran, three in Greece, one in Slovenia and one in Russia.

There was significant heterogeneity in the effect of vitamin C in preventing AF. In 5 trials carried out in the USA, vitamin C did not prevent POAF with RR = 1.04 (95% CI: 0.86–1.27). In nine POAF trials conducted outside of the USA, vitamin C decreased its incidence with RR = 0.56 (95% CI: 0.47–0.67). In the single cardioversion trial carried out in Greece, vitamin C decreased the risk of AF recurrence by RR = 0.13 (95% CI: 0.02–0.92).

In the non-US cardiac surgery trials, vitamin C decreased the length of hospital stay by 12.6% (95% CI 8.4–16.8%) and intensive care unit (ICU) stay by 8.0% (95% CI 3.0–13.0%). The US trials found no effect on hospital stay and ICU stay. No adverse effects from vitamin C were reported in the 15 trials.

Conclusions

Our meta-analysis indicates that vitamin C may prevent post-operative atrial fibrillation in some countries outside of the USA, and it may also shorten the duration of hospital stay and ICU stay of cardiac surgery patients. Vitamin C is an essential nutrient that is safe and inexpensive. Further research is needed to determine the optimal dosage protocol and to identify the patient groups that benefit the most.

Electronic supplementary material

The online version of this article (doi:10.1186/s12872-017-0478-5) contains supplementary material, which is available to authorized users.

Prediction of ineffective elective cardioversion of atrial fibrillation: a retrospective multi-center patient cohort study

BACKGROUND

Elective cardioversion (ECV) of atrial fibrillation (AF) is a standard procedure to restore sinus rhythm. However, predictors for ineffective ECV (failure of ECV or recurrence of AF within 30 days) are unknown.

METHODS

We investigated 1998 ECVs performed for AF lasting >48 h in 1,342 patients in a retrospective multi-center study. Follow-up data were collected from 30 days after ECV.

RESULTS

Median number of cardioversions was one per patient with a range of 1-10. Altogether 303/1998 (15.2%) ECVs failed. Long (>5 years) AF history and over 30 days duration of the index AF episode were independent predictors for ECV failure and low (<60/min) ventricular rate of AF predicted success of ECV. In patients with successful ECVs an early recurrence of AF was detected in 549 (32.4%) cases. Female gender, high (>60/min) ventricular rate, renal failure and antiarrhythmic agents at discharge were the independent predictors for recurrence. In total ECV was ineffective in 852 (42.6%) cases. Female gender (OR 1.44, CI95% 1.15-1.80, p < 0.01), young (<65 years) age (OR 1.31, CI95% 1.07-1.62, p = 0.01), ventricular rate >60/min (OR 1.92, CI95% 1.08-3.41, p = 0.03), antiarrhythmic medication at discharge (OR 1.48, CI95% 1.14-1.93, p < 0.01) and low (<60/ml/min) estimated glomerular filtration rate (OR 1.59, CI95% 1.08-2.33, p = 0.02) were predictors of ineffective ECV.

CONCLUSIONS

Female gender, use of antiarrhythmic drug therapy and renal failure predicted both recurrence of AF and the composite end point. For the first time in a large real-life study several clinical predictors for clinically ineffective ECV were identified.

Antiarrhythmic Drug Therapy for Atrial Fibrillation

Atrial fibrillation (AF) is the most frequently encountered arrhythmia. Prevalence increases with advancing age and so as its associated comorbidities, like heart failure. Choice of pharmacologic therapy depends on whether the goal of treatment is maintaining sinus rhythm or tolerating AF with adequate control of ventricular rates. Antiarrhythmic therapy and conversion of AF into sinus rhythm comes with the side effect profile, and we should select best antiarrhythmic therapy, individualized to the patient. New antiarrhythmic drugs are being tested in clinical trials. Drugs that target remodeling and inflammation are being tested for their use as prevention of AF or as upstream therapy.

Matrix Metalloproteinase Neutrophil Gelatinase-Associated Lipocalin Complex Predicts Atrial Fibrillation Recurrence after Electrical Cardioversion in Obese Patients

BACKGROUND

There is not much data on matrix metalloproteinase neutrophil gelatinase-associated lipocalin (MMP-NGAL) complex in patients with atrial fibrillation (AF).

AIM

The aim of the study was to assess the value of MMP-NGAL complex in predicting AF recurrence after electrical cardioversion.

METHODS

The serum levels of NGAL, cystatin C, interleukin-6, high-sensitivity C-reactive protein, copeptin, MMP-NGAL complex, matrix metalloproteinase 2, tissue inhibitor of metalloproteinase 1, Von Willebrand factor, B-type natriuretic peptide and the urinary level of NGAL were evaluated before cardioversion.

RESULTS

A total of 83 patients with persistent AF were enrolled in the study. Left atrial diameter (LA) ≥4.5 cm was significantly associated with AF recurrence at follow-up (p = 0.009). In selected 39 obese patients, MMP-NGAL complex was associated with AF recurrence (p = 0.03). If the concentration of MMP-NGAL complex increased by 1 ng/ml, the odds of AF recurrence increased by 4% (OR 1.04; CI: 1.00-1.08; p = 0.03). MMP-NGAL complex did not correlate with AF recurrence in patients with a first episode of AF, in patients ≥65 years of age and in patients with a LA ≥4.5 cm or with chronic kidney disease.

CONCLUSIONS

It is known that the greater the BMI at baseline, the higher the likelihood of progression from paroxysmal to permanent AF. However, European Society of Cardiology (ESC) guidelines do not consider obese patients a population with a low likelihood of success of cardioversion. That is why we need a sensitive marker to predict sinus rhythm maintenance in such a population. We found that MMP-NGAL complex may predict AF recurrence after successful cardioversion in obese patients.

Poor anticoagulation relates to extended access times for cardioversion and is associated with long-term major cardiac and cerebrovascular events

BACKGROUND

Patients undergoing elective electrical cardioversion (ECV) for atrial fibrillation have a temporarily increased risk of thromboembolism. Current guidelines recommend adequate anticoagulation for ≥3 consecutive weeks precardioversion, i.e. consecutive INR values 2.0-3.0 in patients with vitamin K antagonists (VKA). We aimed to evaluate the occurrence and impact of subtherapeutic INRs precardioversion and to study factors associated with these unwanted fluctuations.

METHODS

We recruited 346 consecutive patients undergoing elective ECV in the Maastricht University Medical Centre between 2008 and 2013. Predictors of subtherapeutic INR values were identified and incorporated into a logistic regression model.

RESULTS

A subtherapeutic INR precardioversion occurred in 55.2% of patients. The only statistically significant predictor was VKA-naivety (Odds Ratio (OR) 4.78, 95% Confidence Interval (CI) 2.67-8.58, p<0.001). In patients with ≥1 subtherapeutic INR precardioversion, time from referral until cardioversion was 91.1±42.8days, compared to 41.7±26.6days (p<0.001) in patients without subtherapeutic INRs. No thromboembolic events occurred <30days after the ECV. Independent predictors for the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion (n=30, median follow-up of 374days) were coronary artery disease in the history (OR 3.35, 95%CI 1.54-7.25, p=0.002) and subtherapeutic INR precardioversion (OR 3.64, 95%CI 1.43-9.24, p=0.007).

CONCLUSIONS

The use of VKA often results in subtherapeutic INRs precardioversion and is associated with a significant delay until cardioversion, especially in patients with recent initiation of VKA therapy. Furthermore, subtherapeutic INR levels prior to ECV are associated with the combined endpoint of cardiovascular death, ischemic stroke and the need of blood transfusion.

Evaluation of left atrial appendage function and thrombi in patients with atrial fibrillation: from transthoracic to real time 3D transesophageal echocardiography

The detection of embolic sources in patients with atrial fibrillation (AF) is important to guide anticoagulant therapy. Two-dimensional transesophageal echocardiography (TEE) is the gold standard to study left atrial appendage (LAA) anatomy and morphology, despite some false-positive diagnosis. We hypothesized that real time 3D TEE (RT3DTEE) is superior to 2DTEE in detecting and/or excluding LAA thrombi. We studied 93 patients with non-valvular AF (60 males, age = 67.1 ± 14.2 years) referred for electric cardioversion with transthoracic, 2DTEE and RT3DTEE. Before cardioversion, TTE allowed a confident measurement of emptying velocity of LAA (LAAeV) only in 59/93 patients (63%). On the contrary a good quality TEE LAAeV was obtained in all patients with 49/93 (53%) dysfunctional LAA (LAAeV < 40 cm/s). A subgroup of 5 patients (7.2% of the 69 effective cardioversion) presented a persistent dysfunction after cardioversion (with LAAeV values of <40 cm/s on the TEE post-CV). TEE allowed to observe a bilobed shape in 45 patients (48.4%) and three lobes in 22 patients (23.7%). In addition, besides to several additional findings, 2DTEE managed to detect thrombi with certainty in 8/93 patients (8.6%). In other 5 cases with diagnostic doubts for thrombi with 2DTEE (5/93 patients: 5.4%), the addition of the RT3DTEE mode allowed to discriminate with certainty the presence of just pectinate muscles in 4 patients RT3DTEE in patients with AF at risk of embolism is feasible, accurate and showed an additional diagnostic capability in the differential diagnosis of selected cases with suspected LAA thrombi.

Efficacy and Safety of Non-Vitamin K Antagonist Oral Anticoagulants After Cardioversion for Nonvalvular Atrial Fibrillation

BACKGROUND

Non-vitamin K oral anticoagulants (NOACs) are proven alternatives to vitamin K antagonists (VKAs) for the prevention of thromboembolism in patients with nonvalvular atrial fibrillation. However, there are few data on the efficacy and safety of NOAC therapy after cardioversion, where the risk of thromboembolic events is heightened.

METHODS

We performed a random-effects meta-analysis of patients who underwent both electrical and pharmacologic cardioversion for atrial fibrillation in the RE-LY, ROCKET-AF, ARISTOTLE, ENGAGE AF-TIMI 48, and X-VeRT trials. We assessed Mantel-Haenszel pooled estimates of risk ratio (RR) and 95% confidence intervals (CIs) for stroke/systemic embolism and major bleeding at ≤42 days of follow-up.

RESULTS

The analysis pooled 3949 patients in whom a total of 4900 cardioversions for atrial fibrillation were performed. Compared with VKAs, NOAC therapy was associated with a similar risk of stroke/systemic embolism (RR 0.84; 95% CI, 0.34-2.04) and major bleeding (RR 1.12; 95% CI, 0.52-2.42); no significant statistical heterogeneity was found among studies (Cochrane Q P = .59, I(2) = 0% for stroke/systemic embolism; P = .47; I(2) = 0% for major bleeding).

CONCLUSIONS

The short-term incidences of thromboembolic and major hemorrhagic events after cardioversion on NOACs were low and comparable to those observed on dose-adjusted VKA therapy. Non-vitamin K oral anticoagulants are a reasonable alternative to VKAs in patients undergoing cardioversion.

Circulating biomarkers of fibrosis and cardioversion of atrial fibrillation: A prospective, controlled cohort study

INTRODUCTION

External direct current cardioversion (DCCV) is an established treatment for AF but is associated with procedural risk and high AF recurrence rates. Cardiac fibrosis has been associated with AF, and circulating biomarkers have been suggested as a method of its assessment, but which biomarkers are suitable is yet to be determined. This study examines the differences between levels of procollagen type III N terminal peptide (PIIINP), type I collagen carboxyl telopeptide (ICTP), galectin-3 (gal-3) and fibroblast growth factor 23 (FGF-23) in DCCV patients, and disease-and-age-matched controls. Their predictive value for AF recurrence was analysed.

METHODS

79 patients undergoing DCCV and 40 age-and-disease-matched controls were included. Biomarkers were analysed using ELISA. Linear regression was used to examine relationships between biomarker levels and baseline characteristics, including echocardiographic measurements. Cox regression was used to assess relationships between baseline characteristics, including biomarker levels, and AF recurrence.

RESULTS

There was no statistically significant difference between biomarker levels in the DCCV and control groups. Diabetes mellitus was related to higher FGF-23 (p=0.007) and PIIINP (p=0.027). Female sex (p=0.014), hypertension (p=0.001), and higher body mass index (p≤0.001) were related to higher gal-3 levels. FGF-23 was weakly predictive of AF recurrence (HR 1.003 p=0.012).

CONCLUSION

PIIINP, ICTP, and Gal-3 are not predictive of AF recurrence after DCCV. FGF-23 may be associated with arrhythmia recurrence, but further work is required to clarify this. The presence of AF has no effect on levels of these biomarkers when compared to age and disease-matched controls.

Anti-arrhythmic strategies for atrial fibrillation: The role of computational modeling in discovery, development, and optimization

Atrial fibrillation (AF), the most common cardiac arrhythmia, is associated with increased risk of cerebrovascular stroke, and with several other pathologies, including heart failure. Current therapies for AF are targeted at reducing risk of stroke (anticoagulation) and tachycardia-induced cardiomyopathy (rate or rhythm control). Rate control, typically achieved by atrioventricular nodal blocking drugs, is often insufficient to alleviate symptoms. Rhythm control approaches include antiarrhythmic drugs, electrical cardioversion, and ablation strategies. Here, we offer several examples of how computational modeling can provide a quantitative framework for integrating multiscale data to: (a) gain insight into multiscale mechanisms of AF; (b) identify and test pharmacological and electrical therapy and interventions; and (c) support clinical decisions. We review how modeling approaches have evolved and contributed to the research pipeline and preclinical development and discuss future directions and challenges in the field.

Dabigatran Versus Warfarin for Direct Current Cardioversion in Atrial Fibrillation

Introduction

Direct current cardioversion (DCCV) is considered as the most effective treatment for atrial fibrillation (AF). AF is associated with an increased risk of thromboembolism, and DCCV may increase this risk. The current recommendation is, therefore, to anticoagulate for at least 3 weeks before DCCV and 4 weeks after the procedure.

Methods

A retrospective study of patients referred for elective DCCV as treatment for AF in Hampshire Hospitals NHS Foundation Trust was performed to compare the safety and efficacy of dabigatran with warfarin in this setting.

Results

During a 12-month period, 129 patients were referred for DCCV for the treatment of AF and 107 patients received DCCV. Fifty-four patients were anticoagulated with dabigatran, 42 patients with warfarin, and 11 patients with other direct oral anticoagulants (DOACs) with choice of agent determined following an informed discussion with the patient. The average number of days between the date of referral for DCCV and the date of DCCV for patients who were on dabigatran was 51 days, while for warfarin, this was 82 (P = 0.001). The proportion of cancelation and rescheduling for warfarin patients was 21.4%, while for dabigatran, this was 5.5%. Patients were reviewed 6–20 weeks after DCCV; the success rate of DCCV for dabigatran patients was 61%, whilst for warfarin patients, this was 52%. The success rate went up to 69% for patients who received DCCV within 45 days of referral (P = 0.165).

Conclusion

This retrospective study supports clinical experience that DCCV is more likely to be successful when there is a shorter duration between the onset of AF and the date of DCCV, and shows that the use of dabigatran in comparison with warfarin facilitates earlier DCCV.

Non-vitamin K antagonist oral anticoagulants versus warfarin for cardioversion of atrial fibrillation in clinical practice: A single-center experience

Background

Anticoagulation therapy with the vitamin K antagonist (VKA) warfarin has been demonstrated to reduce thromboembolic risk after electrical cardioversion (ECV). However, data concerning ECV with non-VKA oral anticoagulants (NOACs) is limited. The objective of this study was to determine the efficacy and safety of NOACs in patients undergoing ECV in a real-world clinical practice at a single center in Japan.

Methods

We retrospectively analyzed the data of 406 consecutive patients who underwent ECV for atrial fibrillation (AF) or flutter under anticoagulation with one of the three NOACs (n=149) or with a VKA (n=257).

Results

The CHADS2 and HAS-BLED scores were significantly higher in the VKA group, whereas the NOACs group had a tendency toward greater spontaneous echo contrast grades. After ECV, ischemic stroke occurred in three patients of the VKA group and one patient in the NOAC group, all of whom had persistent AF, indicating no significant difference in the thromboembolic event rate within 30 days following ECV. No other thromboembolic events, major bleeding, or death occurred in either group. Among the NOAC and VKA patients in whom we newly introduced an oral anticoagulant to perform ECV, the number of days leading to ECV was significantly lesser for the NOAC patients.

Conclusion

NOACs may be used as an alternative to VKAs for ECV and may allow prompt ECV in clinical practices.

Safety and efficacy of vernakalant for the conversion of atrial fibrillation to sinus rhythm; a phase 3b randomized controlled trial

BACKGROUND

Atrial fibrillation (AF) is a common cardiac arrhythmia that is associated with significant health risks. One strategy to mitigate the risks associated with long-term AF is to convert AF to sinus rhythm (SR). This study assessed the efficacy and safety of vernakalant hydrochloride for the pharmacological conversion of AF to SR.

METHODS

Patients with recent-onset (duration >3 h- ≤ 7 days) symptomatic AF and no evidence or history of congestive heart failure were randomized in a 2:1 ratio to receive vernakalant or placebo. Patients received an infusion of vernakalant (3 mg/kg) or placebo over 10 min, followed by a second infusion of vernakalant (2 mg/kg) or placebo 15 min later if AF had not been terminated. The primary efficacy endpoint was conversion of AF to SR for at least 1 min within 90 min of the start of drug infusion. The primary safety endpoint was a composite of: occurrence of clinically significant hypotension, clinically significant ventricular arrhythmia (including torsades de pointes, ventricular tachycardia or ventricular fibrillation) or death within 2 h of starting the drug infusion.

RESULTS

A total of 217 patients were randomized to receive vernakalant (n = 145) or placebo (n = 72). Of the 129 individuals who received vernakalant, 59 (45.7 %) converted to SR compared with one of the 68 patients (1.5 %) who received placebo (p < 0.0001). Conversion to SR was significantly faster with vernakalant than with placebo (p < 0.0001), and a greater proportion of patients who received vernakalant than those who received placebo reported no AF-related symptoms at 90 min (p = 0.0264). The primary composite safety endpoint was observed in one patient receiving vernakalant and in no patients receiving placebo. In the vernakalant arm, dysgeusia, paraesthesia and sneezing were the most common treatment-emergent adverse events, and three serious adverse events occurred that were considered to be related to study drug.

CONCLUSIONS

Vernakalant resulted in rapid cardioversion of recent-onset AF in almost half of the study population and was generally well tolerated. The safety outcomes affirmed the need for careful selection and management of haemodynamically stable candidates for cardioversion.

TRIAL REGISTRATION

NCT00989001 .

Left atrial thrombi and spontaneous echo contrast in patients with atrial fibrillation : Systematic analysis of a single-center experience

BACKGROUND

Atrial fibrillation is associated with a high risk for thromboembolic events. Thrombi in the left atrial appendage and spontaneous echo contrast (SEC) correlate positively with this embolic risk. We studied the laboratory, echocardiographic, and epidemiologic parameters that could predict left atrial thrombi and the intensity of the SEC.

PATIENTS AND METHODS

Between September 2013 and June 2015 we included 372 patients with atrial fibrillation before planned electrical cardioversion (transesophageal-guided strategy) in this study. After assessing the risk of stroke and bleeding (CHA₂DS₂-VASc and HAS-BLED scores), we measured the concentration of the D-dimer and B-type natriuretic peptide at the time of the transesophageal echocardiography as well as the left atrial volume and the ejection fraction during transthoracic echocardiography.

RESULTS

The ejection fraction and the CHA₂DS₂-VASc score were identified as independent predictors of both left atrial thrombi and SEC, whereas the left atrial volume could only predict the intensity of SEC. In contrast to the results of other studies, the biomarkers in this study failed to predict the outcome.

CONCLUSION

Only the echocardiographic and epidemiologic parameters were predictors of left atrial thrombi and SEC intensity, while the studied biomarkers had no predictive power. Using clinical data and transthoracic echocardiography, we can change the therapeutic strategy in high-risk patients.

A Comparison Between Dabigatran and Warfarin on Time to Elective Cardioversion

OBJECTIVE

To evaluate the use of dabigatran versus warfarin on time to elective direct current cardioversion (DCCV).

METHODOLOGY

This retrospective observational study was conducted at a single Veterans Affairs hospital in the Southwestern region of the U.S. Patients with atrial fibrillation or atrial flutter who were initiated on either warfarin or dabigatran prior to DCCV were reviewed. The time to cardioversion was compared between warfarin and dabigatran, as well as costs of therapy, rescheduling rates, and adverse events.

RESULTS

Out of 258 patients reviewed, a total of 68 patients were included in the study. All patients were male with an average age of 68 years (SD=8.6). A total of 38 patients (56%) received dabigatran and 30 patients (44%) received warfarin. Patients in both groups had a median CHADS2 and HASBLED score of 2. The median number of days to cardioversion was 34.5 (range=22-148) for dabigatran compared to 66.5 (range=32-183) for warfarin (p<0.01). Total costs of anticoagulation for warfarin averaged $183.50 (SD=95.02) from initiation of anticoagulation to the end of the required four week period following cardioversion, whereas dabigatran costs averaged $193.20 (SD=59.38). Three patients (10%) in the warfarin group had DCCV rescheduled compared to none in the dabigatran group. There was one bleeding event in the warfarin group and no thromboembolic events in either group.

CONCLUSION

The use of dabigatran prior to elective DCCV results in a significant decrease in number of days from initiation of anticoagulation to cardioversion as compared to warfarin, with a minor increase in total costs.

Minimal energy requirement for external cardioversion and catheter ablation for long-standing persistent atrial fibrillation

BACKGROUND

The minimal energy requirement (E_min) for electrical cardioversion (ECV) reflects the atrial substrate in patients with long-standing persistent atrial fibrillation (L-PeAF), but the relationship between E_minECV and radiofrequency catheter ablation (RFCA) has not yet been studied. We hypothesize that E_minECV before ablation (E_minECVpre) predicts clinical outcome of RFCA, and that catheter ablation reduces E_minECVpost.

METHODS

We included 172 patients with L-PeAF who underwent RFCA (79.7% males, 57.5±10.0 years) due to AF recurrence after ECV with an anti-arrhythmic drug (AAD). ECV began with 70J (patch electrode on anterior-posterior position) and was serially increased to 100, 150, 200, and 250J until sinus rhythm was achieved, at an average 5.0±5.6 months before RFCA. After RFCA, ECV was repeated (ECVpost) in 42 patients with recurrent AF that was not controlled by AAD.

RESULTS

(1) During 34.8±20.0 months of follow-up after RFCA, 103 patients (59.9%) showed clinical recurrence of AF after RFCA. E_minECVpre was significantly higher in patients with recurrent AF (129.0±58.6J) than those who remained in sinus rhythm (94.2±39.4J, p<0.001). (2) E_minECVpre ≥150J (HR=3.31, 95% CI 2.18-5.03, p<0.001) and left atrial volume index (HR=1.02, 95% CI 1.00-1.04, p=0.021) were significantly associated with post-RFCA recurrence. (3) Shorter post-RFCA recurrence timing was also independently related to E_minECVpre (β=-0.147, 95% CI -0.20 to -0.09, p<0.001). (4) Among 103 patients with recurrent AF after RFCA, 42 AAD-resistant AF patients underwent ECVpost. E_minECVpost (100.9±50.8J) was significantly lower than E_minECVpre (130.0±66.1J, p=0.006).

CONCLUSIONS

Higher E_minECVpre was independently associated with clinical recurrence and earlier recurrence timing of AF after catheter ablation among patients with AAD-resistant L-PeAF. Catheter ablation for L-PeAF significantly reduces E_minECV.

Magnitude of increase in QTc interval after initiation of dofetilide in patients with persistent atrial fibrillation is associated with increased rates of pharmacological cardioversion and long-term freedom from recurrent atrial fibrillation

BACKGROUND

Dofetilide is a class III antiarrhythmic drug approved for the treatment of atrial fibrillation (AF). Dofetilide-induced corrected QT (QTc) interval prolongation is a surrogate for the degree of drug effect, but the relationships between drug-induced QTc interval prolongation, pharmacological cardioversion (PCV), and freedom from recurrent AF are unclear.

OBJECTIVE

The purpose of this study was to assess associations between QTc interval change during dofetilide initiation and PCV and long-term AF recurrence.

METHODS

We performed retrospective analyses of a prospective cohort of patients with AF admitted for dofetilide initiation between 2001 and 2014. Clinical characteristics and electrocardiographic variables were assessed. We evaluated outcomes of successful PCV in patients with persistent AF and time to recurrence of AF in patients with paroxysmal and persistent AF.

RESULTS

During the study, 243 patients with persistent AF and 176 patients with paroxysmal AF initiated dofetilide. PCV occurred in 93/243 (41.7%) patients with persistent AF. After multivariable adjustment, QTc interval change was associated with PCV (adjusted odds ratio 1.21; P = .003 per 10-ms QTc increase). Inhospital QTc interval change was associated with long-term freedom from AF in patients with persistent AF (adjusted hazard ratio 0.92; P = .011 at 4 years per 10-ms QTc increase), but not in patients with paroxysmal AF. In patients with persistent AF, PCV was also associated with long-term freedom from recurrent AF (adjusted hazard ratio 0.62; P = .009 at 4 years).

CONCLUSION

The magnitude of QTc interval prolongation during dofetilide initiation is an independent predictor of successful PCV and long-term freedom from arrhythmia in patients with persistent AF. QTc interval change had no association with AF recurrence in patients with paroxysmal AF, suggesting that different mechanisms of arrhythmogenesis may be operant in different AF types.

Reduction over time of QTc prolongation in patients with sotalol after cardioversion of atrial fibrillation

BACKGROUND

Sotalol is recommended to prevent relapse of atrial fibrillation after cardioversion (CV). Sotalol prolongs the action potential by blocking the rapid component of the delayed rectifier potassium current, which results in corrected QT (QTc) prolongation on the electrocardiogram. Pronounced QTc prolongation may lead to proarrhythmias and sudden death.

OBJECTIVE

We investigated the dynamics of the QTc interval during the week after CV in patients treated with sotalol compared with patients treated with a β-blocker.

METHODS

Patients who underwent elective CV for persistent atrial fibrillation and maintained sinus rhythm for 1 week were included prospectively. All patients were on the highest tolerable stable dose of metoprolol or sotalol. Twelve-lead electrocardiograms were recorded 1 hour and 1 week after CV.

RESULTS

A total of 104 patients on sotalol and 104 on metoprolol were included; clinical characteristics between groups were comparable. One hour after CV, the QTc interval was significantly longer in sotalol-treated patients than in metoprolol-treated patients (465 ± 25 ms vs 423 ± 30 ms; P ≤ .0001). After 1 week, the QTc interval was reduced by -20.3 ± 24 ms in sotalol-treated patients (P ≤ .001); no such effect was seen in metoprolol-treated patients (-2.5 ± 18 ms; P = 0.28). The heart rate was stable during the week in both groups. In multivariate analysis of sotalol-treated patients, factors contributing to pronounced reduction in the QTc interval were longer QTc interval after CV and renal function.

CONCLUSION

The QTc interval is significantly reduced during the week after CV to sinus rhythm in sotalol-treated patients. This provides insight into the increased risk of proarrhythmias in the immediate time period after CV.

Heart Failure and Atrial Fibrillation

Atrial fibrillation is commonly experienced by patients with heart failure, and as the heart failure progresses and worsens, the more likely the patient is to develop atrial fibrillation. Several factors play into this, including common risk factors, such as advanced age, hypertension, and ischemic or valvular heart disease. Treatment is aimed at anticoagulation, to prevent thromboembolic stroke, and rate control to prevent further hemodynamic compromise. Rhythm control may be beneficial for many patients and this can be accomplished through the use of antiarrhythmic medications, cardioversion, and/or ablation.

[Non-vitamin K oral anticoagulants and cardioversion]

Direct oral anticoagulants are now frequently used in patients experiencing atrial fibrillation. Some of these patients may need a cardioversion. How to manage the procedure in these patients? Can we perform the procedure in patients taking the direct oral anticoagulant? Should we switch the treatment to a vitamin K antagonist? When do we need to perform a transesophageal echocardiography? All these questions justify this review article.