Shorter Atrial Fibrillation Duration Research Articles

Reduced esophageal heating in high-power short-duration atrial fibrillation ablation in the contact force catheter era.

Atrial fibrillation (AF) ablation is alternative treatment to medical therapy. Most feared complication is atrioesophageal fistula METHODS: Observational, retrospective analysis of consecutive 355 patients undergoing first AF ablation. Low-power long-duration (LPLD) group contained 158 patients, with 121 (76.58%) having paroxysmal AF who underwent ablation with power 20/30W (anterior and posterior left atrial wall), 17mL/min flow, and a contact force of 10-30g for 30s. High-power short-duration group (HPSD) contained 197 patients, with 113 (57.36%) having paroxysmal AF who underwent ablation at 45/50W of power with a contact force of 8-15g/10-20g and a 35mL/min flow rate for 6-8s on the anterior and the posterior left atrial wall, respectively. Both groups had pulmonary veins isolated and atrial flutter was ablated when needed. For patients not in sinus rhythm, cardioversion was performed before ablation RESULTS: There were no complications. LPLD group: Left atrial time 118.74min, total 145.32min, radiofrequency time 4317.99s, X-ray 13.42min, and elevation of luminal esophageal temperature (LET) in 132 (84.53%) patients. HPSD group: Left atrial time 72.16min, total 93.76min, radiofrequency time 1511.29s, X-ray 7.6min, and LET elevation in only 75 (38.07%) patients. A markedly higher rate of first-pass isolation was observed in HPSD compared to LPLD, 77.16% versus 13.29%, respectively. Recurrence occurred in 64 (40.50%) and 32 (16.24%) in 28.45 and 22.35 months in LPLD and HPSD patients, respectively. In LPLD, 10 patients were submitted to endoscopy, and one (10%) had mild erythema and in HPSD, 13 performed the endoscopy, with two (15.38%) patients showing mild erythema CONCLUSION: HPSD technique compared to the LPLD technique showed significant reduced radiofrequency and fluoroscopy times, higher rate of first-pass isolation, lower recurrence rate, and esophageal temperature elevation and may also have a protective effect avoiding incidental esophageal injury due to these findings.

Early discharge after cryoablation procedure: is it safe?

Abstract Funding Acknowledgements Type of funding sources: None. Introduction Discharge after overnight hospital stay is standard procedure in patients submitted to elective atrial fibrillation (AF) ablation. Taking into consideration the low rate of cryoablation procedure complications could the same day discharge be an option? Purpose To access the safety of same day discharge of patients submitted to AF cryoablation. Methods Single-center retrospective study of consecutive pts admitted to elective AF cryoablation in a tertiary center between February 2017 and November 2020. Patients were divided into two groups: same day discharge and next day discharge. Only patients submitted to ablation until 4 p.m. were included. Complication rates were obtained up to six months after the procedure. Complications were defined as death, pericardial tamponade, hematoma requiring evaluation and/or intervention, major bleeding requiring transfusion, hospital admission related to the procedure. Results One hundred fifty-four pts were included, with a mean age of 61 ± 10.9 years, 66.2% were males, 18.2% with diabetes, 65.6% with dyslipidemia, 77.9% with hypertension, 10.4% with chronic kidney disease KDIGO stage 3 or more. Median follow-up of 436 (IQ 178 – 729) days. Most of the pts had paroxysmal (73.4%) and persistent short duration AF (23.4%). Sixty-two pts (40.3%) were early discharged and there were no differences between the two groups regarding epidemiological and clinical characteristics (p = NS). A very low rate of complications in both groups was observed, occurring in 6.5% of pts with early discharge and in 8.7% of pts in overnight stay, without statistical significance between the two groups (p = 0.61). The most frequent complications were local hematoma (5 pts, 2 in early discharged group), pericardial effusion (3 pts, all in overnight stay), femoral pseudo-aneurism (2 pts, 1 in each group) and arteriovenous fistula (1 pt in overnight stay group). The type of complications did not differ between the two groups (p = 0.51). Two pts died during the follow up, unrelated with the procedure. In addition, no difference in success rate and arrhythmic recurrence was observed between the two groups. (p = NS) Conclusion Our study suggests that is safe to early discharge pts submitted to AF ablation, reducing the hospital stay length in selected pts. Larger studies are needed to confirm this data before routine implementation of this strategy.

Antithrombotic treatment management in low stroke risk patients undergoing cardioversion of atrial fibrillation

Data supporting the safety of cardioversion (CV) of atrial fibrillation (AF) without anticoagulation in patients with AF duration <48 h are scarce. Observational studies suggest that the risk of stroke in these patients is very low when the definite duration of the AF episode is of <48 h and the clinical risk profile as estimated through the CHA2DS2VASc score is low (a score of 0 for men and 1 for women). As the recent 2020 European Society of Cardiology (ESC) guidelines indication for this clinical scenario is based mainly on consensus, we sent out a survey to assess the current clinical practice on anticoagulation prior to and post-CV in patients with AF <24-48 h duration and low stroke risk across centres in Europe. Of the 136 respondents, half were affiliated to university hospitals (68/136; 50%). Non-university hospitals (50/136; 36%) and private hospitals (2/136; 1.4%) accounted over a third of respondents. The main findings of our survey were (i) heterogeneity in the anticoagulation management both before and post-CV in low stroke-risk patients with AF <48 h, (ii) higher utilization of periprocedural low-molecular-weight heparin than of non-vitamin K antagonist oral anticoagulant, (iii) higher utilization of pre-CV transoesophageal echocardiography for electrical CV than for pharmacological CV regardless of the duration of AF, (iv) high adherence to a 4-week post-CV oral anticoagulant (OAC) therapy, mainly for electrical CV, and finally, (v) perceived higher acceptance of lack of post-CV OAC therapy in patients with <24 h than 24-48 h episode duration. The results obtained in this survey highlight the need for more research providing definitive clarification on the safety of CV without anticoagulation in patients with short duration AF.

High-Power Short-Duration Atrial Fibrillation Ablation: Strategy to Reduce Luminal Esophageal Temperature With Contact Force Catheters

Background: Atrial fibrillation (AF) ablation is an alternative treatment to medical therapy. One of most feared complications is atrioesophageal fistula. Methods: Retrospective analysis of 355 consecutive patients undergoing first AF ablation. Low-power long-duration (LPLD) group contained 158 patients, 121 (76.58%) having paroxysmal AF underwent ablation with power 20/30W (anterior and posterior left atrial wall), 17 mL/min flow, and contact force of 10-30g/30 s. High-power short-duration group (HPSD) contained 197 patients, 113 (57.36%) paroxysmal AF underwent ablation at 45/50W power, contact force of 8-15g/10-20g and a 35 mL/min flow rate for 6-8 s on the anterior and the posterior left atrial wall, respectively. Both groups had pulmonary veins isolated and atrial flutter ablated when needed. Patients not in sinus rhythm, cardioversion was performed before ablation. Results: There were no complications. LPLD group: Left atrial time 118.74 min, total 145.32 min, radiofrequency time 4,317.99 s, X-ray 13.42 min, and elevation of luminal esophageal temperature (LET) in 132 (84.53%) patients. HPSD group: Left atrial time 72.16 min, total 93.76 min, radiofrequency time 1,511.29 s, X-ray 7.6 min, and LET elevation in only 75 (38.07%) patients. In Group A, 10 patients were submitted to endoscopy, and 1 (10%) had mild erythema. In Group B, 13 performed the endoscopy, with 2 (15.38%) patients showing mild erythema. Conclusions: The high-power short-duration technique, compared to the low-power long-duration technique, is a safe, useful, and efficient approach for reducing the LET elevation and esophageal injury because of the very significant reduction in the heating rate of this organ.

Effect of obesity and epicardial fat/fatty infiltration on electrical and structural remodeling associated with atrial fibrillation in a novel canine model of obesity and atrial fibrillation: A comparative study.

How obesity and epicardial fat influence atrial fibrillation (AF) is unknown. To investigate the effect of obesity/epicardial fat on the AF substrate, we divided 20 beagle dogs of normal weight into four groups (n = 5 each): one of the four groups (Obese-rapid atrial pacing [RAP] group) served as a novel canine model of obesity and AF. The other three groups comprised dogs fed a standard diet without RAP (Control group), dogs fed a high-fat diet without RAP (Obese group), or dogs fed a standard diet with RAP (RAP group). All underwent electrophysiology study, and hearts were excised for histopathologic and fibrosis-related gene expression analyses. Left atrial (LA) pressure was significantly higher in the Obese group than in the Control, RAP, and Obese-RAP groups (23.4 ± 6.9 vs. 11.4 ± 2.1, 11.9 ± 6.4, and 13.5 ± 2.9 mmHg; p = .005). The effective refractory period of the inferior PV was significantly shorter in the RAP and Obese-RAP groups than in the Control group (p = .043). Short-duration AF was induced at greatest frequency in the Obese-RAP and Obese groups (p < .05). Epicardial fat/Fatty infiltration was greatest in the Obese-RAP group, and greater in the Obese and RAP groups than in the Control group. %interstitial fibrosis/fibrosis-related gene expression was significantly greater in the Obese-RAP and RAP groups (p < .05). Vulnerability to AF was associated with increased LA pressure and increased epicardial fat/fatty infiltration in our Obese group, and with increased epicardial fat/fibrofatty infiltration in the RAP and Obese-RAP groups. These may explain the role of obesity/epicardial fat in the pathogenesis of AF.

Influence of obesity and epicardial fat on the progression of electrical and structural remodeling in a canine obese rapid atrial pacing model

Abstract Background Metabolic syndrome is a cluster of conditions including obesity, insulin resistance, hypertension, and abnormal cholesterol, which increases the cardiovascular risk. Metabolic syndrome or obesity has been reported to provide systemic inflammation and oxidative stress. Increased epicardial fat volume is a manifestation of obesity or metabolic syndrome. Those systemic and local conditions related to obesity or metabolic syndrome have been linking to the risk of atrial fibrillation (AF). The underlying mechanisms of obesity linking epicardial fat to AF progression have not been fully examined. Purpose To investigate the impact of obesity linked to epicardial fat on electrophysiologic and anatomical AF substrates. Methods Twenty dogs aged 3 years were divided into four groups (n=5 per each): normal diet for over 20 weeks (control group [median body weight: 12.0 kg]), rapid atrial pacing (RAP) for last 4–15 (median 8) weeks during a normal diet for the same period (RAP group [10.5 kg]), high-fat diet (HFD) maintained for over 20 weeks without RAP (MetS group [16.0 kg]), and RAP for last 4–12 (median 6) weeks during HFD maintained for 24 weeks (MetS-RAP group [17.0 kg]), respectively. Activation/voltage maps of the atria during sinus rhythm were created with Ensite NavX mapping system. The effective refractory period (ERP) at 5 left atrial (LA) and pulmonary vein (PV) sites (LA appendage [LAA], LA body, right and left superior PVs, and inferior PV), and AF inducibility by burst LAA pacing were determined. At study completion, hearts were excised for histopathological and gene expression analyses. Results The LA pressure was more significantly increased in MetS than the MetS-RAP, RAP, and control groups (22.5 [17–28.8] mmHg vs. 14.0 [10.5–16.3] mmHg, 10.5 [7.4–17.2] mmHg and 10.7 [9.6–13.5] mmHg, respectively, P&amp;lt;0.05). The LA/PV ERP at a basic cycle length of 400 ms was shorter in the MetS-RAP and RAP than MetS and control groups (118±39 ms and 122±44 ms vs. 136±18 ms and 155±39 ms, respectively, P&amp;lt;0.05). Short duration AF was more induced in the MetS and MetS-RAP than RAP and control groups (3 [0–5.5] sec and 2 [0.5–3.5] sec vs. 0 [0–4.5] sec and 0 [0–0] sec, P&amp;lt;0.05). Histological examinations showed the fatty infiltration extending from epicardial fat increased more in the Mets and Mets-RAP than RAP and control groups (Figure). The Fibronectin 1 and collagen I/III mRNA levels increased more in the MetS-RAP and AF than MetS and control groups. Conclusions AF vulnerability was associated with increased LA pressures and fibrofatty infiltration from epicardial fat in the MetS group, and with fibrofatty infiltration from epicardial fat with subtle fibrosis in the MetS-RAP group. This suggested that fibrofatty infiltration and epicardial fat plays an important role in AF pathogenesis in obese patients. Funding Acknowledgement Type of funding source: Public grant(s) – National budget only. Main funding source(s): Grant-in-Aid for Scientific Research (KAKENHI)

Antazoline for pharmacological cardioversion of atrial fibrillation: the results of the high-volume multicenter CANT study

Abstract Background Antazoline mesylate represents a first generation antihistamine with quinidine-like antiarrhythmic properties, which allows for rapid and effective termination of atrial fibrillation (AF). Despite its widespread use in Polish emergency departments, paucity of data exists concerning safety and efficacy of antazoline in comparison to other antiarrhythmic agents. Purpose This study aimed to evaluate the pooled hitherto data on effectiveness and safety of pharmacological Cardioversion with intravenous ANTazoline (CANT Study) in short-duration atrial fibrillation. Methods This retrospective observational study was performed in 5 medical centers and comprised 1300 patients with paroxysmal or persistent AF who underwent emergent pharmacological cardioversion in the real-world setting of emergency or cardiology department. The choice of antiarrhythmic drug was left to the discretion of attending physician. The exclusion criteria involved permanent AF, other supraventricular arrhythmias, including atrial flutter, chronic antiarrhythmic therapy or preemptive electrical cardioversion. The primary endpoint was restoration of sinus rhythm up to 12 hours after antiarrhythmic drug infusion. The combined safety endpoint was bradycardia &amp;lt;45 bpm, hypotension, syncope or death. Results The mean age of study population was 67.7±11.6 years and the majority of patients were men (52.9%). The median AF episode duration was 10 (4; 24) hours, while median CHA2DS2-VASc score was 3 (2; 4) pts. Antazoline alone was administered in 45.6% of patients (n=593); amiodarone in 22.1% (n=287); propafenone in 11.5% (n=150); sotalol in 0.5% (n=6), while 20.3% (n=264) received overlapping antiarrhythmic therapy. Antazoline had the highest rhythm conversion rate (Figure), which was comparable to propafenone (78.2% vs 72.7%; RR 1.08; 95% CI:0.97–1.20; P=0.175) and superior to amiodarone (vs 66.9%; RR 1.17, 95% CI:1.07–1.28; P=0.0008) and collective amiodarone/propafenone/sotalol treatment (vs 68.6%; RR 1.14; 95% CI:1.06–1.23; P=0.0006). The rate of combined safety endpoint was comparable in patients treated with antazoline and other antiarrhythmic drugs (5.2% vs 3.9%; P=0.297). Among patients treated with antazoline, 29 exhibited bradycardia &amp;lt;45 bpm and 5 patients suffered from hypotension, but no case of syncope, nor in-hospital death was reported. Conclusion Antazoline appears to be an effective antiarrhythmic drug for cardioversion of atrial fibrillation, which is associated with low rate of relatively benign adverse events. Figure 1 Funding Acknowledgement Type of funding source: None

Incidence and risk of short episodes of atrial fibrillation detected with 14 days of continuous electrocardiographic monitoring

Abstract Background There is widespread interest in population-based screening for atrial fibrillation (AF). However, there is debate regarding the optimal screening method and duration. Objectives To estimate the incidence of short-duration AF detected by a single continuous 14-day electrocardiographic (ECG) monitor in older individuals without prior AF and to estimate the risk of ischemic stroke or systemic embolism associated with these episodes. Methods Pacemaker and defibrillator electrograms were reviewed from a cohort of individuals ≥65 years old, with a history of hypertension, but no prior AF. For each participant, we simulated a continuous 14-day ECG monitor by randomly selecting a 14-day window in the 6 months following enrolment and measured the total AF burden during that period. We repeated random sampling 1000 times to ensure a robust estimate of the likelihood of capturing AF in a single 14-day period. We used Cox proportional hazards models adjusted for CHA2DS2-VASc score to estimate the risk of ischemic stroke or systemic embolism associated with different burdens of AF. Results Among 2470 participants with at least 6 months of follow-up, the mean CHA2DS2-VASc score was 4.0±1.3. The proportion of participants with an AF burden of &amp;gt;6 min on a single 14-day monitor was estimated as 3.1%, while the proportion with burdens of &amp;gt;15 min and &amp;gt;30 min were 2.9% and 2.6%, respectively. Over a mean follow-up of 2.5 years, 44 participants had an ischemic stroke or systemic embolism; the rate among patients with an AF burden ≤6 mins was 0.70%/year. An AF burden &amp;gt;6 min was associated with an increased risk of stroke or systemic embolism (2.2%/year, HR 3.0; 95% CI 1.3–5.7), as were burdens &amp;gt;15 min (2.4%/year; HR 3.3; 95% CI 1.4–6.4) and &amp;gt;30 min (2.6%/year HR 3.5; 95% CI 1.5–6.7). Conclusion Approximately 3% of individuals aged 65 years and older and with hypertension may have previously undiagnosed asymptomatic AF detected by a single 14-day continuous ECG monitor. As little as 6 minutes of AF may be associated with an increased risk of stroke. Randomized clinical trials are required to definitively assess screening in this population. Funding Acknowledgement Type of funding source: None

Effect of selective IK,ACh inhibition by XAF‐1407 in an equine model of tachypacing‐induced persistent atrial fibrillation

Inhibition of the G-protein gated ACh-activated inward rectifier potassium current, IK,ACh may be an effective atrial selective treatment strategy for atrial fibrillation (AF). Therefore, the anti-arrhythmic and electrophysiological properties of a novel putatively potent and highly specific IK,ACh inhibitor, XAF-1407 (3-methyl-1-[5-phenyl-4-[4-(2-pyrrolidin-1-ylethoxymethyl)-1-piperidyl]thieno[2,3-d]pyrimidin-6-yl]azetidin-3-ol), were characterised for the first time in vitro and investigated in horses with persistent AF. The pharmacological ion channel profile of XAF-1407 was investigated using cell lines expressing relevant ion channels. In addition, eleven horses were implanted with implantable cardioverter defibrillators enabling atrial tachypacing into self-sustained AF. The electrophysiological effects of XAF-1407 were investigated after serial cardioversions over a period of 1 month. Cardioversion success, drug-induced changes of atrial tissue refractoriness, and ventricular electrophysiology were assessed at baseline (day 0) and days 3, 5, 11, 17, and 29 after AF induction. XAF-1407 potently and selectively inhibited Kir 3.1/3.4 and Kir 3.4/3.4, underlying the IK,ACh current. XAF-1407 treatment in horses prolonged atrial effective refractory period as well as decreased atrial fibrillatory rate significantly (~20%) and successfully cardioverted AF, although with a decreasing efficacy over time. XAF-1407 shortened atrioventricular-nodal refractoriness, without effect on QRS duration. QTc prolongation (4%) within 15 min of drug infusion was observed, however, without any evidence of ventricular arrhythmia. XAF-1407 efficiently cardioverted sustained tachypacing-induced AF of short duration in horses without notable side effects. This supports IK,ACh inhibition as a potentially safe treatment of paroxysmal AF in horses, suggesting potential clinical value for other species including humans.

P427Influence of ranolazine on cardioversion rate in patients with new onset atrial fibrillation and ischemic disease of the heart

Abstract Background Ranolazine is a piperazine derivative, mainly used as antianginal drug in patients with ischemic disease of the heart (IDH). Despite its antianginal effect, it has an antiarrhythmic effect by inhibiting of late sodium and rapid potassium rectifier current. Aim of the study was to assess the additional antiarrhythmic efficacy of ranolazine in patients with new onset atrial fibrillation (AF) and IDH. Material and Methods 168 eligible patients with IDH and short duration of new onset AF were enrolled in this study. Among them, 92 were treated additionally ranolazine to the standart therapy – Group I while 76 only with standart therapy – Group II. The choice of antiarrhythmic drug for cardioversion was either amiodarone or propafenone at the discretion of the doctor. Primary endpoint was recovering of sinus rhythm. All statistical analysis were performed using student t-test. Results Mean age of patients was 66 ± 11.5 years, male 48% in ranolazine group (Group I) and 64.5 ± 12.0 years, male 46% in Group II, and there were no statistically significant differences between two groups. Both groups of patients were characterized by median AF episode duration of 12 (4; 24) hours. Amiadoron was administered in 70 % (n = 65) of patients in Group I and in 77% (n = 59); propafenon in 30% (n = 17) of patients in Group I and 23% (n = 17) in Group II. Cardioversion rate was significantly higher in Group I than Group II (87% vs. 74%, P &amp;lt; 0.05;). There were not observed safety endpoints in Group I whereas 3 safety endpoints (severe bradycardia and arterial hypotension) were observed in Group II (P &amp;gt; 0.05). Conclusion Adding ranolazine to the standard therapy in patients with IDH seems to have a beneficial role in restoring sinus rhythm in recent new onset AF.

High-power, short-duration atrial fibrillation ablations using contact force sensing catheters: Outcomes and predictors of success including posterior wall isolation

Little is known about the long-term outcomes and predictors of success of high-power, short-duration (HPSD) contact force (CF) atrial fibrillation (AF) ablations. The purpose of this study was to determine long-term freedom from AF and predictors of freedom from AF for 50-W, 5- to 15-second CF ablation. We examined 4-year outcomes and predictors of freedom from AF after AF ablation for 1250 consecutive patients undergoing HPSD CF ablations. Patient demographics were age 66.6 ± 10.5 years, female 30.9%, left atrial (LA) size 4.26 ± 0.66 cm, paroxysmal AF 35.7%, persistent AF 56.6%, and longstanding AF 7.7%. Initial ablation times were procedure 114.2 ± 45.9 minutes, fluoroscopy 15.5 ± 11.5 minutes, and total radiofrequency 20.6 ± 7.7 minutes. TactiCath was used in 47.7%, SmartTouch in 52.3%, and posterior wall isolation (PWI) was performed in 34%. Four-year freedom from AF after multiple ablations were paroxysmal AF 87.0%, persistent AF 71.9%, and longstanding AF 64.9%. Single procedure success was 74.9% for TactiCath, 64.7% for SmartTouch (P <.001), and 73.0% for no PWI vs 58.9% for PWI (P <.0001). PWI did not change outcomes for paroxysmal AF but had worse outcomes for nonparoxysmal AF. Multivariate analysis showed 6 independent predictors of worse outcome after initial ablation: older age (P = .014), female gender (P <.0001), persistent AF (P = .0001), larger LA size (P <.001), PWI (P = .049), and use of SmartTouch vs TactiCath catheter (P= .007). Redo ablations were performed in 13.8%, and the outcome was better when more veins had reconnected after the initial ablation and when AF was paroxysmal. Analysis revealed 6 independent predictors of outcome for HPSD CF. At redo ablations, the outcome was better if more veins had reconnected and could be re-isolated.

Are Patients with Short-Duration Atrial Fibrillation at Risk for Stroke?

Despite questions about the accuracy of CHA2DS2-VASc, it is useful for predicting which patients with clinically diagnosed atrial fibrillation (AF)

Atrial fibrillation occurring during head-up tilt testing: Once detected, atrial fibrillation should be monitored, regardless of how it is detected

Atrial fibrillation (AF) often progresses to more sustained forms and increases the risk of ischemic stroke or sinus node dysfunction. However, there have been no data on the clinical outcomes of patients who developed AF during head-up tilt testing (HUT). The purpose of this study was to evaluate the clinical significance of AF detected during HUT performed for syncope evaluation. We analyzed incidence, short- and long-term prognosis, and predictors of adverse outcomes of AF detected during HUT, which was performed in 6780 consecutive patients without AF history. Of the 6780 patients, 52 (0.8%) developed AF during passive tilting (n = 5), isoproterenol infusion (n = 32), and recovery phase (n = 15) of HUT, respectively. There was no short-term adverse event: spontaneous sinus conversion occurred in 43 patients (83%) within 48 hours. Over a median follow-up of 34.8months, 24 patients (46%) had AF recurrence with initial presentation as ischemic stroke (n = 2), sinus node dysfunction requiring pacemaker (n = 10), and AF alone (n = 12). In addition, 19 of 24 recurred AF cases (79.2%) progressed to persistent/permanent forms. The index AF duration was identified as an independent predictor of AF recurrence. Patients with longer AF duration (≥1.0 hour) showed worse prognosis than did those with shorter AF duration (<1.0 hour). The incidence of AF during HUT was ∼0.8%, and short-term prognosis was favorable. However, about half of the cases were complicated by long-term adverse outcomes. Therefore, regular follow-up might be warranted for patients with HUT-induced AF, particularly when AF duration is long.

Clinical effectiveness and safety of antazoline-based therapy in patients with stable coronary artery disease undergoing pharmacological cardioversion of short-duration atrial fibrillation in the emergency department.

Options for a pharmacological cardioversion (CV) of short-duration atrial fibrillation (AF) in patients with a stable coronary artery disease (CAD) are limited to amiodarone or vernakalant. Antazoline has been reported to achieve high rates of AF conversion to sinus rhythm, but data on its effectiveness and, more importantly, safety in stable CAD patients, have been sparse. To assess the effectiveness and safety of antazoline-based therapy in patients with a stable CAD undergoing pharmacological CV of short-duration AF in the emergency department (ED). A retrospective case-control study. We conducted an analysis of medical records of patients with a stable CAD undergoing CV of short duration (≤48hours) AF in the ED using intravenous antazoline. The main endpoints of the study were successful cardioversion of AF and hospitalization due to the adverse effects (AE) of the treatment. Between 2008 and 2012, out of 548 CVs, antazoline was administered 334 times: 138 in CAD and 196 in the control group. Patients in the CAD group were older and had more comorbidities than controls; 65 patients had had a history of myocardial infarction (MI). In CAD group, the effectiveness was higher (82.6% vs 63.8%, RB: 1.30 [95% CI: 1.14-1.48], P=0.0002) and the hospitalization rate due to AE was similar (1.4% vs 4.1%, RR: 0.36 [95% CI: 0.08-1.65], P=0.2054) to the control group. Among patients with CAD, a history of MI did not influence the effectiveness or safety of the CV (P=0.2252 and P=1.0000, respectively). In selected patients with a stable CAD, even with a history of MI, antazoline-based CV of short-duration AF may be an effective and safe therapeutic option.

Radiofrequency ablation in atrial fibrillation. Predicting factors for restoration of sinus rhythm

BackgroundAtrial fibrillation (AF) is the most common sustained arrhythmia. It increases the risk of thromboembolic stroke, anticoagulation induced bleeding, and the overall mortality. Restoration of the sinus rhythm may improve the quality of life and reduce the mortality. The classic ‘cut and sew’ cox maze procedure is the gold standard; however, it is complex. Bipolar radiofrequency ablation is faster and simpler. MethodsThis study included 129 patients. They underwent bipolar radiofrequency ablation for their AF in concomitant with their cardiac surgery from 2008 throughout 2016 in Morriston hospital in UK. Patients were followed up for 6 months and divided according to their rhythm at 6 months into sinus group and AF group. Peri-operative data were collected. Comparison between the two groups was done to determine the predicting factors for the restoration of the sinus rhythm. Results42 patients were in AF in 6 months, while 87 patients restored their sinus rhythm. The two groups were compared according to different parameters. The results were tabulated and analysed using different tests. The significant predicting factors were left atrial diameter (P=0.004), type of AF (P=0.005), duration of AF (P<0.001), and the rhythm at discharge (P=0.020). ConclusionsThe predicting factors for the restoration of the sinus rhythm after AF ablation were: smaller left atrial diameter, paroxysmal atrial fibrillation, short duration of atrial fibrillation, and sinus rhythm at discharge.

Matrine reduces susceptibility to postinfarct atrial fibrillation in rats due to antifibrotic properties.

This study aimed to investigate whether matrine could prevent atrial fibrillation (AF) after myocardial infarction by reducing left atrial fibrosis, and to determine the underlying mechanisms in isolated cardiac fibroblasts (CFs). Five weeks after MI, matrine-treated rats had lower rates of AF inducibility and shorter AF duration than MI rats. Matrine improved the left atrial conduction velocity and homogeneity. Matrine decreased the fibrosis positive areas and the protein levels of type I collagen and type III collagen in the left atrium. Matrine inhibited CFs differentiation to myofibroblasts and the expression of transforming growth factor-beta 1 and matrix metalloproteinase 9. In vitro, matrine inhibited the CFs proliferation, migration, differentiation, and secretion ability. These in vitro and in vivo data demonstrated that matrine has the potential to reduce susceptibility to AF after MI due, at least in part, to reduced atrial fibrosis via inhibiting CFs proliferation, migration, differentiation, and secretion ability.

Midterm outcomes of two-staged hybrid ablation of persistent and long-standing persistent atrial fibrillation using the versapolar epicardial surgical device and subsequent catheter ablation.

Hybrid ablation of atrial fibrillation (AF) is a promising treatment strategy for patients with non-paroxysmal AF, although, data regarding mid-term outcomes are limited. Patients with persistent or long-standing persistent AF were enrolled. Initially, a thoracoscopic, right-sided, epicardial ablation was performed, with a goal of creating a box lesion on the posterior wall of the left atrium; a novel versapolar radiofrequency (RF) catheter was used. In patients enrolled later, occlusion of the left atrial appendage was also performed. An endocardial procedure was performed 2-4months later, with the goal of confirming/completing the box lesion and ablating the ganglionated plexi and cavotricuspid isthmus. Efficacy was assessed using multiple 24-h and 1-week Holter monitoring. Analysis was performed to search for variables associated with procedure's failure. Forty-one patients (14 persistent and 27 long-standing persistent AF) were enrolled with a mean AF duration of 33.5±33.1months. Mean follow-up was 507.2±201.1days (180-731). At the last follow-up visit, 27(65%) patients were arrhythmia-free, without anti-arrhythmics or need for re-ablation. Additional 4 patients (9.8%) were in sinus rhythm (SR) following re-ablation of postprocedural peri-mitral flutter and 4 (9.8%) were in SR on anti-arrhythmics. Longer periods of preoperative AF were independently associated with worse arrhythmia-free survival (p=0.015). Serious postoperative complications occurred in 3 (7.3%) patients; only 1 (2.4%) patient had clinical consequences after 6months. Hybrid ablation of non-paroxysmal AF using a novel, versapolar RF device yields promising mid-term results. Better arrhythmia-free survival rates were found in AF patients with shorter AF duration.

Non-vitamin K antagonist oral anticoagulants in atrial fibrillation patients undergoing elective cardioversion.

Non-vitamin K antagonist oral anticoagulants (NOAC) have been shown to be safe and effective alternatives to warfarin for the prevention of thromboembolic complications in patients with non-valvular atrial fibrillation (AF). The aim of this study was to investigate the complications and the use of NOACs in AF patients undergoing elective cardioversion. This nationwide multicentre study included consecutive elective cardioversions in AF patients treated with NOACs between October 2011 and May 2016. Data on patient characteristics, antithrombotic treatment and acute (<30 days) complications were collected. One thousand twenty-one patients (mean age 64 years, 70% men) underwent 1291 elective cardioversions, of which 680 (52.7%) cardioversions were performed in patients using dabigatran, 431 (33.4%) rivaroxaban, and 159 (12.3%) apixaban. Mean CHA2DS2-VASc score was 1.8 (±1.5). A total of 3 thromboembolic events occurred after the cardioversion (0.2%): 1 patient receiving dabigatran experienced an ischaemic stroke on Day 2 and 1 rivaroxaban treated patient on Day 4. One patient receiving dabigatran experienced a transient ischaemic attack on Day 11. All 3 patients had used recommended doses of the NOAC. A total of 6 (0.5%) clinically relevant, but not serious bleeding events occurred. Only short duration of AF was associated with lower rate of AF recurrence. Thrombotic and bleeding complications related to NOACs were uncommon (<0.5%) in real life AF patients undergoing elective cardioversion.

Left-Sided Surgical Ablation for Patients With Atrial Fibrillation Who Are Undergoing Concomitant Cardiac Surgical Procedures

Growing evidence indicates the effectiveness of surgical ablation confined to the left atrium, especially with short duration of atrial fibrillation (AF) and smaller left atrial (LA) size. This study examined rhythm status and predictors of failure in this group of patients. Of 800 patients who underwent concomitant surgical ablation (2005 to 2015), 110 had LA-only ablation. Rhythm status was defined according to Heart Rhythm Society guidelines: sinus rhythm (SR) without class I/III antiarrhythmic drugs (AADs). Multivariate analyses examined predictors for SR without AADs. Predictors of failure were also stratified as age 75 years or older, LA size 5 cm or larger, AF duration 5 years or more, and nonparoxysmal AF type for secondary analyses. Mean age was 70.7 ± 9.4 years, mean EuroSCORE II (European System for Cardiac Operative Risk Evaluation) was 4.7 ± 4.3%, mean LA size was 4.4 ± 0.8 cm, median (interquartile range) AF duration was 3.5 months (range, 0.4 to 21 months), 26% of patients were female, 59% had coronary artery bypass graft procedures, 36% had aortic valve procedures, and 25% had mitral valve procedures. SR without AADs at 6, 12, and 24 months was 82% (79 of 96), 87% (78 of 90), and 79% (61 of 77), respectively. The only independent predictor of SR without AADs at 6 months was smaller LA size (odds ratio, 0.35; p= 0.014). Return to SR without AADs at 6, 12, and 24 months was as follows: 92%, 93%, and 91%, respectively, for patients with no traditional predictors of failure (n= 32); 88%, 90%, and 77%, respectively, for one predictor (n= 47); and 66%, 76%, and 70% for two or more predictors (n= 31). LA-only ablation yielded acceptable success rates, primarily in patients with shorter AF duration and smaller LA. However, success was reduced in patients with traditional predictors of failure. Well-designed studies with standardized lesion sets and ablation tools are required to determine whether full Cox maze yields better outcomes in patients with more advanced AF.

P059: “Rate and See” – a pilot evaluation of a short duration atrial fibrillation pathway linking the emergency department to specialty care

Introduction: Rapid atrial fibrillation (AF) and flutter remains a common cause of emergency department (ED) visits. Canadian guidelines recommend a rhythm control strategy for patients presenting to ED within 48 hours of arrhythmia onset or who are anticoagulated. However, up to 70% of patients spontaneously convert within 24 hours, mitigating the need for urgent cardioversion. Moreover, education, risk stratification, appropriate anticoagulation, and follow-up may be challenging in the ED setting. Therefore, direct and rapid linkage to an AF clinic was proposed to address these gaps in care. Methods: A pilot evaluation of a “Short Duration AF Pathway” was performed at Kelowna General Hospital, B.C., from June 2014 to Feb 2015. This care pathway–consisting of a treatment algorithm, ED order set, and referral process–was applied to patients with AF≤48 hours or those who were anticoagulated. Patients received initial rate control medication in the ED and were referred for reassessment in a collaborative cardiologist/nurse practitioner AF clinic and seen within 24 hours. Data was collected prospectively; descriptive statistics are presented. Results: Twenty patients were enrolled during the pilot period. Mean age was 69 (SD=10) years, 6/20 (30%) female, mean CHADS65 score 1.35 (SD=1.1), with 15/20 (75%) CHADS65 ≥ 1. On presentation, 4/20 (20%) were taking anticoagulants and 12/20 (60%) had an AF history. All 20 patients were assessed in the AF clinic within 24 hours of referral. Upon assessment in the AF clinic, 10/20 (50%) had spontaneously converted to sinus rhythm and 5/20 (25%) were electrically cardioverted at the first AF clinic visit. The remaining 5/20 (25%) of patients were reclassified as AF of uncertain duration; one was admitted to hospital, the other four had delayed electrical cardioversion. All patients received education related to AF. No adverse events or readmissions to the ED were reported and 100% of patients with CHADS 65≥1 had received appropriate anticoagulation. Conclusion: A “Short Duration AF Pathway” is a viable alternate approach to immediate cardioversion within the ED. Potential advantages include avoiding unnecessary cardioversion, providing patient education, accessing timely specialty care, and initiating anticoagulation where appropriate.