Successful Atrial Flutter Ablation Research Articles

Sinus Node Dysfunction after Successful Atrial Flutter Ablation during Follow-Up: Clinical Characteristics and Predictors

Identification of sinus node dysfunction (SND) before termination of persistent AFL by catheter ablation (CA) is challenging. This study aimed to investigate the characteristics and predictors of acute and delayed SND after AFL ablation. We retrospectively enrolled 221 patients undergoing CA of persistent AFL in a tertiary referral center. Patients with SND who required a temporary pacemaker (TPM) after termination of AFL or a permanent pacemaker (PPM) during follow-up were identified. Acute SND requiring a TPM was found in 14 of 221 (6.3%) patients following successful termination of AFL. A total of 10 of the 14 patients (71.4%) recovered from acute SND. An additional 11 (5%) patients presenting with delayed SND required a PPM during follow-up, including 4 patients recovering from acute SND. Of these, 9 of these 11 patients (81.8%) underwent PPM implantation within 1 year after the ablation. In multivariable analysis, female gender and a history of hypothyroidism were associated with the requirement for a TPM following termination of persistent AFL, while older age and a history of hypothyroidism predicted PPM implantation. This study concluded that the majority of patients with acute SND still require a PPM implantation despite the initial improvement. Therefore, it is reasonable to monitor the patients closely for at least one year after AFL ablation.

Atrial Fibrillation in a Patient with Interatrial Block after Successful Atrial Flutter Ablation: May Interatrial Block Be a Link for a Continuum of Atrial Arrhythmias?

Background: Electrocardiographic interatrial block (IAB) typically exists when a conduction delay over the Bachmann’s bundle is present. By analogy to other types of block, there is a continuum of IAB severity; partial IAB is defined as a P-wave duration 120 ms and advanced interatrial block (aIAB) is defined as a P-wave duration 120 ms in conjunction with biphasic P-wave morphology in inferior leads II, III, and aVF. Moreover, IAB seems to be a key factor in the genesis of atrial fibrillation (AF). On the contrary, it is not clear if the presence of advanced IAB may be associated with an occurrence of AF after cavotricuspid atrial flutter ablation in patients without previous episodes of atrial fibrillation. So, may be useful to evaluate on surface electrocardiogram the P-wave morphology and duration in sinus rhythm after the ablation procedure just to identify patients at high risk for atrial fibrillation development. Advanced IAB is frequently associated with atrial tachyarrhythmias, and it was found to predict AF and may be helpful for clinical decisions. Case presentation: In this case involving a man who underwent a typical atrial flutter ablation, we documented that aIAB during the post-ablation period which seems to induce atial fibrillation episodes. To our knowledge, it is unusual to detect an aIAB after cavotricuspid atrial flutter ablation and subsequently associate it with a new onset of AF. Conclusions: Our observation supports a possible aIAB induction of AF after cavotricuspid atrial flutter ablation and potentially may representing a link in the continuum of atrial arrhythmias. P-wave morphology and duration should be better evaluated soon after AFlu ablation to better stratify patients who are at high risk for atrial fibrillation development and eventually prolonged anti-coagulation therapy.

Oral Anticoagulation Discontinuation Following Catheter Ablation of Typical Atrial Flutter

Catheter ablation (CA) of typical atrial flutter (AFL) is the preferred treatment for typical AFL due to its excellent long-term success rate. However, current guidelines recommend pursuing oral anticoagulation (OAC) based on established indices of stroke regardless of the perceived success of ablation. We conducted a retrospective study of all patients who underwent typical AFL ablation at our institute from 2011 to 2017. All patients continued OAC for at least six weeks post-CA and underwent 24-hour Holter monitoring. OAC was discontinued if there was no evidence of recurrence at six weeks. In patients with low left ventricular ejection fraction or prior atrial fibrillation episodes, OAC was continued for six months with repeat Holter monitoring at six months. A total of 106 patients were included in our analysis, with a mean age of 64 ± 14 years and 78.3% of whom were male. The mean CHA2DS2-VASc score was 3 ± 1 points. OAC was discontinued by six weeks in 17% and at one year in 55.7% of patients, respectively, but was continued indefinitely in 44.3%. Over a mean follow-up period of 28.6 ± 27.3 months, there was one ischemic stroke in the OAC discontinuation group and no ischemic events in the continued OAC group. There were a total of three major bleeding events, all in the OAC group. In patients undergoing successful AFL ablation, a strategy of OAC discontinuation with close rhythm monitoring appears feasible. The benefit of continued OAC in this cohort may be outweighed by an adverse risk of bleeding. Further studies examining rhythm-guided OAC can minimize unnecessary exposure to long-term anticoagulation.

Refining HATCH Score with Atrial Myopathy for Predicting New-Onset Atrial Fibrillation after Atrial Flutter Ablation

Objectives: To determine markers of atrial myopathy to HATCH score ( hypertension, age > 75 years, transient ischemic attack/stroke, chronic obstructive pulmonary disease, and heart failure) can improve prediction of new-onset atrial fibrillation (AF) after ablation of typical atrial flutter (AFL).Background: It is unclear if oral anticoagulation therapy needs to be stopped or continued after successful ablation of AFL due to concern regarding incidence of new-onset AF. These practices potentially expose the substantial proportion of patients who do not develop AF to medication costs and bleeding risk. The available risk prediction models are inadequate to identify a truly low risk patient. Methods: The study included 208 consecutive patients who underwent successful ablation of typical AFL from 2006 to 2014 at Minneapolis VA Medical Center and University hospital. Patients with history of AF prior to ablation were excluded. Results: Among the 208 patients, 76 (36.5%) developed new-onset AF post AFL ablation. Mean follow up duration was 62{±}31.8 months. HATCH score was not associated with new-onset AF. When adding atrial myopathy (presence of at least one of the following: PTFV1 >5000 µV*ms, interatrial block determined by biphasic inferior p wave with duration >120ms, left atrium (LA) diameter >44 mm, or LA index >3 mm/m2 ) to HATCH score (HATCH-A), the combination was independently associated with new-onset AF. The AF incidence between HATCH-A score of 0-1 and > 2 were 6.7% and 40.5%, respectively (odds ratio 9.04, p=0.004). Conclusions: Adding atrial myopathy to HATCH score improved predictability of new-onset AF after typical AFL ablation.

P649 Before and after: sinus venosus atrial septal defect

Abstract Introduction The diagnosis of sinus venosus atrial septal defect (SVASD) is complex and requires special imaging. Surgery is the conventional treatment; however, transcatheter repair may become an attractive option. Case report A 60 year-old woman was admitted to the cardiology department with several episodes of paroxysmal atrial flutter, atrial fibrillation and atrioventricular nodal reentrant tachycardia. She reported a 10-year history of occasional palpitations which had not been studied. A transthoracic echocardiography revealed severe right ventricle dilatation and moderate dysfunction. Right volume overload appeared to be secondary to a superior SVASD with partial anomalous pulmonary venous drainage. A transesophageal echocardiography confirmed the diagnosis revealing a large SVASD of 16x12 mm (Figure A) with left-right shunt (Qp/Qs 2,2) and two right pulmonary veins draining into the right superior vena cava. Additionally, it demonstrated coronary sinus dilatation secondary to persistent left superior vena cava. CMR and cardiac CT showed right superior and middle pulmonary veins draining into the right superior vena cava 18 mm above the septal defect (Figures B and C). After discussion in clinical session, a percutaneous approach was planned to correct the septal defect and anomalous pulmonary drainage. For this purpose, anatomical data obtained from CMR and CT was needed to plan the procedure. During the intervention two stents graft were deployed in the right superior vena cava. The distal stent was flared at the septal defect level so as to occlude it while redirecting the anomalous pulmonary venous flow to the left atrium (Figure D). Control CT confirmed the complete occlusion of the SVASD without residual communication from pulmonary veins to the right superior vena cava or the right atrium (Figure E). Anomalous right superior and middle pulmonary veins drained into the left atrium below the stents. Transthoracic echocardiographies showed progressive reduction of right atrium and ventricle dilatation. The patient also underwent successful ablation of atrial flutter and intranodal tachycardia. She is currently asymptomatic, without dyspnea or arrhythmic recurrences. Conclusions In this case, multimodality imaging played a key role in every stage of the clinical process. First, it provided the diagnosis and enabled an accurate understanding of the patient’s anatomy, particularly of the anomalous pulmonary venous connections. Secondly, it allowed a transcatheter approach by supplying essential information to guide the procedure. Finally, it assessed the effectiveness of the intervention and the improvement in cardiac hemodynamics during follow-up. Abstract P649 Figure.

CHADS2 and CHA2DS2-VASc scores as tools for long-term mortality prognosis in patients with typical atrial flutter after catheter ablation.

The CHADS2and CHA2DS2-VASc scores were shown to predict mortality in patients with atrial fibrillation. However, pathophysiology and treatment outcomes of atrial fibrillation and typical atrial flutter (AFL) differ. Consequently, the prognosis of patients with AFL can also be different. The aim of the study was to assess CHADS2and CHA2DS2‑VASc scores as mortality predictors in patients with typical AFL. Large cohort of consecutive patients with typical AFL who underwent catheter ablation was retrospectively analyzed. The CHADS2and CHA2DS2‑VASc were calculated using hospital record data. All-cause mortality data was obtained from the registry of national personal identification numbers. The Kaplan-Meier method and multivariable Cox proportional hazard models were applied for survival and hazard ratio analyses, respectively. A total of 469 patients hospitalized for typical AFL ablation were enrolled (mean [SD] age, 63.7 [12.2] years; male sex, 69.1%). Patients were followed from 2 to 12 years resulting in 2974 patient‑years of follow‑up. The Kaplan-Meier survival analysis revealed a negative impact of each component of the CHADS2and CHA2DS2‑VASc scores on survival with the exception of stroke (not significant) and female sex (related to abetter survival). Consequently, higher scores were predictive of higher all‑cause mortality rates (2.7%-54% at 10 years); the CHA2DS2‑VASc score was equally predictive as the CHADS2score. In patients referred for typical AFL ablation, the CHADS2score can be applied for prognostic assessment. A successful AFL ablation procedure should not divert the attention from recognizing and addressing other medical issues that have an impact on long‑term mortality, which remains very high in this population of patients.

Successful case of complex atrial flutter occurring in a patient with congenitally corrected transposition of the great arteries, aberrant left atrial appendage, and situs inversus

BackgroundCongenitally corrected transposition of great arteries (ccTGA) is a rare congenital cardiac defect with atrioventricular and ventriculoarterial discordance which leads to heart failure and limits patients’ lifespan. The extremely aberrant cardiac structure makes electrophysiological procedure and radiofrequency ablation very difficult to be performed in such patients. Until now, there were only sporadical cases that have reported the successful ablation of atrial flutter in ccTGA patients.Case presentationWe report a case of a 36-year-old male who was diagnosed with dextrocardia, atrial septal defect and congenitally corrected transposition of great arteries (ccTGA) at a young age and received atrial septal defect repair and morphological tricuspid valve plasty in 2014. As for reasons of heart failure and atrial flutter, he frequently suffered from progressively worsening dyspnea and recurrent episodes of palpitations. Cardiac anatomic imaging reconstruction before electrophysiological test revealed an unusually huge left atrial appendage in this patient. After high-density mapping of both right atrium and left atrium, activation mapping showed reentry circuit loops were located in left atrium. Successful ablation strategy was performed under the guidance of high-density mapping and entrainment.ConclusionThis is a clinical case showing high-density mapping and successful ablation of a complex dual-loop atrial flutter in a patient with ccTGA and aberrant left atrial appendage. The successful procedure corroborates clinical utility of high-density mapping approach in the treatment of the patients with complex congenital heart disease accompanied by rapid arrhythmia, can be simpler, safer and more effective.

Elevated Incidence of Atrial Fibrillation and Stroke in Patients With Atrial Flutter—A Population-Based Study

BackgroundThe risk of stroke from atrial flutter and its relationship with progression to atrial fibrillation (AF) is unclear. This study describes the incidence of AF and stroke in patients with atrial flutter, and whether atrial flutter ablation attenuates the incidence of AF and stroke. MethodsWe performed a population-based retrospective cohort study of adults with typical atrial flutter with no AF history. Using linked health administrative databases we defined 3 cohorts: (1) adult patients diagnosed with new isolated atrial flutter; (2) a contemporary, 1-to-1 matched cohort from the Ontario population; and (3) patients with isolated atrial flutter who underwent atrial flutter ablation. ResultsA total of 9339 new typical atrial flutter patients were identified and 7248 were matched to general population subjects. Over the 3-year follow-up, AF occurred in 40.4% of patients with atrial flutter, and 3.3% of the matched general population (rate ratio, 12.2; P < 0.001). Stroke occurred in 4.1% of patients with atrial flutter and 1.2% of the general population cohort (rate ratio, 3.4; P < 0.001). Among 218 patients who had an atrial flutter ablation, AF occurred in 47 (21.6%) over the following 3 years, and incidence of stroke was between 0 and 2.3%. ConclusionsPatients with isolated atrial flutter develop AF and stroke at a higher rate than the general population. Catheter ablation reduces but does not eliminate future AF incidence and stroke risk and continued anticoagulation after successful atrial flutter ablation might therefore be warranted.

A Story of Migrating Azygous Vein

SESSION TITLE: Student/Resident Case Report Poster - Cardiovascular Disease II SESSION TYPE: Student/Resident Case Report Poster PRESENTED ON: Tuesday, October 25, 2016 at 01:30 PM - 02:30 PM INTRODUCTION: Azygous continuation of IVC is a rare anomaly and reported incidence is < 0.3 % in general population1. This anomaly is associated with atrial flutter1, increased incidence of lower extremity deep vein thrombosis1 and asplenia/polysplenia syndromes2. CASE PRESENTATION: A 50-year-old Caucasian male presented with worsening dyspnea and fatigue and was found to be in typical atrial flutter with 2:1 block. Flutter ablation was attempted by a femoral venous access but later the procedure was abandoned due to difficulty in advancing catheter into the right atrium. CT scan of the chest with 3-D reconstruction showed retrocrural continuation of inferior vena cava (IVC) as azygous vein (AZV); passing behind the aorta and draining into the coronary sinus (CS) [Figures 1, 2 and 3]. We used CT angiography with 3-D rendition to plan access. The patient subsequently underwent successful atrial flutter ablation with placement of a diagnostic catheter into the CS and right atrial cavotricuspid isthmus (CTI) via the IVC/AZV and placement of an ablation catheter to the CTI through the left subclavian vein. He was discharged in sinus rhythm on dofetilide and warfarin. DISCUSSION: The unusually large AZV can be confused with retrocural adenopathy or right-sided paratracheal mass2. It has been reported with Scimitar syndrome3 and non-compaction cardiomyopathy4. Recognition of this anatomic anomaly is of paramount importance in invasive procedures like radiofrequency catheter ablation and during cardiopulmonary bypass. CONCLUSIONS: A high index of suspicion shoud be present for patients requiring ablation procedures if operator feels a resistance during procedure and use of sophisticated imaging is definitely helpful recognizing this abnormality and can be helpful in avoiding complications.Our case is unique because AZV drained directly into the coronary sinus which has not been reported before in literature to our knowledge so far. Reference #1: Mamidipally S, Rashba E, McBrearty T, Poon M. Azygous continuation of inferior vena cava. J Am Coll Cardiol. 2010; 56(21):e41. Reference #2: J. Edward Bass, MD, Michael D. Redwine, MD, Larry A. Kramer, MD, Phan T. Huynh, MD, John H. Harris Jr, MD, DSc. Spectrum of Congenital Anomalies of the Inferior Vena Cava: Cross-sectional Imaging Findings. RadioGraphics, 2000; 20,639-652. Reference #3: Celik M, Celik T, Iyisoy A, Ayten O. Scimitar syndrome and azygos continuation of the inferior vena cava diagnosed in an adult--an unusual association. Congenit Heart Dis. 2012: E85-8. DISCLOSURE: The following authors have nothing to disclose: Ali Ghani, Sadaf Mirrani, Ghazi Mirrani, Rizwan Sardar, Ahsan Raza No Product/Research Disclosure Information

Interatrial Conduction Time Can Predict New‐Onset Atrial Fibrillation After Radiofrequency Ablation of Isolated, Typical Atrial Flutter

Many patients with successful atrial flutter (AFL) ablation will develop atrial fibrillation (AF) during follow-up. This study aimed to determine whether prolonged interatrial conduction time (IACT) is associated with risk for new-onset AF after ablation of isolated, typical AFL. Participants were 80 consecutive patients who underwent successful radiofrequency ablation of isolated, typical AFL from 2004 to 2012. Patients with any history of AF prior to AFL ablation were excluded. IACT was defined as the interval from the earliest onset of the P-wave on the ECG to the latest activation in the coronary sinus catheter during sinus rhythm measured after AFL ablation. New-onset AF was identified from 12-lead ECGs, 24-hour ambulatory monitoring, and device interrogations. During a mean follow-up of 4.1 ± 2.5 years after successful AFL ablation, 22 patients (27.5%) developed new-onset AF. Cox regression multivariate analysis demonstrated that IACT was the independent predictor of new-onset AF after AFL ablation (hazard ratio: 1.03; 95% confidence interval: 1.00-1.06; P = 0.02). IACT was accurate in predicting new-onset AF (AUC = 0.70). The optimal cut-off point of IACT for predicting new-onset AF was 120 milliseconds (sensitivity 47.6%, specificity 89.8%). Kaplan-Meier curves showed that new-onset AF after AFL ablation was significantly higher in patients with IACT ≥120 milliseconds than in patients with IACT< 120 milliseconds (P = 0.0016). Prolonged IACT predicted new-onset AF after ablation of isolated AFL. This finding may contribute to guiding decisions regarding the maintenance of anticoagulation after AFL ablation.

Successful ablation of atrial flutter in an adult patient post TOF repair

Successful ablation of atrial flutter in an adult patient post TOF repair

Abstract 17452: Inter-atrial Conduction Time Can Predict New-onset Atrial Fibrillation After Radiofrequency Ablation of Isolated, Typical Atrial Flutter

Introduction: Previous studies showed inter-atrial conduction delay (IACT) is an important electrophysiological factor predicting atrial fibrillation (AF) after successful atrial flutter (AFL) ablation. To the best of our knowledge, there has no previous study regarding the prognostic value of IACT as a predictor of new-onset AF after AFL ablation without AF history. Hypothesis: The purpose of this study was to determine the incidence and predictors of new-onset AF after Radiofrequency ablation (RFA) of isolated AFL in a retrospective cohort study. Methods: This study included consecutive patients who underwent successful RFA of isolated, typical AFL from 2004 to 2012. Patients with any history of AF prior to AFL ablation were excluded. IACT was defined as the interval from the onset of P-wave in 12-lead electrocardiogram to atrial intracardiac electrogram at the distal coronary sinus catheter. Results: Eighty patients were included in this study. During a mean follow-up 3.4±2.6 years after successful AFL ablation, 22 patients (27.5%) developed new-onset AF. A Cox regression multivariate analysis demonstrated that IACT was the independent predictor of new-onset AF after AFL ablation (odds ratio: 13.3; 95% confidence interval: 1.36-152.5; p=0.0255). IACT was accurate in predicting new-onset AF (AUC=0.70). The optimal cut-off point of IACT for predicting new-onset AF was ≧120ms, with a sensitivity of 0.476 and a specificity of 0.898. Kaplan-Meier curves showed that new-onset AF after AFL ablation was significantly higher in the patients with IACT ≧120ms compared to the patients with IACT&lt; 120ms (p=0.0016). Conclusions: IACT is an independent risk factor for new-onset AF after AFL ablation without a history of AF.

Abstract 16715: Incidence of Atrial Fibrillation After Atrial Flutter Ablation: A Meta-analysis Study

Background: Atrial Flutter (AFL) is usually initiated with short bursts of Atrial Fibrillation (AF). The incidence rate of AF after AFL ablation is variable. We evaluated the occurrence of AF in patients who underwent successful AFL catheter ablation with documented prior AF versus no prior AF. Methods: A meta-analysis was performed by searching online databases from January 1996 to April 2015 for studies describing patients who underwent typical AFL catheter ablation with and without prior AF. Results: A total of 36 articles were included, describing 6567 patients with typical AFL (2753 with prior AF and 3814 with no prior AF) who underwent ablation with 95% average success rate (bidirectional block). The overall incidence of AF after ablation was 35.3% (41% prior to ablation) during mean weighted follow-up (f/u) duration of 29.4 months. AF incidence after AFL ablation was 23% in patients with no prior AF and 52% in those with prior AF (OR 3.96, 95% CI [3.174.95] ; p&lt;0.00001). Subgroup analysis based on duration of f/u showed a significant variation of this probability (p=0.0003) between the group with &lt; 2 years f/u, compared to &gt; 2 years f/u due to an increase of AF incidence rate in patients with no prior AF. In studies with &lt; 2 years f/u duration, AF weighted average incidence rate after AFL ablation was 53.6 % in patients with prior AF and 14.3% in those with no prior AF (OR 6.90, 95% CI [4.5410.48] ; p&lt;0.00001). In studies with &gt; 2 years f/u duration, post-ablation AF developed in 51.3% of those with prior AF and in 26.3% of those with no prior AF (OR 2.93, 95% CI [2.423.56] ; p&lt;0.00001). Figure 1 Conclusions: Patients with prior history of AF have a higher incidence of AF after AFL ablation when compared to patients with no prior history of AF. However, this significantly decreases with extended follow-up duration due to an increase of detected AF in patients with no prior history of AF. This finding is important for decisions regarding anticoagulation plan after successful AFL ablation.

Is safe to discontinue anticoagulation after successful ablation of atrial flutter?

Is safe to discontinue anticoagulation after successful ablation of atrial flutter?

Abstract 19766: Prediction of Clinical Atrial Fibrillation induced during Typical Atrial Flutter Ablation

Background: Atrial fibrillation (AF) and isthmus dependent atrial flutter (AFL) are two separate entities that in many patients coexist. We sought to investigate whether AF inducibility (spontaneous or drug induced) during isthmus AFL ablation predicted the occurrence of AF at follow up after successful AFL ablation. Methods: Two hundred seventy three consecutive patients with isthmus dependent AFL undergoing ablation of AFL at our institution were enrolled in this study. 119 (43%) patients were excluded since they had evidence of AF prior to AFL ablation. Univariate and multivariate analyses were performed. Results: A total of 154 patients (male: 72%, age: 61 ±13) with AFL and without history of AF composed our patient population. All patients underwent successful AFL ablation. During ablation, AF was induced in 28 (18%) patients. After a mean follow up of 34 ± 23.5 months a total of 50 (32%) experienced AF. Univariate and multivariate analyses showed that only age and AF inducibility during AFL ablation were predictors of AF. Univariate analysis (age: p=0.038 and inducible AF p=0.032 and multivariate analysis (age: p=0.011 inducible AF: p=0.016) ) with and adjusted odds ratio of 3.3 [95% CI (1.250-8.676)] (Table 1). A total of 169 (62%) patients experienced AF before or after AFL ablation. Conclusion: AF inducibility in patients undergoing isthmus dependent AFL without history of AF is a strong predictor of AF recurrence. This has an important clinical relevance on anticoagulation management of these patients.

A new methodology for atrial flutter ablation by direct visualization of cavotricuspid conduction with voltage gradient mapping: a comparison to standard techniques

To demonstrate that critical conduction within the cavotricuspid isthmus (CTI) can be directly visualized by voltage gradient mapping and facilitate efficient ablation compared to standard techniques. Group 1 (1 operator, n = 11) ablated based upon contact voltage measurements and voltage gradient mapping. Ablation targeted low-voltage bridges (LVBs) within the CTI. Repeat maps were obtained following ablation. Group 2 (operators 2, 3, and 4 n = 35) utilized electroanatomic navigation and ablated by the creation of linear lesions from the tricuspid valve to the inferior vena cava. Demonstration of bidirectional block (BDB) was required in both groups. LVB were associated with CTI conduction in all Group A patients. LVB ablation terminated flutter, or created BDB. Following ablation, CTI voltage connections were absent in all patients. Compared with Group B, Group A had less radiofrequency (RF) lesions to atrial flutter (AFL) termination (P = 0.001), less total RF lesions (P = 0.0001), and less total RF time (P = 0.001). Group 1 had no recurrent AFL whereas Group 2 had three recurrences. (follow-up median of 231 ± 181 days). (i) Voltage gradient mapping visualized regions of critical CTI conduction, (ii) ablation of LVB terminated AFL and resulted in BDB, (iii) repeat mapping confirmed the absence of trans-isthmus voltage, and (iv) Compared with standard ablation, voltage gradient mapping decreases total RF lesions, lesions to AFL termination, and total RF time. Use of voltage gradient mapping can facilitate successful AFL ablation.

Risk of stroke and atrial fibrillation after radiofrequency catheter ablation of typical atrial flutter

Studies suggest that 18%-50% of the patients develop atrial fibrillation (AF) after typical atrial flutter (AFL) ablation. However, little data exist about the incidence of and risk factors for stroke and AF after successful ablation of typical AFL. To determine the risk of stroke and AF after radiofrequency ablation of typical AFL. A retrospective review of patients undergoing AFL ablation between 2002 and 2010 was performed to determine the incidence of and risk factors for stroke and AF after successful ablation of typical AFL. The study cohort consisted of 126 patients (age 66 ± 10 years) with a mean follow-up of 40 ± 30 months after ablation. Following successful AFL ablation, AF occurred in 46 patients (37%), with an incidence of 104 cases of documented AF per 1000 person-years after AFL ablation. Twenty patients (16%) developed new AF after AFL ablation. Stroke occurred in 8 patients (6%) during follow-up, with an incidence of 21 strokes per 1000 person-years. Six of the 8 patients (75%) with strokes had documented AF occurrences after AFL ablation. The presence of AF after AFL ablation was the only risk factor associated with the risk for future stroke. Patients with typical AFL undergoing successful ablation are at an elevated risk for AF and stroke following the procedure. Because postprocedure AF is the only identifiable risk factor for stroke, rigorous monitoring of patients after typical AFL may help identify those patients who are at an increased risk for stroke.

Sleep apnea does not predict atrial flutter recurrence after atrial flutter ablation

Sleep apnea (SA) has been associated with atrial fibrillation (AF) and has been found to be a predictor of AF recurrence after successful pulmonary vein isolation. No investigations have been carried out to determine the prevalence of SA in patients with typical atrial flutter (AFL) and the impact of SA on AFL recurrence after AFL ablation. Our aim is to determine if SA is a predictor of recurrence of AFL and/or atrial arrhythmias in patients who have undergone AFL ablation. This study used a retrospective electronic chart review analysis of consecutive right-sided isthmus-dependent AFL referred for ablation over a 2-year period. Recurrent atrial arrhythmias were classified as AFL, AF, or other arrhythmias. SA prevalence was determined. We included 122 consecutive patients undergoing AFL ablation between January 2008 and December 2009. Mean follow-up was 28.3 ± 6.4 months. Males were 75.4%, had a mean age of 68.3 ± 10.4 years, hypertension 65%, and structural heart disease 42%. Prevalence of SA was 27%. Recurrence of AFL was observed in 9.8%, recurrence of AF was observed in 22.1%, and other arrhythmias 4.9%. SA was not a predictor of AFL recurrence (6.1% vs. 11.2%; p = 0.39). SA was neither a predictor of AF nor of other arrhythmia recurrences. Variables associated with AFL recurrence were: no history of preablation antiarrhythmic drugs (18.8% vs. 6.7%; p = 0.04) and lower BMI (27.07 kg/m(2) vs. 30.87 kg/m(2); p = 0.04). Prevalence of SA in patients with AFL was 27%. SA was not found to be a predictor of AFL recurrence after successful AFL ablation.

Effects of AZD0837, a Novel Direct Thrombin Inhibitor, on the Electrophysiological Properties of the Human Heart

AZD0837 is an investigational oral anticoagulant that is bioconverted to its active form, AR-H067637, a selective direct thrombin inhibitor. The objectives of the present study were to investigate if there are any clinically relevant adverse effects of intravenous AZD0837 on cardiac conduction, refractoriness and repolarization, and to study its safety and tolerability. In this randomized, double-blind, parallel-group, placebo-controlled study (study code D1250C00026), invasive electrophysiological measurements were performed twice in 30 subjects with a history of, or ongoing, atrial flutter, starting 30 minutes after successful ablation of atrial flutter and then 60 minutes after start of an intravenous infusion of AZD0837. Pre-study warfarin therapy was not an exclusion criterion. The stimulation protocol was performed mainly at 500 and 400 ms drive cycle length. A 12-lead ECG was also recorded before and during AZD0837 infusion. Plasma concentrations of AZD0837 and its metabolites were obtained at predefined timepoints. Measurements were made at baseline and during stable plasma concentrations of the prodrug AZD0837 (mean +/- standard deviation 7.96 +/- 2.38 micromol/L, approximate target of 10 micromol/L), the intermediate metabolite AR-H69927 (1.26 +/- 0.39 micromol/L, target 1-2 micromol/L) and the active direct thrombin inhibitor AR-H067637 (0.35 +/- 0.14 micromol/L, target 0.5-1.0 micromol/L). There were no clinically relevant effects on cardiac conduction (QRS duration, PR interval, His bundle electrogram, Wenckebach point), refractoriness (atrial, atrioventricular and ventricular effective refractory periods) or repolarization (QT, QT interval corrected for heart rate using Fridericia's formula, QRS onset to the top of the T wave [QT(top)], QRS onset to the end of the T wave [QT(end)] or QT(top) - QT(end)). AZD0837 was well tolerated, and had no clinically relevant effects on cardiac electrophysiology of the target population, either in subjects previously treated with warfarin or in those without previous treatment.

A Randomized Invasive Cardiac Electrophysiology Study of the Combined Ion Channel Blocker AZD1305 in Patients After Catheter Ablation of Atrial Flutter

This study assessed the cardiac electrophysiological and hemodynamic effects of an intravenous infusion of the combined ion channel blocker AZD1305. After successful ablation of atrial flutter, patients were randomized to receive placebo (n = 12) or AZD1305 (n = 38) in 4 ascending dose groups. Electrophysiological and hemodynamic measurements were performed before and commencing 20 minutes after start of infusion. Left atrial effective refractory period increased dose and the primary outcome measure increased dose and plasma concentration dependently, with a mean increase of 55 milliseconds in dose group 3. There was a corresponding increase in right atrial effective refractory period of 84 milliseconds. The right ventricular effective refractory period and the paced QT interval also increased dose and concentration dependently, by 59 and 70 milliseconds, respectively, in dose group 3. There were indications of moderate increases of atrial, atrioventricular nodal, and ventricular conduction times. No consistent changes in intracardiac pressures were observed, but there was a small transient decrease in systolic blood pressure. Adverse events were consistent with the study population and procedure, and there were no signs of proarrhythmia despite marked delay in ventricular repolarization in some individuals. AZD1305 shows electrophysiological characteristics indicative of potential antiarrhythmic efficacy in atrial fibrillation.