Atypical Left Atrial Flutter Research Articles

Pulmonary vein isolation combined with a new protocol of linear ablation to treat persistent atrial fibrillation: a prospective cohort with 1 year follow-up

Abstract Background The clinical value of ablation strategies beyond pulmonary vein isolation (PVI) in patients with persistent atrial fibrillation (perFA) is not clearly established and the optimal strategy to cure perFA remains a challenge due to the high recurrence rate after PVI alone (up to 50% of patients during 1-year follow-up). Purpose To determine the additional therapeutic value of a new design of linear ablation in the left atrium (LA) added to PVI in patients with perFA. Methods In this prospective study consecutive patients with perFA were included and underwent PVI combined with a predefined homogeneous protocol of linear ablation in the LA: anterolateral line from the mitral annulus to the left superior pulmonary vein around the left atrial appendage, anteroseptal line and posterior wall isolation. Patients were followed during 12 months after ablation with daily 30 s single-lead ECG obtained with mobile applications. The main endpoint was the incidence of recurrences, defined as any documented, sustained (>30 s) episodes of atrial arrhythmia that occurred after a 3 months blanking period. Antiarrhythmic drugs were avoided after the blanking period. Results 59 patients were included (61 [IQR 53-69] years old, 76% male sex). Acutely successful PVI was achieved in all patients and the linear ablation protocol was performed in 52 (89,7%) patients. The linea ablation protocol was not completed in 6 patients due to the following reasons: repetitive AF triggering from the same PV in 2 patients, induction and successful focal ablation of left atrial flutter in 1 patient, respiratory failure in 1 patient with severe obstructive lung disease and excessively prolonged procedure time in 2 patients. 58 patients completed the 12 months follow-up period and 1 patient was lost due to end-stage heart failure. The survival free of atrial arrhythmia recurrences was 69.1% [95%CI 55.1-79.5] (Figure). No patient had recurrences of perAF (>7 days continuous AF). 9 (53%) patients had at least 1 episode of self-limited paroxysmal AF. In these patients the average paroxysmal AF burden during the follow-up was 24 hours/year [IQR 9-24 hours/year]. In another 8 (47%) patients the recurrent arrhythmia was atypical left atrial flutter exclusively The incidence of procedure-related complications was 6,9%: 1 pericardial bleeding, 1 acute pulmonary edema, 1 splenic infarction and 1 stroke); no patient died during the study period. Conclusions A combined strategy of PVI plus the specific linear ablation protocol used in this study is associated with a low rate of atrial arrhythmia recurrences and total absence of persistent AF after ablation. A randomized multicenter clinical trial is ongoing to validate these results.Ablation strategy.Kaplan-Meier curve: recurrences

Abstract 9947: Prospective Prediction of Left Atrial Flutter From Computer Simulation

Introduction: Atypical left atrial flutter (ALAF) is often the result of ablation treatment for AF. Many patients report a reduction in quality of life from AF to ALAF. If pharmacological rate control fails additional ablation can provide solutions. However, success rates are low due to difficulties in mapping all potential flutters accurately. Hypothesis: LGE-MRI can inform computation simulation to predict all possible ALAF pathways and increase the information available to the electrophysiologist. Methods: Informed and consented patients scheduled for ALAF ablation received an MRA and LGE-MRI. Fig1. From the MRA the left atrial wall was segmented and registered to the LGE-MRI. Scar and gray areas were estimated by threshold segmentation. The threshold was calculated with the intensity value ratio. The information was integrated into a monodomain model. Ionic currents were modeled according to Courtemanche with a reduction of some conductance in fibrotic regions. To induce ALAF S1S2 pacing was done with an S1 cycle length of 600ms and S2 decreased from 250 to 170ms. Induction was tested at 10 different locations. Results were provided to the electrophysiologist. Results: Prospective prediction of the ALAF pathway for six patients was successful and the clinically observed flutter was predicted. Fig. 2) shows the value of the prediction, electroanatomic mapping was inconclusive even unable to exclude the right side. Ablation on the right side did not alter the flutter, but ablation near the mitral valve. Conclusions: We successfully predicted clinically observed ALAF pathways. The next step is to find ablation points for all predicted pathways.

Radiofrequency ablation of the left atrial scar-related atrial flutter in a patient without prior ablative procedures

Atypical atrial flutter may develop in patients without prior cardiac ablations. In such cases, they may be related to the areas of spontaneous left atrial scarring. We describe a case report of a patient with atypical left atrial flutter with areas of spontaneous left atrial scarring adjacent to the mitral valve annulus.

Detectable reentrant circuits in localized microreentrant tachycardias in the era of ultra high-density mapping

Abstract Funding Acknowledgements Type of funding sources: None. Background Optimal criteria in clinical practice differentiating microreentrant atrial tachycardias (mAT) from macroreentrant atrial arrhythmias (MAT) have not yet been clarified. The use of multielectrode catheters and the recent development of ultra high-density mapping (UHDM) with automated features has improved our knowledge of mAT circuits and foci location. Purpose In the present study, we systematically evaluated AT mechanisms in a large consecutive cohort of patients with MAT identifying the precise mAT circuits using the Rhythmia mapping system. Methods Consecutive patients indicated for MAT ablation from January 2021 to November 2021 at 33 centers were prospectively included. All MATs were completely mapped in the left or right atrium by means of the Rhythmia mapping system and the 64-poles Orion basket catheter. For study purpose, a mAT was defined as an AT with slow continuous low fragmented potentials covering at least 50% of tachycardia cycle length (CL) in a small area (set as a circuit within < 1 cm2) and in a couple of closed splines of the Orion catheter and a centrifugal activation pattern to the remainder of the atria. The Lumipoint tool was systematically used to confirm EGM fragmentation inside this area. Data are reported as mean±SD. Results One-hundred eighty-seven MATs were analyzed: 100 (53.7%) atypical left atrial flutter, 27 (14.3%) left AT and 60 (32%) right AT. A total of 7 MAT (prevalence of 3.7%) was identified as mATs (6 atypical left atrial flutter and 1 AT), with 5 out 7 with a previous history of AF ablation procedure. The percentage of atrial surface with a voltage level below 0.1 mV was 19±17%. The CL was 329±78ms. The electrical activity spanning the whole CL was detected by 2±0.6 pairs of close bipoles of the Orion catheter, and was actually confined to a region of 0.4±0.2cm2 with continuous highly fractionated potential covering 68±10% of the CL (longest component of fractionated EGM per spline=74±18% of the CL). Voltage level was 0.3±0.1mV at RF delivery site and 0.2±0.1mV at the site of longest duration of the fragmented potential, respectively. Targeted mAT activity was identified closer to PVs in three cases and at the mid portion of the anterior wall and at the roof in two cases each, respectively. In all cases a single shot RF delivery terminated each arrhythmia at targeted location. Consolidative RF ablations were then delivered in the adjacent area. No complication occurred. At three months follow-up all patients remained free from any AT recurrence. Conclusions In this standard of care clinical experience with UHDM system, the prevalence of mAT seems to be higher than previously reported in literature. A technique based on mAT identification through a novel automated algorithm and matched area of electrogram fractionation captured by the Orion catheter may limit the extent of ablation needed.

Catheter ablation of complex atrial tachyarrhythmias in adult patients with cor triatriatum.

Reports concerning clinical characteristics of cor triatriatum and approaches for catheter ablation of complex atrial tachyarrhythmias remain limited. Here, we describe successful catheter ablation treatments for complex atrial tachyarrhythmias in patients with cor triatriatum and address the clinical caveats. Demographic characteristics, electrophysiologic findings, and ablation results in four patients with cor triatriatum were described. Catheter ablation was performed in four patients with cor triatriatum (three sinister and one dexter) and complex atrial arrhythmias (three with persistent atrial fibrillation (AF) and one with atypical left atrial flutter). A transseptal puncture was selectively directed into the accessory compartment containing the pulmonary veins. A comprehensive preview involving transthoracic echocardiography, transesophageal echocardiography, and computed tomography of the pulmonary veins was critical for proper positioning of ablation catheters. The pulmonary veins remain the major triggers or initiators for AF, and four pulmonary vein isolation procedures were sufficient to achieve successful results with negative inducibility test in the patients with AF. Heterogeneous conduction and complex fractionated signals were observed on the fibromuscular membrane. Atypical flutter was terminated during ablation over the connection between membrane and left atrial roof. The procedure was successfully performed on all patients without complications. No acute recurrences of atrial tachyarrhythmias were observed in any of the patients during short-term follow-up. Catheter ablation is a feasible and efficient therapeutic strategy for treating complex atrial tachyarrhythmias in patients with cor triatriatum. Atrial remodeling due to anatomical obstruction or heterogeneous conduction of the fibromuscular membrane may serve as an arrhythmic substrate.

Catheter ablation of atrial arrhythmias in patients after thoracoscopic ablation of persistent atrial fibrillation

Aim. To determine the mechanisms of development and approaches to interventional treatment of postoperative atrial tachycardia in patients after thoracoscopic ablation (TA) of atrial fibrillation (AF). Material and methods . The results of thoracoscopic ablation of AF in 46 patients were analyzed, of which 19,5% (n=9) had atrial tachycardia after the procedure. Radiofrequency ablation (RFA) was conducted in these patients after a 3-month blanking period. Regardless of tachycardia type, the threedimensional reconstruction including high-density right and left atrial (LA) voltage mapping was performed in order to visualize the lesions, pulmonary veins and LA posterior wall isolations. After RFA and sinus rhythm restoration, re-mapping was performed to assess conduction block and absence of electrical activity in the lesion zones. Results. Complete pulmonary vein (PV) isolation was verified in 55,5% of patients (n=5). In 44,4% (n=4), there were residual PV fractionated potentials without conduction with LA. In 22,2% of subjects (n=2), we identified typical atrial flutter (AFL), which was terminated by RFA in cavotricuspid isthmus (CTI). There were 77,7% (n=7) of patients who were diagnosed with atypical LA flutter; 66,6% (n=6) of them had conduction reconnection at the thoracoscopic box-lesion line. Perimitral AFL with slow conduction zone which was located on the anterior wall of LA was verified in 11,1% of patients (n=1). The effective RFA was performed in these areas. Two main factors affecting failed ablation were LA volume and body mass index (BMI). In patients with arrhythmias after TA, LA volume was 180,2±35,6 ml vs 158,34±38,5 ml in patients with sinus rhythm. BMI was 30,8±3,1 kg/m2 and 28,9±3,9 kg/m2, respectively. The mean follow-up was 9,8±2,7 months. All patients after catheter ablation maintained a stable sinus rhythm. Conclusion. Atrial tachycardia after TA is caused by the gaps in box-lesion lines. The main predictors of gaps are high values of LA volume and BMI. The high-density mapping increases the effectiveness of RFA. Combination of epicardial and endocardial accesses is the most effective approach to treatment of patients with persistent AF.

THE USE OF THE NEW NAVIGATION SYSTEM “ASTROCARD” (RUSSIA) WITH THE ABILITY TO INTEGRATE THE COMPUTER MODEL OF THE LEFT ATRIUM FOR THE TREATMENT OF ATRIAL FIBRILLATION AND FLUTTER

Aim. The first experience of the application of the integration algorithm for computed tomography of the heart with the navigation system “Astrocard” (Russia) when performing radiofrequency ablation in patients with atrial fibrillation and flutter.Material and Methods. A total of 31 patients with atrial fibrillation and two patients with atypical left atrial flutter were subjected to electroanatomical reconstruction of the left atrium and pulmonary veins with computed tomography of the heart. In patients with atrial fibrillation, an ablation scheme involved for antral isolation of the pulmonary veins. In patients with atypical left atrial flutter, linear ablation was applied in the area of slow conduction. The duration of the operation was 58±14.5 min, and the time of fluoroscopy was 33±8 min.Conclusion. The merge function of the “Astrocard” navigation mapping system (Russia) provided an accurate comparison of the electroanatomical map with the computed tomography of the heart, which allowed us to minimize the time of fluoroscopy and the time of operation.

Радиочастотная аблация атипичного левопредсердного трепетания после изоляции устьев легочных вен

Радиочастотная аблация атипичного левопредсердного трепетания после изоляции устьев легочных вен

Atypical Left Atrial Flutter Following Aortic Valve Surgery

Atypical Left Atrial Flutter Following Aortic Valve Surgery

Detached tip of a transseptal sheath during left atrial ablation

Left atrial ablation has become more commonplace with the advent of catheter ablation for atrial fibrillation. A number of transseptal sheaths have been produced to enhance safe and efficient catheter manipulation in the left atrium (LA) for these procedures. Some of the sheaths have been subject to recall due to partial or complete detachment of its radiopaque tip. We report a case of a 46 year-old female diagnosed with idiopathic dilated cardiomyopathy that presented with atypical left atrial flutter. During electrophysiologic study, a Swartz braided SL1 (SL-1) transseptal sheath was used to introduce the ablation catheter to the left atrium. During left atrial mapping, the radiopaque tip of the sheath detached from the rest of the sheath and was seen floating in the LA. After exchanging the SL-1 sheath with a deflectable sheath, the detached segment was retrieved out of the LA and eventually out of the vascular system using an angioplasty balloon advanced over a wire and inflated distal to the lumen of the detached tip. The root cause of this malfunction was found to be lack of a secondary bonding process that these sheaths generally undergo during the manufacturing process. We describe the case of a left atrial ablation procedure where a novel percutaneous method was able to successfully retrieve the detached tip of a transseptal sheath from the vascular system, thereby avoiding a potential catastrophic complication or thoracotomy. This method may be useful in other cases where similar circumstances may present.

Circumferential Pulmonary Vein Ablation With Additional Linear Ablation Results in an Increased Incidence of Left Atrial Flutter Compared With Segmental Pulmonary Vein Isolation as an Initial Approach to Ablation of Paroxysmal Atrial Fibrillation

There has been growing concern that linear ablation is associated with an increased risk of iatrogenic arrhythmias in patients undergoing ablation for atrial fibrillation (AF). Therefore, we compared circumferential pulmonary vein ablation plus left atrial linear ablation (CPVA+LALA) with segmental pulmonary vein isolation (PVI)in patients with paroxysmal AF. Sixty-six consecutive patients with paroxysmal AF were prospectively randomly assigned to receive PVI versus CPVA+LALA (consisting of encircling lesions around the pulmonary veins), a roof line, and a mitral isthmus line with documentation of bidirectional mitral isthmus block. All patients were seen at 1, 3, 6, and every 12 months after ablation, with 14-day continuous ECG monitoring every 6 months. At 16.4+/-6.3 months after 1 ablation procedure, 19 patients (58%) remained free of atrial arrhythmias after PVI versus 17 patients (51%) after CPVA+LALA (P=0.62). After PVI, 14 patients had recurrent paroxysmal AF, whereas after CPVA+LALA, 8 patients had recurrent AF, 6 had atypical left atrial flutter (LAFL), and 2 had both AF and LAFL (P=0.32 between PVI versus CPVA+LALA for AF but P=0.002 for LAFL). Twenty-eight patients (85%) remained arrhythmia-free after 1.3+/-0.5 PVI procedures versus 28 patients (85%) after 1.4+/-0.6 CPVA+LALA procedures (P=NS). Fluoroscopy time was longer after CPVA+LALA versus PVI (91 versus 73 minutes, P=0.04). As an initial ablation approach in patients with paroxysmal AF, more LAFL occurred after CPVA+LALA and fluoroscopy times were longer compared with segmental PVI.

Electro-Anatomic (CARTO) Mapping for Measurement of Left Atrial Volume: Validation Against Real-Time 3D Echocardiography

Background: Left atrial size is a determinant of atrial fibrillation ablation efficacy and embolic risk. The recent advent of real-time full-volume 3DE allows now rapid measurement of chamber volume more accurately than with stan- dard two-dimensional echocardiography as volume is reconstructed from endocardial contours of the entire chamber without making geometric assumptions. Electro-anatomic (CARTO) mapping allows measurement of chamber volume during the ablation procedure of atrial arrhythmias, but has never been validated for measuring left atrial size against three-dimensional echocardiography (3DE). Our aim was to compare left atrial volume measured using CARTO with that measured by real-time 3D echocardiography. Methods: 37 patients undergoing CARTO-guided radiofrequency ablation for atrial fibrillation or atypical left atrial flutter were studied and left atrial volume measured by mapping 73+17 points. Full-volume transthoracic real-time 3-D echocar- diography was performed within 24 hours in each patient, and end-systolic left atrial volume measured offline. Results: Left atrial volume measured using CARTO correlated well with that using 3D echocardiography (r = 0.78, p<0.001), but electro-anatomic mapping consistently yielded greater values (mean difference of 33+19cc). Conclusion: Left atrial volume measured by CARTO correlates well with that obtained by real-time 3D echocardiogra- phy, although the former technique consistently yields larger values.

Localizing circuits of atrial macroreentry using electrocardiographic planes of coherent atrial activation

The complexity of ablation for atrial macroreentry atrial flutter (AFL) varies significantly depending on the circuit location. Presently, surface electrocardiogram (ECG) analysis poorly separates left from right atypical AFL and from some cases of typical AFL, which delays diagnosis until invasive study. The purpose of this study was to differentiate and localize the intra-atrial circuits of left atypical AFL, right atypical, and typical AFL using quantitative ECG analysis. We studied 66 patients (54 men, age 59 +/- 14 years) with typical (n = 35), reverse typical (n = 4), and atypical (n = 27) AFL. For each, we generated filtered atrial waveforms from ECG leads V5 (X-axis), aVF (Y-axis), and V1 (Z-axis) by correlating a 120-ms F-wave sample to successive ECG regions. Atrial spatial loops were plotted for three orthogonal planes (frontal, XY = V5/aVF; sagittal, YZ = aVF/V1; axial, XZ = V5/V1) and then cross-correlated to measure spatial regularity (i.e., coherence; range -1 to 1). Mean coherence was greatest in the XY plane (P <10(-3) vs. XZ or YZ). Atypical AFL showed lower coherence than typical AFL in the XY (P <10(-3)), YZ (P <10(-6)), and XZ (P <10(-5)) planes. Atypical left AFL could be separated from atypical right AFL by lower XY coherence (P = .02); for this plane, coherence <0.69 detected atypical left AFL with 84% specificity and 75% sensitivity. F-wave amplitude alone did not separate typical, atypical right, or atypical left AFL (P = NS). Atypical AFL shows lower spatial coherence than typical AFL, particularly in the sagittal and axial planes. Coherence in the Cartesian frontal plane separated left and right atypical AFL. Such analyses may be used to plan ablation strategy from the bedside.