Focal atrial tachycardia originating from the epicardial left atrial appendage

Combination of electrophysiological mapping, radiofrequency catheter ablation, and atrial appendectomy in a 5-year-old girl with tachycardia-induced cardiomyopathy: a case report

BACKGROUND

Atrial tachycardia (AT) originating from the left atrial appendage (LAA) is uncommon and the most difficult arrhythmia to eliminate. Therefore, we present the case of a 5-year-old girl with tachycardia-induced cardiomyopathy (TIC) caused by AT originating from the LAA and successfully treated with RFCA associated to left atrial appendectomy. With resolution of AT, we observed a progressive improvement of LV function. The effectiveness and safety of this combination therapy were evaluated over a one-month follow-up period.

CASE PRESENTATION

A 5 -year-old female was evaluated for three days of incessant cough and a syncopal episode. Surface echocardiography and 24-hour monitoring showed that the infant had persistent atrial tachycardia. Echocardiography revealed an enlarged tele diastolic diameter (46.1 mm) and malfunctioning (EF 28.53%) left ventricle. The location of the lesion at the apex of the LAA was further confirmed by electrophysiological study and RFCA. After RFCA, the infant's ECG monitor showed that sinus rhythm was maintained for up to 22 h. Subsequently, atrial tachycardia recurred and sinus rhythm disappeared. Finally, atrial appendectomy was performed and sinus rhythm returned to normal.

CONCLUSIONS

The heart function of the infant improved and sinus rhythm was maintained, further demonstrating the safety and effectiveness of combined treatment with RFCA and atrial appendectomy after electrophysiological localization of AT from LAA to TIC.

Repeat catheter ablation for atrial fibrillation

Catheter ablation of atrial fibrillation (AF) is an established therapy that reduces AF burden, improves quality of life, and reduces the risks of cardiovascular outcomes. Although there are clear guidelines for the application of de novo catheter ablation, there is less evidence to guide recommendations for repeat catheter ablation in patients who experience recurrent AF. In this review, we examine the rationale for repeat ablation, mechanisms of recurrence, patient selection, optimal timing, and procedural strategies. We discuss additional important considerations, including treatment of comorbidities and risk factors, risk of complications, and effectiveness. Mechanisms of recurrent AF are often due to non-pulmonary vein (non-PV) triggers; however, there is insufficient evidence supporting the routine use of empiric lesion sets during repeat ablation. The emergence of pulsed field ablation may alter the safety and effectiveness of de novo and repeat ablation. Extrapolation of data from randomized trials of de novo ablation does not optimally inform efficacy in cases of redo ablation. Additional large, randomized controlled trials are needed to address important clinical questions regarding procedural strategies and timing of repeat ablation.

Left atrial appendage doppler velocity as a predictor of recurrence of atrial fibrillation after transesophageal echocardiogram guided electrical cardioversion

Background

There is a paucity of data on average left atrial appendage emptying velocity (LAAV) measured by doppler during transesophageal echocardiogram (TEE) being able to predict the risk of AF recurrence after electrical cardioversion (ECV).

Methods

Using electronic medical records from a community hospital, retrospective study was conducted after identifying all patients that received TEE-guided ECV. Data pertaining to LAAV, AF recurrence, and variables were obtained and analyzed.

Results

Out of 625 patients receiving TEE-guided ECV, 94 were excluded, and 51 did not convert to sinus rhythm. 480 patients had a successful ECV; out of these, 201 (41.87%) and 243 (50.62%) had a recurrence of atrial fibrillation at the end of 1 month and 3 months, respectively. Low LAAV (<=30 cm/s) was independently associated with an increased risk of AF recurrence at the end of 1 month (aOR 2.37, 95CI 1.5-3.73; p < 0.001) and 3 months (aOR 2.51, 95CI 1.59-3.96; p < 0.001) after TEE-guided ECV.

Conclusions

Low LAAV is associated with a high risk of AF recurrence. Identifying a specific subgroup of individuals at high risk of AF recurrence with the help of pre-ECV LAAV will facilitate the early institution of alternate treatment strategies and the plan for additional therapies.

Epicardial ablation of refractory focal atrial tachycardia after a failed endocardial approach

BACKGROUND

Endocardial ablation is effective for most focal atrial tachycardias (FATs). In rare circumstances, the FAT can originate from the epicardial side of the atrium.

OBJECTIVE

In the present study, we retrospectively assessed the percutaneous approach for epicardial ablation of FAT when standard endocardial ablation had failed.

METHODS

Among a consecutive 186 patients undergoing ablation for 198 FATs, epicardial mapping and ablation via a percutaneous subxiphoid approach were attempted in 10 patients because of failed endocardial ablation.

RESULTS

In 3 cases, the origin of FAT was at the epicardial side of the junction of the right atrial appendage and superior vena cava. In 3 cases, the origin of FAT was located in the epicardial region of the left atrial insertion of Bachmann bundle. In 2 cases, the FAT originated from the epicardial side of the right atrial free wall. In 1 case, the FAT was successfully ablated from the epicardial side of the right atrial appendage, and in the remaining case, the origin of FAT was located in the epicardial region of the vein of Marshall. All FATs were successfully eliminated by ablation at the epicardial earliest activation site.

CONCLUSION

Epicardial mapping and ablation can be considered as an effective and safe option for FAT resistant to endocardial ablation.

Stroke prevention of thoracoscopic left atrial appendage clipping in patients with non-valvular atrial fibrillation at high risk of stroke and bleeding: study protocol for a non-randomised controlled clinical trial

INTRODUCTION

Non-valvular atrial fibrillation (NVAF) is a high-risk factor for ischaemic stroke. The 2016 European Society of Cardiology Atrial Fibrillation Management guidelines recommend oral anticoagulants (OACs) to prevent stroke in men with CHA₂DS₂-VASc scores ≥2 and women ≥3. However, in patients with a high risk of stroke and a high risk of bleeding (HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (> 65 years), Drugs/alcohol concomitantly) score≥3), OAC had a higher risk of bleeding. Left atrial appendage closure (LAAC) is non-inferior to OAC as a means of preventing stroke in several studies. As a minimally invasive intervention to prevent stroke, transthoracic LAAC (TS-LAAC) has a high successful closure rate, but there is a lack of literature reports directly comparing it with OAC. Our research compares TS-LAAC with novel oral anticoagulants (NOACs) and provides an appropriate programme for stroke prevention in a specific population.

METHODS AND ANALYSIS

This is a non-randomised controlled trial study protocol, and we will conduct this study from April 2022 to April 2025. The study included 186 patients with confirmed NVAF, 93 of whom completed thoracoscopic LAAC, and the control group treated with NOACs. The primary outcome was the incidence of stroke and systemic embolism, as well as the composite endpoint events (stroke, systemic embolism, myocardial infarction, bleeding, cardiovascular death, etc). Secondary outcomes were ischaemic stroke, haemorrhagic stroke, any bleeding events, death from cardiovascular causes, death from all causes, residual root rate in the surgery group, device-related thrombosis in the surgery group, changes in blood pressure, cardiac chamber size changes, etc. Each subject completed at least 1 year of follow-up.

ETHICS AND DISSEMINATION

The study has been approved by the Medical Ethics Committee of Beijing Tiantan Hospital, Capital Medical University, China (approval number: KY2022-013-02). The results from this study will be disseminated through manuscript publications and national/international conferences.

TRIAL REGISTRATION NUMBER

ChiCTR2200058109.

Left atrial appendage flow velocity predicts recurrence of atrial fibrillation after catheter ablation: A systematic review and meta-analysis

Purpose

There is increasing evidence that left atrial appendage flow velocity (LAAFV) is linked to the recurrence of atrial fibrillation (AF) after catheter ablation (CA), suggesting the potential predictable significance of LAAFV in this setting. We performed a systematic review and meta-analysis to assess whether LAAFV is association with AF recurrence after CA.

Methods

Up to May 1, 2022, six databases (PubMed, EMBASE, Web of Science, Cochrane Library, Scopus, and CINAHL) were searched for literature reporting the association between LAAFV and AF recurrence after CA. All statistical analyses were carried out using STATA version 16 software. Heterogeneity was determined by the Cochrane’s Q test and I² statistics. The Newcastle-Ottawa Scale (NOS) was used to assess the methodological quality of each included study, and the Grading of Recommendations Assessment, Development and Evaluation (GRADE) method was adopted to evaluate the quality of evidence.

Result

Sixteen studies with 5,006 AF patients after CA (1,479 patients with AF recurrence, 3,527 without AF recurrence) were included in the meta-analysis. The meta-analysis of 15 studies (16 data sets) showed that patients with recurrence exhibited lower LAAFV values than those without recurrence [standardized mean difference (SMD): −0.65, 95% CI: −0.88 to −0.42, P < 0.01]. Moreover, we evaluated the association of LAAFV and the risk of AF recurrence after CA. Nine studies (11 data sets) defined LAAFV as continuous variables, and the pooled analysis suggested that for every 1 cm/s rise in LAAFV values, the risk of AF recurrence after CA decreased by 3% [Odds Ratio (OR): 0.97, 95% CI: 0.95 to 0.99, P < 0.01]. Seven studies defined LAAFV as categorical variables, and the pooled analysis showed that lower LAAFV were associated with an increased risk of AF recurrence after CA [OR: 2.28, 95% CI: 1.46 to 3.57, P < 0.01]. The subgroup analyses showed that the association between LAAFV and AF recurrence after CA was not significantly affected by the AF type and ablation procedure. The NOS indicated that included studies were moderate to high quality, while the GRADE assessment suggested a low certainty of the evidence.

Conclusion

Lower LAAFV may be associated with an increased risk of AF recurrence after CA. Further studies with well designed and randomized studies for LAAFV should be conducted.

Systematic review registration

[https://www.crd.york.ac.uk/PROSPERO/], identifier [CRD42022333627].

Epicardial Termination of Left Atrial Appendage Atrial Tachycardia

This case report describes a third successful attempt to ablate a focal atrial tachycardia originating from the left atrial appendage in a highly symptomatic 49-year-old woman using a combined endocardial–epicardial approach, which could be taken into consideration as a safe and effective alternative method for treating similar arrhythmias originating from complex sites.

Epicardial ablation of incessant left atrial appendage tachycardia in a case with tachycardiomyopathy

Atrial tachycardias originated at the left atrial appendage (LAA) are uncommon; often they are incessant and might induce tachycardiomyopathy, as discussed by Hillock et al. (Heart Rhythm;3(4):467-469, 2006). A case of a 21-year-old woman with incessant atrial tachycardia is presented, refractory to medical therapy, echocardiography showed global dilation with LV ejection fraction of 20%. After two failed endocardial ablations, an epicardial access was attempted. The earliest activation site was located at the tip of the epicardial aspect of the LAA. RFCA was successful at this site. The patient remains asymptomatic during a follow-up of 10 months; the ventricular function was completely recovered after 6 months (LVEF of 50%).

The characteristics and efficacy of catheter ablation of focal atrial tachycardia arising from an epicardial site

BACKGROUND

Although epicardial structures around the atrium such as adipose tissue possess arrhythmogenicity, little is known about atrial tachycardias (ATs) originating from epicardial sites (Epi-ATs). This study aimed to elucidate the prevalence, characteristics, and outcome after radiofrequency catheter ablation (RFCA) of Epi-ATs and to reveal the association between Epi-ATs and the epicardial structures.

METHODS

The electrocardiographic, electrophysiologic, and anatomical properties and results of RFCA were analyzed in 42 patients with a total of 49 ectopic ATs.

RESULTS

Six Epi-ATs (12%) were observed in six patients (14%). Four of six were respiratory cycle-dependent ATs and one was a swallowing-induced AT. The Epi-AT origins were adjacent to a pulmonary vein (five cases) and vein of Marshall (one case). A Valsalva maneuver or atropine infusion to define the arrhythmia mechanism affected the appearance of the Epi-ATs. The congruity rate between epicardial adipose tissue and the AT origin was significantly higher (100% vs. 44%, p = .045), and the epicardial adipose tissue volume of the atrium was significantly larger (104.1 vs. 64.6 ml, p = .04) in the Epi-AT group. Endocardial RFCA targeting the AT foci resulted in acute success in five of five cases. However, electrical isolation including of the AT foci resulted in acute failures (two of three cases) or a recurrence (one of one case).

CONCLUSIONS

Six Epi-ATs were associated with thoracic veins and epicardial arrhythmogenic structures. The main cause provoking the Epi-ATs was associated with autonomic nerve activity.

Percutaneous epicardial approach for LAA ligation

PURPOSE

The left atrial appendage (LAA) is believed to be a source for thrombus formation and an ancillary structure involved in the initiation and maintenance of atrial fibrillation (AF). LAA ligation has been proposed as adjunctive therapy for the treatment of AF. This study will determine the feasibility of a percutaneous epicardial approach for LAA ligation.

METHODS

The pericardium of 5 dogs was accessed via percutaneous subxyphoid approach. A 20F epicardial cannula was inserted into the pericardial space and contrast-injected to visualize the LAA. Under fluoroscopic guidance, a suction cup catheter was inserted and attached to the LAA. A 12F snare device was inserted over the vacuum cup to ligate the LAA. The closure of the LAA was verified with LA angiography, in the first 2 dogs, and ICE in all 5 animals. All animals were sacrificed for post hoc assessment of LAA closure.

RESULTS

All 5 dogs underwent successful epicardial suture ligation of the LAA. In the first 2 dogs, LA angiography demonstrated complete closure of the LAA. All dogs underwent gross examination of the LAA. Post hoc assessment was notable for a small well-circumscribed hematoma on the LAA, consistent with point of suction cup attachment, as well as complete closure of the entire LAA. No laceration or perforation was noted on the LAA.

CONCLUSIONS

Exclusion of the LAA via a novel percutaneous epicardial-only approach was successful without complications. This demonstrates the feasibility of this technique in an animal model, and may provide an effective approach for epicardial-only LAA exclusion in humans.

Epicardial Ablation of Supraventricular Tachycardias

Supraventricular arrhythmias are the most common cardiac arrhythmias encountered; however, it is uncommon that supraventricular tachycardias require percutaneous epicardial access for successful mapping and ablation. There are particular scenarios where epicardial access and ablation should be considered. Certain accessory pathways particularly in the posteroseptal region may require epicardial access for successful ablation. These pathways may also be approached from within the coronary sinus system. In addition, tachycardias near the phrenic nerve in the right atrium or left atrium may require epicardial access for successful ablation or to allow displacement of the phrenic nerve facilitating safe catheter ablation.

The left atrial appendage in humans: structure, physiology, and pathogenesis

For many years, the left atrial appendage (LAA) was considered a dormant embryological remnant; however, it is a structurally complex and functional organ that contributes to cardiac haemodynamic changes and volume homeostasis through both its contractile properties and neurohormonal peptide secretion. When dysfunctional, the LAA contributes to thrombogenesis and subsequent increased predisposition to cardioembolic events. Consequently, the LAA has gained much attention as a therapeutic target to lower this risk. In addition, attention has focused on the LAA in its role as an electrical trigger for atrial tachycardia and atrial fibrillation with ablation of the LAA to achieve electrical isolation showing promising results in the maintenance of sinus rhythm. This in-depth review explores the structure, physiology and pathophysiology of the LAA, as well as LAA intervention and their sequelae.

Left atrial appendage isolation in atrial fibrillation catheter ablation: A meta-analysis

A significant proportion of patients' experience recurrence of atrial fibrillation (AF) despite pulmonary venous isolation (PVI), especially those with persistent AF. Isolation of the left atrial appendage (LAA) may reduce AF recurrence. The aim of this study was to assess the efficacy of LAA isolation in addition to PVI compared with PVI alone. We conducted a comprehensive search of electronic databases, up to April 21st, 2017, for all studies comparing the effect LAA electrical isolation or ligation in addition to PVI, as opposed to PVI alone, on the recurrence of atrial fibrillation after catheter ablation. We used random-effects meta-analysis models to summarize the studies. One RCT and four observational studies enrolling 781 patients were retained. Four studies assessed the added effect of LAA catheter ablation, and one study evaluated the effect of LAA ligation with the aim of LAA electrical isolation. Four studies exclusively enrolled patients with persistent atrial fibrillation and one study predominantly enrolled patients with persistent atrial fibrillation. Follow-up ranged from 12 to 15 months. The addition of LAA isolation to PVI reduced AF recurrence compared with the latter alone (odds ratio (OR) = 0.19; 95% confidence intervals (CI) = 0.10-0.37; P < 0.00001). Left atrial appendage isolation was also associated with a reduction in AF recurrence after repeat ablation (OR = 0.40; CI = 0.25-0.65; P = 0.0003). The addition of LAA isolation to PVI was associated with a decrease in AF recurrence in patients with persistent AF. Further studies are needed to assess the effect on long-term risk of stroke.

Cardiovascular Therapies Targeting Left Atrial Appendage

Left atrial appendage (LAA) closure has evolved as an effective strategy for stroke prevention in patients with atrial fibrillation who are considered suitable for oral anticoagulation. There is strong evidence based on randomized clinical trials with 1 percutaneous device, as well as a large registry experience with several devices, regarding the safety and efficacy of this strategy. In addition, there is encouraging data regarding the effect of epicardial LAA closure on decreasing arrhythmia burden and improvements in systemic homeostasis by neurohormonal modulation. However, there are several unresolved issues regarding optimal patient selection, device selection, management of periprocedural complications including device-related thrombus, residual leaks, and pericarditis. In this review, we summarize the rationale, evidence, optimal patient selection, and common challenges encountered with mechanical LAA exclusion.

Feasibility of directional percutaneous epicardial ablation with a partially insulated catheter

PURPOSE

To demonstrate the feasibility of directional percutaneous epicardial ablation using a partially insulated catheter.

METHODS

Partially insulated catheter prototypes were tested in 12 (6 canine, 6 porcine) animal studies in two centers. Prototypes had interspersed windows to enable visualization of epicardial structures with ultrasound. Epicardial unipolar ablation and ablation between two electrodes was performed according to protocol (5-60 W power, 0-60 mls/min irrigation, 78 s mean duration).

RESULTS

Of 96 epicardial ablation attempts, unipolar ablation was delivered in 53.1%. Electrogram evidence of ablation, when analyzable, occurred in 75 of 79 (94.9%) therapies. Paired pre/post-ablation pacing threshold (N = 74) showed significant increase in pacing threshold post-ablation (0.9 to 2.6 mA, P < .0001). Arrhythmias occurred in 18 (18.8%) therapies (11 ventricular fibrillation, 7 ventricular tachycardia), mainly in pigs (72.2%). Coronary artery visualization was variably successful. No phrenic nerve injury was noted during or after ablation. Furthermore, there were minimal pericardial changes with ablation.

CONCLUSIONS

Epicardial ablation using a partially insulated catheter to confer epicardial directionality and protect the phrenic nerve seems feasible. Iterations with ultrasound windows may enable real-time epicardial surface visualization thus identifying coronary arteries at ablation sites. Further improvements, however, are necessary.

Left Atrial Appendage Occlusion, Shared Decision-Making, and Comprehensive Atrial Fibrillation Management

The epidemic of atrial fibrillation (AF) requires a comprehensive management strategy that uses the full force of available data and technology, including anticoagulation, ablative therapy, and left atrial appendage occlusion. Patient-centered care with an emphasis on shared decision-making is particularly relevant to the authors' understanding of the complexity of AF and has helped them tailor therapy in this ever-growing patient population.

Left Atrial Appendage characteristics in patients with Persistent Atrial Fibrillation undergoing catheter ablation (LAAPAF Study)

Background

Despite technological and scientific efforts, the recurrence rate of persistent atrial fibrillation (AF) remains high. Several studies have shown that in addition to pulmonary vein (PV) isolation other non-PV triggers, particularly left atrial appendage may be the source of initiation and maintenance of AF. There are few studies showing the role of left atrial appendage (LAA) isolation in order to obtain higher success rate in persistent AF patients.

Objective

We analyzed the LAA volume, volume index and shape relative to the LA in patients with persistent AF undergoing AF ablation.

Methods

Fifty-nine consecutive patients with persistent AF who underwent catheter ablation were enrolled. Computerized tomography (CT) was performed in order to assess left atrial and PV anatomy including the LAA. Digital subtraction software (GE Advantage Workstation 4.3) was used to separate the LAA from the LA and calculate: LA volume (LAV), LA volume index (LAV/body surface area), LAA volume (LAAV), LAA volume index (LAA volume/LA volume), and LAA morphology [chicken wing (CW) or non-chicken wing (NCW)].

Results

The mean age was 64.6 ± 9.8 years, 44 % male, and LA diameter 47.6 ± 7.8 mm. Median follow-up (FU) was 13 months. All patients had antral isolation of PVs and ablation of complex fractionation ± linear ablation (roof line/superior coronary sinus/mitral line). Among 59 patients with persistent AF, 26 (44 %) patients were diagnosed with AF recurrences. Mean LAV was 145.0 ± 45.9 ml, LAVI 68.9 ± 20.0 ml/m², LAAV 10.3 ± 4.0 ml, and LAAVI 7.3 ± 2.7 ml/m². LAA shape was non-chicken wing (NCW) in the majority of patients (51 %). LAA parameters were not significantly different between patients with and without AF recurrence (LAAV 11.0 ± 4.3 ml vs. 9.7 ± 3.8 ml, p=0.26; LAAVI 7.5 ± 3.0 ml/m² vs. 7.2 ± 2.5 ml/m², p=0.71; LAA shape of NCW 50 % vs 52 %, p=0.75, respectively). LAV was significantly correlated with the LAAV (r: o.47, p=0.009). The incidence of NCW LAA was significantly higher in patients with previous stroke/TIA (80 % vs. 20 %, p=0.04).

Conclusion

The LAA anatomical characteristics (volume/volume index and the shape) were comparable in patients with/out AF recurrence post PVI. It remains to be determined if additional LAA isolation will impact outcomes in patients with persistent AF.

Epicardial ablation of tachyarrhythmia in children: Experience at two academic centers

BACKGROUND

Experience with percutaneous epicardial ablation of tachyarrhythmia in pediatrics is limited. This case series addresses the feasibility, safety, and complications of the procedure in children.

METHODS

A total of nine patients underwent 10 epicardial ablation procedures from 2002 to 2013 at two academic centers. Activation mapping was performed in all cases, and electroanatomic map was utilized in nine of the 10 procedures. Patients had undergone one to three failed endocardial catheter ablations in addition to medical management, and all had symptoms, a high-risk accessory pathway (AP), aborted cardiac arrest with Wolff-Parkinson-White syndrome (WPW), or ventricular dysfunction. A standard epicardial approach was used for access in all cases, using a 7- or 8- Fr sheath. Epicardial ablation modality was radiofrequency (RF) in seven, cryoablation (CRYO) in one, and CRYO plus RF in one.

RESULTS

Median age was 14 (range 8-19) years.

INDICATIONS

drug refractory ectopic atrial tachycardia (one), ventricular tachycardia (VT) (five), high-risk AP (two), and aborted cardiac arrest from WPW - (one). Epicardial ablation was not performed in one case despite access due to an inability to maneuver the catheter around a former pericardial scar. VT foci included the right ventricular outflow tract septum, high posterior left ventricle (LV), LV outflow tract, postero-basal LV, and scar from previous rhabdomyoma surgery. WPW foci were in the area of the posterior septum and coronary sinus in all three cases. Overall procedural success was 70% (7/10), with epicardial ablation success in five and endocardial ablation success after epicardial mapping in two. The VT focus was close to the left anterior descending coronary artery in one of the unsuccessful cases in which both RF and CRYO were used. There was one recurrence after a successful epicardial VT ablation, which was managed with a second successful epicardial procedure. There were no other recurrences at more than 1 year of follow-up. Complications were minimal, with one case of inadvertent pleural access requiring no specific therapy. No pericarditis or effusion was seen in any of the patients who underwent epicardial ablation.

CONCLUSION

Epicardial ablation in pediatric patients can be performed with low complications and acceptable success. It can be considered for a spectrum of tachycardia mechanisms after failed endocardial ablation attempts and suspected epicardial foci. Success and recurrence may be related to foci in proximity to the epicardial coronaries, pericardial scar, or a distant location from the closest epicardial location. Repeat procedures may be necessary.

Spectrum of atrial arrhythmias using the ligament of Marshall in patients with atrial fibrillation

BACKGROUND

The role of the ligament of Marshall (LOM) in patients with atrial fibrillation (AF) has not been well defined.

OBJECTIVE

The purpose of this study was to describe the role of the LOM in patients with AF and related arrhythmias.

METHODS

Fifty-six patients (mean age 63 ± 11 years; persistent AF in 48 [86%]; ejection fraction 0.49 ± 0.13; left atrial diameter 4.7 ± 0.6 cm) with LOM-mediated arrhythmias were included.

RESULTS

A LOM-pulmonary vein (PV) connection was present in 18 patients (32%) and was eliminated with radiofrequency (RF) ablation at the left lateral ridge or crux (n = 12), at the mitral annulus (n = 3), or with alcohol/ethanol (EtOH) ablation of the vein of Marshall (VOM; n = 3). A LOM-mediated atrial tachycardia (AT) was present in 13 patients (23%). Thirty-one patients with refractory mitral isthmus conduction were referred for potential EtOH ablation. In the 6 patients in whom VOM was injected during perimitral reentry, EtOH resulted in slowing in 3 patients and termination in 1 patient. In others, EtOH infusion resulted in complete isolation of the left-sided PVs and left atrial appendage. Repeat RF and adjunctive EtOH ablation of the VOM tended to be more effective in creating conduction block across the mitral isthmus than RF ablation alone (P = .057).

CONCLUSION

The LOM is responsible for a variety of arrhythmia mechanisms in patients with AF and atrial tachycardia. It may be ablated at any point along its course, at the mitral annulus, at the lateral ridge/PV antrum, and epicardially in the coronary sinus and the VOM itself. EtOH ablation of the VOM may be an adjunctive strategy in patients with refractory perimitral reentry.

Percutaneous epicardial ablation of incessant atrial tachycardia originating from the left atrial appendage

A 38-year-old woman presented with antiarrhythmic drug-refractory atrial tachycardia (AT). Holter recording demonstrated incessant episodes of AT followed by a long sinus pause. Electrophysiologic study revealed that the earliest endocardial activation was observed at the neck of the left atrial appendage (LAA). After unsuccessful endocardial ablation, epicardial access via a percutaneous subxiphoid approach demonstrated that the earliest epicardial atrial activation was observed on the opposite site to the endocardial LAA neck suggestive of ligament of Marshall (LOM) muscle sleeve as regarding the epicardial sharp potentials under guidance of a circular mapping catheter. Application of radiofrequency (RF) energy at this site terminated the tachycardia. After tachycardia ablation, the sinus pause also resolved.

Left atrial appendage closure is preferred to chronic warfarin therapy: the pro perspective

Atrial fibrillation (AF) is associated with increased rates of death, stroke, heart failure, hospitalization, degraded quality of life, reduced exercise capacity, and left ventricular dysfunction. An oral anticoagulant reduces the risk of stroke; however, it places the patient at risk for bleeding complications. Weighing the stroke and bleeding risks remains the key for optimal treatment. Cardiac interventions that can obviate long-term oral anticoagulation hold great promise for the future care of patients with AF and high stroke risk. The percutaneously deployable Watchman device is a paradigm shift in how clinicians can abate the need for continued oral anticoagulation.

Atrial tachycardias arising from the atrial appendages and aortic sinus of valsalva

Focal atrial tachycardias arising from the atrial appendages and the aortic sinuses of Valsalva are less frequently encountered in clinical practice. This review article describes the clinical presentation, surface P wave morphology, electrophysiologic characteristics and treatment of these arrhythmias. Catheter ablation of these focal tachycardias has a high success rate. It is however important to be aware of specific anatomic considerations in these locations for optimal treatment outcomes with low complication rates.

Epicardial ablation of focal atrial tachycardia arising from left atrial appendage in children

Focal left atrial tachycardia (FLAT) although a common cause of supraventricular tachycardia(SVT) among children, the one's arising from left atrial appendage (LAA) present a unique challenge for successful ablation because of anatomical location. We present two children with FLAT arising from the epicardial LAA, successfully mapped and ablated through percutaneuous epicardial approach.

Thoracoscopic resection of the left atrial appendage after failed focal atrial tachycardia ablation

BACKGROUND

This case series describes 3 patients with the unusual location of focal atrial tachycardia in the left atrial appendage who failed catheter ablation but were successfully treated by left atrial appendage resection by a totally thoracoscopic surgical technique.

METHODS

In all 3 cases, left atrial appendage resection was carried out by video-assisted thoracoscopic surgery using only 3 5- to 10-mm incisions, eliminating the need for median sternotomy or thoracotomy. An endoscopic stapler was used to resect the left atrial appendage at its base, successfully eliminating the source of the patients' focal atrial tachycardia.

RESULTS

The mean operative time was 84 minutes. All 3 patients tolerated the procedure without any complications and were discharged on postoperative day 3. At an average follow-up of 4.5 years, all patients remained asymptomatic and with normal ambulatory rhythm monitoring off all antiarrhythmic medications.

CONCLUSIONS

Surgical resection of the left atrial appendage using a totally thoracoscopic approach is a safe and successful treatment option for patients who have failed endocardial catheter ablation. This novel approach utilizes smaller incisions and shorter operative times than the more invasive surgical techniques previously described in the literature.

The Emerging Role of Epicardial Ablation

Sosa and colleagues first described a percutaneous approach (via the subxiphoid area) to access the pericardial space in 1996. Epicardial mapping and ablation is increasingly used for the treatment of supraventricular and ventricular arrhythmias and represents an adjunctive approach for challenging arrhythmias to improve procedural success rates. Epicardial ablation should be considered not only after the failure of an endocardial ablation but often as a first-line approach. Complications may occur during percutaneous access and epicardial ablation, and these might be reduced or avoided by improved operator skills and experience. New tools to access the epicardial space are being evaluated.

Focal atrial tachycardia originating from the distal portion of the left atrial appendage: characteristics and long-term outcomes of radiofrequency ablation

AIMS

The characteristics and response to ablation therapy of focal atrial tachycardia (AT) originating from the distal portion of left atrial appendage (LAAd) are still not quite clear up to now. The goal of this study is to characterize electrocardiographic and electrophysiological features and radiofrequency ablation (RFA) outcomes in patients with focal AT originating from the LAAd.

METHODS AND RESULTS

Fourteen patients (2.1%) (mean age, 25 ± 10 years; nine women; mean symptom duration, 5 ± 5 years) undergoing RFA of focal AT originating from the LAAd were included out of 668 RFA patients. Activation mapping was performed. P waves were classified as negative, positive, isoelectric, or biphasic. Tachycardia that was incessant in all, demonstrated a characteristic P-wave morphology and endocardial activation pattern: P wave was negative in leads I and aVL, highly positive in the inferior leads, and broad and positive in lead V₁. Radiofrequency ablation was acutely successful in 13 of 14 patients. The endocardial activation time of the successful RFA sites was 47.1 ± 4.3 ms before the onset of P wave. There were no complications in any of the 14 patients and long-term success was achieved in 13 of 13 successful RFA patients during follow-up (5 ± 2 years).

CONCLUSION

The LAAd is an uncommon site of origin for focal AT (2.1% incidence). In this case series, focal ATs originating from the LAAd had typical electrophysiological and electrocardiographic characteristics. Focal ablation yielded high acute success rate with low rate of recurrence during follow-up.

Localized reentry within the left atrial appendage: arrhythmogenic role in patients undergoing ablation of persistent atrial fibrillation

BACKGROUND

Left atrial appendage (LAA) is implicated in maintenance of atrial fibrillation (AF) and atrial tachycardia (AT) associated with persistent AF (PsAF) ablation, although little is known about the incidence and mechanism of LAA AT.

OBJECTIVE

The purpose of this study was to characterize LAA ATs associated with PsAF ablation.

METHODS

In 74 consecutive patients undergoing stepwise PsAF ablation, 142 ATs were encountered during index and repeat procedures. Out of 78 focal-source ATs diagnosed by activation and entrainment mapping, 15 (19%) arose from the base of LAA. Using a 20-pole catheter, high-density maps were constructed (n = 10; age 57 ± 6 years) to characterize the mechanism of LAA-AT. The LAA orifice was divided into the posterior ridge and anterior-superior and inferior segments to characterize the location of AT.

RESULTS

Fifteen patients with LAA AT had symptomatic PsAF for 17 ± 15 months before ablation. LAA AT (cycle length [CL] 283 ± 30 ms) occurred during the index procedure in four and after 9 ± 7 months in 11 patients. We could map 89% ± 8% AT CLs locally with favorable entrainment from within the LAA, which is suggestive of localized reentry with centrifugal atrial activation. ATs were localized to inferior segment (n = 4), anterior-superior segment (n = 5), and posterior ridge (n = 6) with 1:1 conduction to the atria. Ablation targeting long fractionated or mid-diastolic electrogram within the LAA resulted in tachycardia termination. Postablation, selective contrast radiography demonstrated atrial synchronous LAA contraction in all but one patient. At 18 ± 7 months, 13/15 (87%) patients remained in sinus rhythm without antiarrhythmic drugs.

CONCLUSION

LAA is an important source of localized reentrant AT in patients with PsAF at index and repeat ablation procedures. Ablation targeting the site with long fractionated or mid-diastolic LAA electrogram is highly effective in acute and medium-term elimination of the arrhythmia.

Left atrial appendectomy after failed catheter ablation of a focal atrial tachycardia originating in the left atrial appendage

This report describes a case of left atrial appendectomy after a failed endocardial catheter ablation of a continuous drug-refractory left atrial appendage (LAA) tachycardia in a 9-year-old boy. Electrophysiologic study showed atrial tachycardia (AT) originating in the LAA. Numerous radiofrequency applications with an irrigated-tip catheter were ineffective. During surgery, direct pressure on the apex of the LAA by forceps immediately terminated the AT and restored sinus rhythm. After a left atrial appendectomy, the patient remained free of any arrhythmias during a follow-up period of 18 months.

Recognition and Prevention of Complications During Epicardial Ablation

Although the transthoracic epicardial mapping and ablation technique is a relatively safe procedure, complications can and do occur. The possible complications associated with this technique should be well understood before the procedure. If these complications are recognized early and managed appropriately, the outcome is usually excellent. This review describes the details of how to recognize, prevent, and manage the complications that occur during pericardial access, mapping and ablation, and post procedure.

Epicardial Ablation of Supraventricular Tachycardia

Epicardial catheter-based mapping and ablation of a variety of supraventricular tachycardias is feasible, safe, and effective. Supraventricular tachycardia substrates are not uncommonly epicardial, and approaches with percutaneous epicardial instrumentation or via the epicardial venous structures, such as the coronary sinus, are becoming more widely accepted. These techniques are an important treatment option as an alternative to a more invasive surgical approach or to allowing patients to suffer from an ongoing arrhythmia. New technologies and innovative techniques are being developed that hold great potential to improve the efficacy and safety of the epicardial catheter-based approach to these challenging arrhythmias.