Catheter Ablation Of Atrial Tachycardia Research Articles

Unique feature of novel activation mapping to identify the successful ablation site of atrial tachycardia

A 49-year-old man was referred to our hospital for catheter ablation of atrial tachycardia (AT; cycle length 360 ms). He previously underwent pulmonary vein isolation and cavotricuspid isthmus ablation for paroxysmal atrial fibrillation (AF). Conventional activation mapping with the high-density Rhythmia mapping system (Boston Scientific, Marlborough, MA) revealed the following features: (1) activation breaking out at the inferior wall below the left inferior pulmonary vein in a centrifugal pattern (Online Supplemental Figure 1) and (2) AF was observed inside the left pulmonary vein (LPV) (Figure 1A, a).

Catheter ablation of atrial tachycardia from the non-caronary valsalva sinus

A case report of atrial tachycardia ablation form the non-coronary Valsalva sinus is presented.

Outcome after tailored catheter ablation of atrial tachycardia using ultra-high-density mapping.

Tailored catheter ablation of atrial tachycardias (ATs) is increasingly recommended as a potentially easy treatment strategy in the era of high-density mapping (HDM). As follow-up data are sparse, we here report outcomes after HDM-guided ablation of ATs in patients with prior catheter ablation or cardiac surgery. In 250 consecutive patients (age 66.5 ± 0.7 years, 58% male) with ATs (98% prior catheter ablation, 13% prior cardiac surgery) an HDM-guided catheter ablation was performed with the support of a 64-electrode mini-basket catheter. A total of 354 ATs (1.4 ± 0.1 ATs per patient; mean cycle length 304 ± 4.3 ms; 64% macroreentry, 27% localized reentry, and 9% focal) with acute termination of 95% were targeted in the index procedure. A similar AT as in the index procedure recurred in five patients (2%) after a median follow-up time of 535 days (interquartile range (IQR) 25th-75th percentile: 217-841). Tailored ablation of reentry ATs with freedom from any arrhythmia was obtained in 53% after a single procedure and in 73% after 1.4 ± 0.4 ablation procedures (range: 1-4). A total of 228 patients (91%) were free from any arrhythmia recurrence after 210 days (IQR: 152-494) when including optimal usual care. Tailored catheter ablation of ATs guided by HDM has a high acute success rate. The recurrence rate of the index AT is low. In patients with extensive atrial scaring further ablation procedures need to be considered to achieve freedom from any arrhythmia.

Catheter ablation of atrial tachycardias after mitral valve surgery: A systematic review and meta-analysis.

Data regarding catheter ablation (CA) of atrial tachycardias (ATs) occurring after mitral valve surgery (MVS) are scarce. The aim of this study was to assess the safety and efficacy of CA of ATs in this surgical population through a systematic review of the literature and meta-analysis. A systematic search on PubMed/MEDLINE, EMBASE, and Web of Science was performed considering patients undergoing CA for ATs occurring after MVS. Periprocedural thromboembolic and hemorrhagic complications were assessed. The acute success and maintenance of sinus rhythm (SR) at a mid (<24 months) and long-term follow-up (FU) after CA were investigated along with the burden of arrhythmic recurrence at FU. Fourteen studies for a total of 227 patients were considered. Three-dimensional (3D) mapping systems were used in all studies. Only two major bleedings were recorded with a pooled estimate of periprocedural major complications of 0%. The acute success after CA was 95% with a clear improvement over time. Although maintenance of SR was 71% at a midterm FU, long-term efficacy was as low as 47% due to an increased burden of atrial fibrillation (AF) recurrence despite multiple procedures/patient. In this meta-analysis, CA of postsurgical ATs after MVS proved safe and effective but with still a significant burden of AF recurrence atmore than 24 months of FU due to a progressive atrial substrate deterioration. The improvement of procedural success over time might suggest a learning curve in optimizing the use of 3D mapping systems.

High density mapping and catheter ablation of atrial tachycardias in adults with congenital heart disease.

We used a new grid-style multi-electrode mapping catheter (Advisor™ HD Grid, Abbott) and investigated its use for high density mapping of atrial tachycardias in adult patients with congenital heart disease. All patients with congenital heart disease who had mapping of atrial tachycardias using the new grid-style catheter between March 2018 and April 2019 were included. A total of 24 adult patients had high density mapping of atrial tachycardias using the grid-style multi-electrode catheter. Mean procedure duration was 207 ± 72min., mean fluoroscopy time was 7.1 ± 7.9min. In patients with right atrial substrates, fluoroscopy time was shorter compared to biatrial or left atrial substrates (0.9 ± 2.2min for right atrial substrates, n = 19 vs. 6.3 ± 8.3min for left atrial substrates, n = 2 and 7.5 ± 4.3min for biatrial substrates, n = 3, p = 0.01). A mean number of 14.814 ± 10.140 endocardial points were collected and 2.319 ± 1244 points were finally used to characterize the tachycardia. Procedural success was achieved in 21/24 (88%) subjects and partial success in 2/24 (8%) patients. Recurrence rate was low (12.5%). In one patient, radiofrequency ablation within the cavotricuspid isthmus resulted in occlusion of a branch of the right coronary artery. No complications related to the use of the mapping catheter itself occurred. High density mapping of AT using the grid-style catheter showed promising results with respect to procedural and midterm outcome and fluoroscopy time. Using the grid-style catheter might offer advantages compared to other multi-electrode catheters used for high density mapping of AT in patients with CHD.

Regional isolation in the right atrium with disruption of intra‐atrial conduction after catheter ablation of atrial tachycardia

Ablation of atrial tachycardia (AT) that occurs after cardiac surgery or prior ablation often requires complex lesion sets. In combination with the pre-existing atrial scar, these lesion sets may result in inadvertent intra-atrial conduction block. This study reports the phenomenon of incidental isolation of right atrial (RA) regions that occurs secondary to AT ablation, which in some cases results in profound bradycardia due to sinus exit block. Intracardiac electrograms were examined in consecutive patients who underwent AT ablation in the RA. Cases of localized isolation of the RA were defined as areas that developed electrical dissociation during ablation. Of 132 patients having ablation in both the RA free wall and the cavotricuspid isthmus (CTI), 10 (7.6%) developed unintentional isolation of the lateral RA. Five of these patients had prior mitral valve surgery, comprising 12.2% of all 41 patients with mitral surgery who underwent ablation in the CTI and the RA free wall. All patients with regional isolation had a pre-existing scar in the lateral wall of the RA. In six patients, isolation of the lateral RA resulted in profound bradycardia due to exit block from the peri-sinus node myocardium. Complex ablation lesions in patients with prior valve surgery, prior ablation, or atrial myopathy may result in unintended localized conduction block in the RA. In some cases, isolation of the lateral RA can result in complete sinus exit block with profound bradycardia requiring pacemaker implantation.

Digitalis therapy is associated with higher comorbidities and poorer prognosis in patients undergoing ablation of atrial arrhythmias: data from the German Ablation Registry.

Digitalis glycosides are employed for rate control of atrial fibrillation. Recent studies suggested potential harmful effects of digitalis monotherapy and combination with antiarrhythmic drugs. The aim of the present study was to assess the prevalence and potential impact of digitalis therapy on outcome in patients undergoing catheter ablation of supraventricular arrhythmias. The German Ablation Registry is a nationwide, prospective registry with a 1-year follow-up investigating 12,566 patients receiving catheter ablations of supraventricular arrhythmias in 52 German centres. The present analysis focussed on pharmacotherapy in 8608 patients undergoing catheter ablation of atrial tachycardia, atrial fibrillation, or atrial flutter. Patients receiving digitalis therapy (n = 417) were older and presented a significantly increased prevalence of comorbidities including coronary artery disease, heart failure, diabetes, and pulmonary disease. One-year mortality was significantly higher in digitalis-treated patients (4.7% vs. 1.3%, p < 0.001), most strikingly in patients undergoing ablation of atrial flutter. This effect was maintained after adjustment for important risk factors. Similar results were obtained for as the combined endpoint of death, myocardial infarction, stroke and major bleeding (6.6% vs. 2.7%, p < 0.001), and non-fatal rehospitalisations (54.1% vs. 45.1%, p = 0.001). In the present study of patients undergoing catheter ablation of supraventricular arrhythmias, an association of digitalis therapy with increased mortality and an increased rate of other severe adverse events were observed. The results from this 'real-life' registry are consistent with previously published studies. However, whether digitalis therapy promotes a poorer prognosis or may just serve as a marker for this aspect cannot be thoroughly interpreted.

Electroanatomic mapping-guided catheter ablation of atrial tachycardia in children with limited/zero fluoroscopy.

Atrial tachycardia (AT) is an uncommon cause of supraventricular tachycardia in children and it is often resistant to medical therapy. Catheter ablation can be curative in children with AT. However, experience of ablation of pediatric AT is still very limited. The aim of this study, which is the largest series from a single center, was to assess the efficacy and safety of ablation of AT using an electroanatomical-mapping system. It was a retrospective review of 39 children with AT who underwent catheter ablation procedure using the EnSite Velocity system (St. Jude Medical, St. Paul, MN, USA) between July 2012 and April 2017. The mean patient age was 13.32±6.82 years. The location of AT was right sided in 25 and left sided in 13, and both sides in one patient. The mean procedure time was 184.23±60.19 min. Fluoroscopy was not used in 25 of 39 patients. The mean fluoroscopy time in the remaining patients was 5.53±5.22 min. Radiofrequency (RF) ablation was used in 22, cryoablation was used in 10, and both RF and cryoablation were used in seven. Acute success was achieved in 34 patients (87.2%). During a mean follow-up of 51.35±12.62 months, AT recurred in five patients. These patients underwent second ablation procedures and four of them were successful. Final success was achieved in 33 out of 39 patients (84.6%). There were no complications except for one patient who had an uneventful pericardial needle injury during transseptal puncture without effusion. Catheter ablation of AT in children can be performed safely and effectively with a limited fluoroscopy using electroanatomical mapping systems.

Catheter Ablation for Atrial Tachycardia in Adults With Congenital Heart Disease: Electrophysiological Predictors of Acute Procedural Success and Post-Procedure Atrial Tachycardia Recurrence.

This study sought to determine the electrophysiological predictors of acute procedural success and of post-ablation recurrence of atrial tachyarrhythmias (ATs) in our adult congenital heart disease (ACHD) population undergoing catheter ablation for treatment of AT. Catheter ablation is frequently performed to treat persistent AT in ACHD. The predictors of post-ablation AT recurrence have not been well studied in the ACHD population. The authors performed a retrospective study of all catheter ablations for treatment of AT performed in ACHD patients between December 1, 2005, and July 20, 2017, at Columbia University Medical Center. Pre-specified clinical and procedural data of interest and the time from ablation to recurrence were determined by chart and procedure report review. A total of 140 patients (mean age: 45 years) underwent catheter ablation for 182 AT. Of the AT, 179 (93%) were intra-atrial macro-re-entrant tachycardia, and 12 (7%) had a focal origin. The presence of a single mechanism was a predictor of acute procedural success that could be achieved in 89% of the patients. At a median of 49.9 months, 62 patients (44%) had recurrent AT. Time to recurrence was significantly shorter (12.5 months) for recurrent AT in 13 of the 20 patients with previous Fontan procedure. By multivariable analysis, acute procedural success was a positive predictor and prior surgical maze procedure was a negative predictor of AT-free survival. Of the 62 patients with recurrent AT, 42 (68%) had a second catheter ablation procedure, and in 22 of these, the AT mechanism was different than previously observed. Catheter ablation for AT in ACHD patients is an effective method of arrhythmia control. More than 1 ATmechanism per patient is common. Acute procedural success is a predictor of freedom from AT recurrence. The majority of patients achieve multiple arrhythmia-free years.

Left atrial scarring and conduction velocity dynamics: Rate dependent conduction slowing predicts sites of localized reentrant atrial tachycardias

BackgroundLow voltage zones (LVZs) are associated with conduction velocity (CV) slowing. Rate-dependent CV slowing may play a role in reentry mechanisms. MethodsPatients undergoing catheter ablation for AT were enrolled. Aim was to assess the relationship between rate-dependent CV slowing and sites of localized reentrant atrial tachycardias (AT). On a bipolar voltage map regions were defined as non-LVZs [≥0.5 mV], LVZs [0.2–0.5 mV] and very-LVZs [<0.2 mV]. Unipolar electrograms were recorded with a 64-pole basket catheter during uninterrupted atrial pacing at four pacing intervals (PIs) during sinus rhythm. CVs were measured between pole pairs along the wavefront path. Sites of rate-dependent CV slowing were defined as exhibiting a reduction in CV between PI = 600 ms and 250 ms of ≥20% more than the mean CV reduction seen between these PIs for that voltage zone. Rate-dependent CV slowing sites were correlated to sites of localized reentrant ATs as confirmed with conventional mapping, entrainment and response to ablation. ResultsEighteen patients were included (63 ± 10 years). Mean CV at 600 ms was 1.53 ± 0.19 m/s in non-LVZs, 1.14 ± 0.15 m/s in LVZs, and 0.73 ± 0.13 m/s in very-LVZs respectively (p < 0.001). Rate-dependent CV slowing sites were predominantly in LVZs [0.2–0.5 mV] (74.4 ± 10.3%; p < 0.001). Localized reentrant ATs were mapped to these sites in 81.8% of cases (sensitivity 81.8%, 95% CI 48.2–97.9% and specificity 83.9%, 95% CI 81.8–86.0%). Macro-reentrant or focal ATs were not mapped to sites of rate-dependent CV slowing. ConclusionsRate-dependent CV slowing sites are predominantly confined to LVZs [0.2–0.5 mV] and the resultant CV heterogeneity may promote reentry mechanisms. These may represent a novel adjunctive target for AT ablation.

Validation of a novel mapping system and utility for mapping complex atrial tachycardias.

This study sought to validate a novel wavefront mapping system utilizing whole-chamber basket catheters (CARTOFINDER, Biosense Webster). The system was validated in terms of (1) mapping atrial-paced beats and (2) mapping complex wavefront patterns in atrial tachycardia (AT). Patients undergoing catheter ablation for AT and persistent AF were included. A 64-pole-basket catheter was used to acquire unipolar signals that were processed by CARTOFINDER mapping system to generate dynamic wavefront propagation maps. The left atrium was paced from four sites to demonstrate focal activation. ATs were mapped with the mechanism confirmed by conventional mapping, entrainment, and response to ablation. Twenty-two patients were included in the study (16 with AT and 6 with AF initially who terminated to AT during ablation). In total, 172 maps were created with the mapping system. It correctly identified atrial-pacing sites in all paced maps. It accurately mapped 9 focal/microreentrant and 18 macroreentrant ATs both in the left and right atrium. A third and fourth observer independently identified the sites of atrial pacing and the AT mechanism from the CARTOFINDER maps, while being blinded to the conventional activation maps. This novel mapping system was effectively validated by mapping focal activation patterns from atrial-paced beats. The system was also effective in mapping complex wavefront patterns in a range of ATs in patients with scarred atria. The system may therefore be of practical use in the mapping and ablation of AT and could have potential for mapping wavefront activations in AF.

Characterization, Mapping and Catheter Ablation of Atrial Tachycardia with Prior Atriotomy

Introduction: The aim of this study was to develop bidirectional block of intra-atrial reentrant tachycardias (IARTs) late after the repair of congenital heart disease (CHD) using pace-map and entrainment mapping.Methods and results: There were 106 patients enrolled in this study. These patients were divided into two groups as giant right atrium (RA) group and non-giant RA group based on their RA volume measured by Carto. All patients have performed activation and entrainment mapping among these patients, 24 (22.6%) of Giant RA group had dual-loop reentry and 82 patients had single loop reentry. 94 patients (88.7%) found out the gaps by pace-map in SR. Linear ablation was successful in 105 patients (99%). During a mean follow-up period of 105 ± 34 months the success rate of IARTs was 66%, there were significantly different in these two groups(P<0.01). Seven (6.6%) patients in Giant RA group undergone redo procedure.Conclusion: Entrainment mapping in tachycardia and pace-map combined with three-dimensional electroanatomic mapping can elaborate the mechanism of complex re-entry circuits and critical isthmuses as targets for ablation. Pace-map in SR may be a good method for seeking the gap of ablation line to be bidirectional block for linear ablation IARTs.

Radiofrequency Catheter Ablation of Atrial Tachycardias in Congenital Heart Disease: Results With Special Reference to Complexity of Underlying Anatomy.

Radiofrequency catheter ablation has become the treatment strategy of choice for atrial tachyarrhythmias in patients with congenital heart disease (CHD). We analyzed results of radiofrequency catheter ablation in a large cohort of patients with CHD with special reference to complexity of underlying anatomy. One hundred and forty-four patients with CHD and atrial tachyarrhythmias undergoing radiofrequency catheter ablation were classified according to complexity of underlying CHD: simple CHD, n=18 (12%); moderate CHD, n=53 (37%); and complex CHD, n=73 (51%). Overall acute success was achieved in 81% of the patients. Acute success was lower for tachycardias involving the left atrium compared with right atrial tachycardias. Complexity of CHD was associated with longer procedure duration. Tachycardia recurrence was observed in 54% of the patients after a total follow-up of 7.4 years. 75% of all recurrences occurred within the first year. Recurrence of tachycardia was more likely in patients with complex surgical atrial anatomy (ie, Fontan palliation or atrial switch procedure). Major complications occurred in 4 patients and were related to vascular access. Acute procedural success of atrial tachycardia ablation in congenital heart patients was not influenced by complexity of CHD. Long-term outcome with regard to tachycardia recurrence was worse in patients with complex surgical atrial anatomy.

Focal atrial tachycardias from the parahisian region: Strategies for mapping and catheter ablation

Focal atrial tachycardias (ATs) from the parahisian region can be successfully ablated from the right atrial septum (RAS), noncoronary cusp (NCC), and right middle septum (RMS). The optimal mapping and ablation strategy for ATs from these sites remains unclear. The purpose of this study was to investigate the electrophysiologic characteristics and optimal ablation sites of parahisian ATs from the RAS, RMS, and NCC. A total of 362 patients with ATs undergoing radiofrequency catheter ablation of ATs were included. A detailed examination including ECG analysis and electrophysiologic study was performed. Overall, 91 patients had a parahisian site of AT origin, and ablation was successful in 86 (94.5%). ATs were successfully eliminated from the RAS in 23, RMS in 19, and NCC in 44. The earliest "A" potential was recorded at the distal His catheter in 69.4% of NCC ATs vs the proximal His catheter in 83.3% of RAS ATs and 86.7% of RMS ATs. Mean timing of the "A" potential of RMS ATs recorded at the His-bundle catheter was -18.25 ± 7.20 ms, which was later than ATs from the RAS (-24.59 ± 8.73 ms) or NCC (-27.08 ± 5.63 ms). For ATs originating from the RAS and RMS, an A/V ratio <1.22 predicted safe and successful ablation (sensitivity 88.4%, specificity 91.7%). For parahisian ATs, activation sequence and timing of the "A" on the His catheter can provide clues for the origin ofATs. When ablating at the RAS and RMS, an A/V ratio >1.22 identified safe and effective ablation sites.

Arrhythmias Following the Mustard and Senning Operations for Dextro-Transposition of the Great Arteries: Clinical Aspects and Catheter Ablation.

The atrial switch operations, the Mustard and Senning procedures, performed for dextro-transposition of the great arteries, have largely been supplanted by the arterial switch operation. As such, affected patients will only exist for approximately 30 more years. The main arrhythmias in these patients include sinoatrial node dysfunction, intraatrial reentry tachycardia, and sudden death. Device therapy for these patients is well-established, and catheter ablation for atrial tachycardias is highly efficacious. The application of meticulous procedural planning, customization of catheter courses, and electrophysiologic principles to this patient group may be extended to all postoperative complex congenital heart patients.

“Window Sliding” analysis combined with high-density and rapid electroanatomical mapping: its efficacy and the outcome of catheter ablation of atrial tachycardia

Atrial tachycardia (AT) is a clinically challenging arrhythmia that can occur based on atrial substrates. Nowadays, a rapid construction of three-dimensional electroanatomical maps, which has an analysis function for complex arrhythmias, named 'Window Sliding' (WS) is available. However, little data has revealed the efficacy of this mapping strategy. The aim of this study was to investigate the efficacy of the WS analysis for AT treatments. All patients underwent electrophysiological studies during ATs and the characteristics of the ATs were analyzed using rapid high-density mapping followed by the WS analysis. RFA was then performed. Fifty-five ATs were identified in 34 patients (63 ± 17 year-old) and in 51 activation maps (cycle length, 322 ± 120 milliseconds) were successfully constructed with 644 ± 433 points per map during 5.3 ± 2.5min. The types of detected ATs were macro-reentries around the mitral (8) and, tricuspid (12) valves, roof-dependent reentry (5), others (13), and focal patterns (13). Of those that underwent RFA, 46 (98%) were treated successfully. Two ATs were abandoned since their critical sites were close to the His bundle and sinoatrial node. During a mean follow-up period of 179 ± 176 days, 7 patients had documented recurrences of AT. This high-density mapping using the WS analysis was useful for creating the entire picture of the ATs in a short time, resulting in favorable RFA outcomes.

Efficacy and Safety of Catheter Ablation of Atrial Tachycardia Through a Direct Approach from Noncoronary Sinus of Valsalva

Noncoronary aortic cusp (NCAC) in the aorta represents a challenging location for catheter ablation of focal atrial tachycardias (ATs) arising near the His-bundle region. The purpose of this study was to provide an updated report on the methods, efficacy, and safety of catheter ablation of ATs originating from NCAC. The study population includes 23 patients (18 women [78%], mean age 65 ± 12years) with highly symptomatic AT. The atrial mapping was performed during tachycardia to define the earliest atrial activation site. Electrophysiological mapping of the right atrium was initially performed, followed by aortic root mapping when earliest activation was recorded in the proximal electrode of the His-bundle catheter. A direct ablation approach from NCAC was used in every patient independently by the local activation time. Ablations were performed using a steerable 4-mm tip nonirrigated catheter in all patients. Radiofrequency energy resulted in the disappearance of arrhythmias in 22 of the 23 patients (95%). In all procedures, there were no complications. During a mean follow-up of 41 ± 25months, no patient presented with a recurrence, except the 1 patient where the ablation was not effective. In conclusion, catheter ablation of para-hisian ATs through a direct approach from NCAC shows to be safe and effective after 1 procedure per patient.

96-17: Atrial tachycardias in patients with long-standing persistent atrial fibrillation undergoing thoracoscopic epicardial RF ablation

Introduction: Surgical epicardial thoracoscopic RF ablation (SETA) was shown to be more effective in terms of clinical results than catheter based procedures in patients with atrial fibrillation (AF). However, neither surgery nor catheter ablation alone can achieve 100% complete and durable transmural lesions. The aim of this study was to determine mechanisms and localization of atrial tachycardias found after epicardial ablation. Methods: Patients with long-standing persistent AF underwent SETA with aim to create circumferential lesions around the ipsilateral pulmonary veins (PVs) using bipolar RF clamps, to complete linear connecting lesions and to ablate ganglionated plexi using linear pen. As a second step, a detailed 3D electroanatomical mapping (EAM) of both atria using CARTO3 system was performed within 6-8 weeks following surgical procedure. All spontaneous or induced atrial tachycardias (ATs) were mapped and ablated. Results: Sixty patients (mean age 62 years, LA diameter 49 ± 6 mm) were studied. Forty-five patients (75%) had sinus rhythm in the beginning of EAM. Six patients (10%) had typical CTI-dependent right atrial flutter; two patients (5.1%) had right atrial (RA) tachycardia, one patient (2.6%) had focal tachycardia arising from the middle CS, three patients (5%) had perimitral left atrial (LA) flutter, and finally, four patients (6.7%) had AF. All spontaneous ATs were successfully mapped and ablated. As a part of protocol, incremental atrial pacing was performed after finalization of all lines and PV isolations at the end of procedure. In 46 patients (76.7%), no sustained AF and/or AT was induced, in three patients (5%), AF lasting > 30 s was induced, but spontaneously terminated. Non self-terminating AF was induced in two patients (3.3%). In the remaining 9 patients (15%), 13 ATs were induced: 6 arising from the RA and 7 arising from the LA. All but 2 ATs were successfully abolished by RF ablation. Mean procedure and fluoroscopic times of the whole procedure reached 132 ± 37 min and 8 ± 2 min, respectively. 84% of patients maintained stable SR off antiarrhythmic therapy at 12-month follow-up. Reasonable arrhythmia control was achieved in 94% of patients. Conclusion: At least one quarter of patients are suffering from spontaneous ATs and/or AF after SETA. Catheter ablation of ATs following surgery is safe and highly effective. Sequential hybrid approach seems to achieve normal SR in vast majority of patients with previously long-standing persistent AF.

Very long-term outcome of catheter ablation of post-incisional atrial tachycardia: Role of incisional and non-incisional scar

BackgroundThe arrhythmogenicity of right atrial (RA) incisional scar after cardiac surgery could result in atrial tachycardia (AT). Radiofrequency catheter ablation is effective in the treatment of such tachycardia. However, data regarding long-term outcomes are limited. Methods and resultsA total of 105 patients with prior RA incision who underwent radiofrequency catheter ablation of AT were included. In the first procedure, electroanatomic mapping (EAM) revealed a total of 139 ATs in 105 patients, including 88 cavotricuspid isthmus dependent atrial flutters (IDAFs), 5 mitral annulus reentrant tachycardias (MARTs), 44 intra-atrial reentrant tachycardias (IARTs) and 2 focal ATs (FATs). AT was successfully eliminated in 101 (96.1%) patients. During a mean follow-up period of 90±36months, recurrent AT was observed in 23 patients and 21 underwent a second ablation. A total of 23 ATs were identified in redo procedures including 4 IDAFs, 2 MARTs, 12 IARTs and 5 FATs. The time to recurrence was significantly different among various AT types. Acute success was achieved in 20 of 23 redo procedures. Taking a total of 21 patients presenting atrial fibrillation during follow-up into account, 85 patients (81.9%) were in sinus rhythm. No complications except for a case of RA compartmentation occurred. ConclusionRA incisional scar played an essential role in promoting both IDAF and IART, while non-incisional scar contributed to a substantial rate of late recurrent AT in forms of both macroreentry and small reentry. Catheter ablation using EAM system resulted in a high success rate during long-term follow-up.

Atrial tachycardia ablation in patients with a functional single ventricle after the Fontan surgery.

Atrial tachyarrhythmias are a leading source of morbidity and mortality after Fontan-type procedures and antiarrhythmic drug therapy is often ineffective in these patients. To evaluate short- and long-term outcomes of radiofrequency current ablation for atrial tachycardia (AT) in patients after the Fontan procedure, and to report clinical, electrophysiological and electroanatomical characteristics of these arrhythmias. We retrospectively analysed data obtained in 8 patients (5 males, 3 females) after the Fontan procedure who underwent ablation for AT between 2002 and 2013. In order to compare the clinical impact of arrhythmia before and after ablation, we used the modified arrhythmia score, ranging from 0 (no arrhythmia activity) to 12 (very severe arrhythmia). In all patients, electroanatomical mapping using the CARTO system was performed, allowing semiquantification of low-voltage (< 0.5 mV) areas and scars. Seven patients had an atriopulmonary connection and 1 patient had an extracardiac conduit. The mean patient age was 9.4 ± 3.1 years at the time of the Fontan procedure and 26.2 ± 4.6 years at the time of the first ablation. A total of 18 ablations were performed with no complications, 1 to 4 (median 2.5) procedures per patient. In patients who had more than 1 ablation, the mean time from the first to the last procedure was 34.8 months (range 1-64 months). In individual patients, 1 to 4 (median 2.5) different ATs were observed, with the mean tachycardia cycle length of 334 ± 95 ms. In 6 patients, low-voltage area (< 0.5 mV) comprised 25-50% of the right atrium, and in two others it comprised 10-25% and < 10% of the right atrium, respectively. Seven procedures were fully successful (ablation of all ATs), 7 were partially successful (ablation of only some AT, including clinical arrhythmia, but not of all ATs) and 4 were unsuccessful (failed ablation of clinical AT). The mean procedural, fluoroscopy and ablation times were 176 ± 54.6, 13.7 ± 5.7 and 21.7 ± 11.9 min, respectively. Freedom from arrhythmia during the mean follow-up of 58.6 ± 46 months (range 11-127 months) since the last procedure was obtained in 4 patients. The median arrhythmia score after the last ablation was significantly reduced compared to baseline (4.5 vs. 8; p < 0.05). Catheter ablation of AT in patients after the Fontan procedure is safe but its acute and long-term efficacy is limited. Due to complex and extensive substrate, along with complex anatomy, recurrences are frequent and patients may require repeat ablation procedures. Suppression of arrhythmia is associated with an improved clinical status of the patients.