Comparison of the retrograde and transseptal methods for ablation of left free wall accessory pathways

Retroflexed catheter course reduces the risk of right free wall accessory pathway recurrence

INTRODUCTION

Accessory atrioventricular pathways (APs) may mediate atrioventricular reciprocating tachycardia and, in some cases, have the potential to conduct atrial tachycardia rapidly, which can be life threatening. While catheter ablation can be curative, ablation of right free wall APs is associated with a high rate of recurrence, likely secondary to reduced catheter stability along the right free wall atrioventricular groove. We sought to identify characteristics associated with a lower rate of recurrence and hypothesized ablation lesions placed on the ventricular side of the atrioventricular groove using a retroflexed catheter approach would decrease rates of recurrence.

METHODS AND RESULTS

Retrospective chart review of patients who underwent catheter ablation of a right free wall AP from January 1, 2008 through June 1, 2021 with >2 months follow up. Cox proportional hazards regression was used to identify relationships between predictor variables and AP recurrence. We identified 95 patients who underwent ablation of 98 right free wall APs. Median age was 13.1 years and median weight at ablation was 52.3 kg. Overall, 23/98 (23%) APs recurred. Use of a retroflexed catheter course approaching the atrioventricular groove from the ventricular aspect was associated with reduced risk of AP recurrence with (univariable hazard ratio of 0.10 [95% confidence interval: 0.01-0.78]), which remained significant in multiple two variable Cox proportional hazards models.

CONCLUSION

Use of a retroflexed catheter course is associated with a reduced likelihood of AP recurrence. This approach results in improved catheter stability and should be considered for ablation of right free wall APs.

Transseptal versus retrograde approach for ablation of left-sided accessory pathways: impact on radiation exposure

Management of left-sided accessory pathways (APs) is based on catheter ablation through an antegrade or retrograde approach. Both are safe and effective but are associated with exposure to x-rays; however, recipients of ablation are generally young. We sought to evaluate the impact of the approach chosen on dose-area product (DAP). A total of 95 patients who underwent radiofrequency ablation of a left-sided AP between January 2011 and January 2020 were included. The primary endpoint was the radiation dose received by the patient. Secondary endpoints were procedural success and complication and recurrence rates. The mean age of the study population was 34.3 ± 16.6 years. The antegrade transseptal approach was used in 63.5% of cases. By multivariate analysis, the antegrade transseptal approach was associated with a 53% reduction in DAP (p< 0.001). The radiation dose received was also significantly associated with body mass index and total fluoroscopy time (p< 0.001). There was no significant difference in other secondary endpoints between approaches. The use of an antegrade transseptal approach is associated with a significant reduction in DAP compared with the retrograde approach, and procedural success and complication and recurrence rates are similar.

Aortic Regurgitation as a Complication of Electrophysiologic Ablation Techniques: A Narrative Review

BACKGROUND

Radiofrequency catheter ablation is a well-established treatment for several cardiac arrhythmias. Arrhythmias originating from the left side of the heart including ventricular and supraventricular tachycardia and ectopy can be successfully ablated through either transseptal or retrograde aortic approach. Although these techniques have a generally low rate of complications, aortic valve injury is a potential complication of ablation at the left cardiac side that warrants more investigation.

OBJECTIVE

The purpose of this review is to evaluate the incidence of iatrogenic aortic valve regurgitation and explore the potential mechanisms and risk factors that might contribute to aortic valve injury during radiofrequency ablation. Additionally, the course and progression of aortic regurgitation in the reported cases will be described.

METHODS

Authors searched PubMed for articles using the keywords "ablation" AND "aortic insufficiency" OR "aortic valve injury" OR "aortic regurgitation". Case reports and series as well as retrospective and prospective studies were included, and relevant review articles and editorial comments were used as a supplementary source of data. A total of 19 references were used and a detailed description of patient characteristics, procedural techniques, and incidence, predictors, and fate of aortic regurgitation were reported by 11 clinical studies.

RESULTS

There is a small risk of significant iatrogenic aortic regurgitation after radiofrequency ablation of left-sided cardiac arrhythmias, especially techniques performed via a retrograde aortic approach.

CONCLUSION

Although the risk is not confined to procedures applying direct energy to the aortic cusp region, a more aggressive ablation applied in the vicinity of the valvular complex seems to be associated with a higher risk. Routine post-procedural surveillance should be adopted to detect de novo aortic valve injury following radiofrequency ablation techniques.

Catheter ablation of complex cardiac arrhythmias: Single-centre experience in Armed Forces

Background

Complex arrhythmia ablation remains a technical challenge despite advances in hardware and mapping techniques. The aim of the study was to analyse the efficacy of radiofrequency ablation of arrhythmias requiring complex electrophysiological procedures at a tertiary-care centre.

Methods

A retrospective study was done for catheter ablation of arrhythmias performed at a single centre from Aug 2012 to Nov 2016 (4 years 4 months). The standard ablation involved conventional catheters with antegrade right heart and retrograde left heart access. The procedure was considered complex, if it involved 3 D electro-anatomical (EA) guidance for mapping or required special hardware and/or trans-septal puncture.

Results

Of 333 electrophysiology (EP) cases 265 qualified for ablation. The cohort of arrhythmias requiring complex procedure (n = 94) comprised of supraventricular 15 (15.9%), atrioventricular 43 (44.7%) and ventricular 36 (38.3%). The procedure used three-dimensional EA mapping in 31; trans-septal puncture for left atrial access in 40; and use of special catheters and sheaths in all 94 procedures. The overall success in the complex group after the first procedure was 87.2% versus 88.3% (P < 0.05), and after redo procedure it was 90.4% vs 94.7% (P < 0.05). There were three complications (pericardial perforation: 2; cardioembolism: 1) only in the complex group. The fluoroscopy time for complex was longer than that of the standard procedure (25.10 ± 6.32 versus 15.23 ± 5.33 min, P = 2.54).

Conclusion

Arrhythmias requiring complex electrophysiological procedure for ablation have a comparable success rate to standard ablation procedure but at the cost of extra hardware, complications and fluoroscopy time.

A safe and simple technique for crossing stenotic aortic valves

OBJECTIVES

To describe and to validate a new technique for crossing stenotic aortic valves (AV).

BACKGROUND

Current techniques for crossing the AV may be time-consuming and hazardous.

METHODS

One hundred consecutive patients with severe aortic stenosis treated by transfemoral TAVI were prospectively selected to have an initial attempt of 5 min to cross the AV with a novel pigtail/J-wire technique before switching to the conventional Amplatz^®/straight wire approach. For the pigtail/J-wire technique, the catheter is placed 3-4 cm above the AV and turned anteriorly in the 30° RAO view. A J-wire pushed out of the pigtail-catheter will reach the anterior wall of the ascending aorta, forming a u-shaped curve above the AV. The height of the pigtail catheter determines the width of the curve, rotation will help to find an orientation, where the vertex of the curved J-wire easily passes the AV. We analyzed the primary success rate within 5 min and the mean crossing time required.

RESULTS

Patients were 83.5 ± 5.5 years of age and predominantly male (62%). Primary success rate was 86%, AV crossing took 48.2 ± 34.6 s without complications. Fourteen failed cases were successfully managed with AL1- (6) and both, AL1- and AL2-catheters (8), respectively CONCLUSIONS: The pigtail/J-wire technique for AV crossing is safe, simple and fast. Primary placement of a pigtail catheter into the left ventricle at a success rate of 86% facilitates TAVI procedures.

Retrograde aortic access during ventricular tachycardia ablation: Indications, techniques, and challenges

The retrograde aortic (RA) route is a widely used access route for mapping and ablation of ventricular tachycardias (VT) arising from the left ventricular endocardium. With the expanding role of VT ablation in patients with significant comorbidity, the choice between the RA and transseptal access routes is an increasingly important consideration. An individualized decision based on the location of the arrhythmogenic substrate, vascular anatomy, aortic valve morphology, and operator experience is necessary when deciding on the optimal access route. Among patients with challenging vascular anatomy, growing experience from structural interventions such as transcatheter aortic valve replacements and peripheral vascular interventions has provided valuable insights into techniques for safe retrograde access. The present review focuses on patient selection for RA access, potential complications associated with the technique, and optimal approaches for access in patients with challenging vascular or aortic valve anatomy.

A subvalvular catheter approach for radiofrequency ablation of right-sided accessory pathways

BACKGROUND

Conventional catheter ablation of right-sided accessory pathways (RAPs) can be challenging.

OBJECTIVE

To determine if a subvalvular catheter approach for RAPs targeting the ventricular insertion site, as on the left side, can improve catheter stability and tissue contact and thus increase acute and chronic ablation success rates.

METHODS AND RESULTS

We retrospectively compared 22 patients (pts) with conventional catheter ablation of RAPs (group 1) with 9 consecutive pts (group 2) undergoing catheter ablation of a RAP using a subvalvular catheter approach targeting the ventricular site of AP. Ablation failed in 2/22 group 1 vs 0/9 group 2 pts (ns) and recurrences of AP conduction were registered in 4/19 group 1 vs 1/9 group 2 pts (ns) during follow-up. Significant shorter values were found in group 2 pts compared with group 1 for number of RF applications (3.6 ± 1.6 vs 8.2 ± 4.3), AP block time (6.2 ± 2.4 vs 9.2 ± 3.9 min), fluoroscopy time (17.2 ± 6.9 vs 25.6 ± 10.3 min), and procedure time (70.8 ± 23.9 vs 138 ± 44.4 min). There were no procedure related complications.

CONCLUSION

Catheter ablation of RAPs using a subvalvular approach seems as effective and safe compared with conventional ablation but with reduced procedure time and radiation exposure and might be at least considered an alternative after failed conventional catheter ablation of RAPs.

Transseptal Puncture for Catheter Ablation in Children

Transseptal puncture (TP) is used in pediatric patients to access the left atrium in left-sided arrhythmia catheter ablation. Performing this procedure can be difficult and risky, especially in small children. In this study, we aimed to evaluate the safety and feasibility of TPs in children ≤ 30 kg. Between April 2012 and April 2018, a retrospective evaluation was conducted of the clinical features, procedural outcomes, and follow-ups of ≤ 30 kg pediatric patients who required TPs for left-sided ablations at a pediatric electrophysiology center in which a three-dimensional mapping system was routinely used. A total of 45 pediatric patients who were ≤ 30 kg, underwent TPs: 10 patients ≤ 20 kg (Group 1) and 35 patients > 20 kg and ≤ 30 kg (Group 2). The TP success rate was 97.8%. The median procedure and fluoroscopy times were 120 min and 5.43 min, respectively. One patient developed self-limited pericardial effusion during the procedure; however, there were no incidences of cardiac tamponade. There was no significant difference between the two groups in terms of the procedure time and fluoroscopy time, and pericardial effusion was only observed in Group 2. TPs are safe and feasible in small children. These procedures can be performed with low complication rates in children weighing ≤ 30 kg.

Transseptal or retrograde approach for transcatheter ablation of left sided accessory pathways: a systematic review and meta-analysis

BACKGROUND

Transcatheter ablation is the most effective treatment for patients with symptomatic or high-risk accessory pathways (AP). At present, no clear recommendations have been issued on the optimal approach for left sided AP ablation. We performed this meta-analysis to compare the safety and efficacy of transaortic retrograde versus transseptal approach for left sided AP ablation.

METHODS AND RESULTS

MEDLINE/PubMed and Cochrane database were searched for pertinent articles from 1990 until 2016. Following inclusion/exclusion criteria application, 29 studies were selected including 2030 patients (1013 retrograde, 1017 transseptal) from 28 observational single Centre studies and one randomized trial. Patients approached by transseptal puncture presented a significantly higher acute success (98% vs. 94%, p = 0.040). The incidence of late recurrences (p = 0.381) and complications (p = 0.301) did not differ among the two groups, but the pattern of complications differed: vascular complications were more frequent with transaortic retrograde approach, while cardiac tamponade was the main transseptal complication. No difference was noted in terms of procedural duration and fluoroscopy time (p = 0.230 and p = 0.980, respectively). Meta-regression analysis showed no relation between year of publication and acute success (p = 0.325) or incidence of complications (p = 0.795); additionally, no direct relation was found between age and acute success (p = 0.256) or complications (p = 0.863).

CONCLUSIONS

Left sided AP transcatheter ablation is effective in around 95% of the cases, with a very limited incidence of complications. Transseptal access provides higher acute success in achieving AP ablation; late recurrences are rare but observed similarly following both approaches. Retrograde approach is affected by a relatively high incidence of vascular complications.

The "hidden" concealed left-sided accessory pathway: An uncommon cause of SVT in young people

BACKGROUND

Concealed left-sided accessory pathways (CLAP) are a cause of supraventricular tachycardia (SVT) in the young. Most are mapped with right ventricular (RV) apical/outflow pacing. Rarely, alternative means of mapping are required. We review our experience from three pediatric electrophysiology (EP) centers with a rare form of "hidden" CLAP.

METHODS

All patients <21 years undergoing EP study from 2008 to 2014 with a "hidden" CLAP (defined as an accessory pathway [AP] for which RV pacing at cycle lengths [CL] stable for mapping did not demonstrate eccentric retrograde conduction) were included.

EXCLUSION CRITERIA

preexcitation. Demographic, procedural, and follow-up data were collected.

RESULTS

A total of 23 patients met the criteria (median age, 14.3 years [range 7-21], weight, 51 kg [31-99]). 21 (96%) had SVT and one AFIB (4%). APs were adenosine sensitive in 7/20 patients (35%) and VA conduction was decremental in six (26%). CLAP conduction was demonstrable with orthodromic reentrant tachycardia in all patients, with RV extrastimulus testing in seven (30%) and with rapid RV pacing (<CL 300) in three (13%). Left ventricular (LV) pacing demonstrated CLAP conduction in 17/17 (100%) patients in whom it was used. All 23 CLAPs were successfully ablated (100%) via transseptal approach with radiofrequency energy. Specific ablation techniques included: 16 (70%) during LV paced rhythm, four (17%) during orthodromic reciprocating tachycardia (ORT; 3/4 ventricular entrained), and three (13%) with brief rapid RV pacing. There were no complications. At 18 months (range 3-96), there was one recurrence (4%).

CONCLUSIONS

Some CLAPs are only demonstrable with LV pacing, entrained ORT, or rapid RV pacing. LV pacing facilitated preferential AP conduction, allowing for mapping while maintaining stable hemodynamics.

Transseptal puncture for radiofrequency catheter ablations of left-sided arrhythmias in a paediatric population

Puncturing the atrial septum is frequently used in adults. In children, the transseptal puncture is less common, technically more demanding, and the rate of complications is not well described. We studied the feasibility and safety of this procedure in a retrospective analysis of 157 consecutive children undergoing transseptal puncture for radiofrequency catheter ablation of left atrial targets in two tertiary-care centres between 2005 and 2013. The median age of the patients at intervention was 12.5 years (1.1-18 years), with median weight of 42 kg (range 9.0-97.0 kg). Pre-excitation was found in 102 procedures, accessory pathway with exclusively retrograde conduction in 41, focal atrial tachycardia in nine, left-sided permanent junctional/reciprocating tachycardia-like accessory pathways in three, and atypical atrioventricular nodal re-entry tachycardia in two. All the procedures were guided by fluoroscopy. Additional imaging by transoesophageal echocardiography was used in three patients. Successful transseptal puncture was possible in 99.4% of the cases, ablation in 97.4%. The median time, including mapping and radiofrequency ablation, was 120 minutes (range 60-450), the median fluoroscopy time 10.8 minutes (range 1.8-75), and the median radiation dose 3 Gy cm2 (range 0.3-35). In total, five patients (3.2%) had a recurrent arrhythmia during the observation period of a median of 40 months (range 1-103). No complications associated with the transseptal puncture were observed. Transseptal puncture is a feasible and safe procedure in children. This access allows successful and efficient radiofrequency ablation of arrhythmia of the left atrium in the vast majority of the patients and might be considered as the first-line approach in this population.

Radiofrequency catheter ablation of left-sided accessory pathways via retrograde aortic approach in children

BACKGROUND

We aimed to analyze the results of retrograde aortic radiofrequency catheter ablation of left-sided accessory pathways in children.

METHODS

Between January 2010 and September 2014, 25 children who underwent left-sided accessory pathway ablation with a retrograde aortic approach were evaluated retrospectively.

RESULTS

The mean age of the patients was 11.09±3.71 years. Seventeen patients were male (68%). The mean procedure and fluoroscopy times were 71.54±21.05 min and 31.42±19.57 min, respectively. Radiofrequency energy was delivered with 41.38±15.32 W at 52.38±5.45 °C. Sixteen patients (64%) presented with manifest preexcitation and, 9 had concealed accessory pathways. The location of accessory pathway was left lateral in 16 patients, posteroseptal in 5, left anterolateral in 2, and left posterolateral and left posterior in the remaining 2. The acute success rate was 96%. The patients were followed for a mean of 16.68±18.01 months. There were 2 recurrences. No major complications were observed in the periprocedural period. One patient had groin hematoma, another one had transient severe headache and vomiting. Trivial mitral regurgitation was noted in a patient, which remained the same throughout follow-up. None of the patients developed new aortic regurgitation, pericardial effusion, or thrombi at the site of ablation.

CONCLUSIONS

The retrograde aortic approach can be safely employed with a high success rate for ablation of left-sided accessory pathways in children.

Feasibility and safety of transseptal puncture procedures for radiofrequency catheter ablation in small children weighing below 30 kg: single-centre experience

AIMS

Transseptal puncture (TSP) has become a common approach in catheter ablation of arrhythmia originating from the left atrium. In paediatric patients, however, TSP can be a challenge due to narrower access vessels and small left atrial size, and the safety of TSP in smaller children is yet to be understood. The purpose of this study was to retrospectively evaluate the feasibility and safety of TSP in children weighing below 30 kg.

METHODS AND RESULTS

Among 655 paediatric patients who underwent catheter ablation of arrhythmia between July 2009 and April 2015, 43 cases having structurally normal hearts, weighing <30 kg and requiring TSP were included in the study. Age, height, body weight, diagnosis, and complications during TSP and catheter ablation were evaluated. The median age, height, and body weight (range) were 7.0 years (0.3-11.1), 116.8 cm (54.0-138.4 cm) and 21.5 kg (4.3-29.6 kg), respectively. Diagnosis included manifest (n = 27; 62.8%) and concealed accessory pathway (n = 14; 32.6%) and atrial tachycardia (n = 2; 4.6%). In 10 cases (23.2%), TSP using radiofrequency energy was performed. None of the patients had major complications. Pericardial effusion was recorded as a minor complication in one patient (2.3%).

CONCLUSION

TSP was feasible, safe, and of low risk of complications in children weighing <30 kg.

Catheter ablation for supraventricular tachycardias: contemporary issues

The treatment of cardiac arrhythmias has evolved significantly over the last 30 years. Understanding of arrhythmia mechanisms has led to pharmacologic therapies, surgical interventions and the widely used percutaneous catheter ablation techniques. The focus of this review is centered on the current catheter ablation therapies available for supraventricular tachycardia. We will discuss current management strategies including challenges when considering catheter ablation therapy for management of supraventricular tachycardias: atrioventricular nodal reentrant tachycardia, atrioventricular reentrant tachycardia utilizing an accessory pathway, atrial tachycardia and atrial flutter. Selected contemporary issues related to supraventricular tachycardia physiology, ablation approaches and ablation outcomes and complications will be discussed. Future goals for electrophysiologists are to continue to improve procedural safety and efficiency, while maintaining the impressive success rates that have been achieved.

Transcatheter trans-septal antegrade closure of muscular ventricular septal defects in young children

BACKGROUND

Surgical or transcatheter closure of muscular ventricular septal defects (mVSDs) in young children may be technically challenging and associated with significant complications.

OBJECTIVE

To assess the feasibility of trans-septal antegrade closure of mVSD in a selected subset of young children.

METHODS

This is a prospective study from a single centre from July 2011 to March 2013. Nine infants and children with single or multiple mVSDs were included in the study. The median age and weight were 6 months (range 4-18 months) and 4.5 kg (range 3.8-6.2 kg), respectively. Trans-femoral trans-septal antegrade technique was used in eight children. One child was excluded from the study because of abnormally tortuous anatomy of both the femoral veins and subsequently underwent VSD device closure by the trans-jugular approach. The follow-up evaluation included chest X-ray, ECG, and echocardiogram at 1 month, 3 months, 6 months, and 1 year.

RESULTS

The defects were closed successfully in all eight patients using Amplatzer mVSD device in 5 and Amplatzer Duct Occluder II in 3. Moderate mitral regurgitation due to entrapment of the anterior mitral leaflet occurred in one patient with a posteriorly located mVSD, necessitating removal of the device, and surgical closure of the mVSD. The small additional residual mVSD in one other patient closed spontaneously during the follow-up.

CONCLUSIONS

Transcatheter trans-septal antegrade closure of mVSD in young children is technically feasible and merits further consideration. Symptomatic relief in multiple mVSD can be achieved after closing larger defects.

Randomized trial of conventional transseptal needle versus radiofrequency energy needle puncture for left atrial access (the TRAVERSE-LA study)

Background

Transseptal puncture is a critical step in achieving left atrial (LA) access for a variety of cardiac procedures. Although the mechanical Brockenbrough needle has historically been used for this procedure, a needle employing radiofrequency (RF) energy has more recently been approved for clinical use. We sought to investigate the comparative effectiveness of an RF versus conventional needle for transseptal LA access.

Methods and Results

In this prospective, single‐blinded, controlled trial, 72 patients were randomized in a 1:1 fashion to an RF versus conventional (BRK‐1) transseptal needle. In an intention‐to‐treat analysis, the primary outcome was time required for transseptal LA access. Secondary outcomes included failure of the assigned needle, visible plastic dilator shavings from needle introduction, and any procedural complication. The median transseptal puncture time was 68% shorter using the RF needle compared with the conventional needle (2.3 minutes [interquartile range {IQR}, 1.7 to 3.8 minutes] versus 7.3 minutes [IQR, 2.7 to 14.1 minutes], P=0.005). Failure to achieve transseptal LA access with the assigned needle was less common using the RF versus conventional needle (0/36 [0%] versus 10/36 [27.8%], P<0.001). Plastic shavings were grossly visible after needle advancement through the dilator and sheath in 0 (0%) RF needle cases and 12 (33.3%) conventional needle cases (P<0.001). There were no differences in procedural complications (1/36 [2.8%] versus 1/36 [2.8%]).

Conclusions

Use of an RF needle resulted in shorter time to transseptal LA access, less failure in achieving transseptal LA access, and fewer visible plastic shavings.

Clinical Trial Registration

URL: http://www.clinicaltrials.gov. Unique identifier: NCT01209260.

ECG criteria for accurate localization of left anterolateral and posterolateral accessory pathways

BACKGround : Left lateral accessory pathway (AP) location along the mitral annulus (MA) can influence ablation strategy, including choice of a transseptal or retrograde aortic approach and the use of deflectable sheaths and/or bidirectional catheters. We aimed to develop electrocardiographic (ECG) criteria to accurately localize a left lateral AP, hypothesizing that the relationship of QRS amplitudes in limb leads II and III could be used to differentiate left anterolateral (LAL) from left posterolateral (LPL) AP locations.

METHODS

The ECGs from patients who underwent ablation of a left-sided AP between 2001 and 2008 were evaluated for the relationship of QRS amplitudes in limb leads II and III. A LAL-AP was defined by successful ablation between 12 and 3 o'clock on the MA, as seen in left anterior oblique (LAO) fluoroscopic projection. A LPL-AP was defined by successful ablation between 3 and 6 o'clock in the LAO projection.

RESULTS

In 249 consecutive patients undergoing AP ablation, 23 met the prespecified inclusion criteria: manifest preexcitation due to single AP, ablated successfully in a LAL or LPL location. The ratio of dominant QRS amplitude in lead II to lead III was ≥ 1 in 10/11 patients with LAL-AP, compared with 3/12 patients with a LPL-AP (P = 0.002). Using these criteria, two blinded reviewers predicted a LAL or LPL location with 87% accuracy and 100% interobserver agreement.

CONCLUSIONS

We report new ECG criteria that can be used to accurately predict the anterior and posterior location of a left lateral AP. Such localization may facilitate procedural planning.

New access for radiofrequency catheter ablation of left-sided atrioventricular accessory pathways: safety and efficacy of the transradial approach

BACKGROUND

The safety and efficacy of the transradial approach for radiofrequency catheter ablation (RFCA) of left-sided atrioventricular accessory pathways (APs) was evaluated in the present study.

METHODS AND RESULTS

Included were 40 consecutive patients with type A Wolff-Parkinson-White (WPW) syndrome who underwent RFCA via the radial artery route, and 30 patients with type A WPW syndrome who underwent RFCA via the transfemoral approach (controls) were retrospectively chosen for control. All 45 APs in the 40 patients were successfully ablated: 35 APs were successfully blocked with 1 ablation attempt, and the other 10 APs were ablated after 2-4 attempts. Compared with the transfemoral approach, the total procedure time for the transradial approach was longer (40 +/- 7.7 vs 32.4 +/- 8.7 min, P<0.05) and the fluoroscopic time was similar (7.2 +/- 2.2 vs 7.9 +/- 3.9 min, P>0.05). There were no vascular complications in the transradial group, but 2 patients in the transfemoral developed local hematoma. There was no recurrence of arrhythmia in either group.

CONCLUSIONS

The transradial approach is a safe and effective access for RFCA of left-sided APs.

Catheter ablation of a left free-wall accessory pathway via the radial artery approach

Catheter ablation of the left free-wall accessory pathways (APs) is normally performed by the retrograde transaortic approach via a femoral artery or the transseptal approach. Here we report a case of an overt left free-wall AP, which was successfully ablated with a retrograde transaortic approach via the radial artery without any vascular complications. The patient has remained free of any symptoms or pre-excitation observed on the ECG during a 10-month post- ablation follow-up.

Magnetic Navigation in Left-Sided AV Reentrant Tachycardias: Preliminary Results of a Retrograde Approach

INTRODUCTION

A novel magnetic navigation system allows remote guidance of floppy radiofrequency (RF) ablation catheters. We evaluated the feasibility of mapping and ablation of left-sided accessory pathways (APs) using the retrograde transaortic approach with this system. This might open the gate to retrograde ablation of left atrial arrhythmias.

METHODS AND RESULTS

Twenty consecutive patients were included. A Helios II was used in five and in 15 a Celsius RMT RF catheter with higher magnetic mass and different flexibility was used. Mapping and ablation were attempted. The learning curve was analyzed. Ablation was acutely successful in 60% of the patients using the Helios II and in 80% using the Celsius RMT. Median procedure time was 158 minutes, with median patient and physician fluoroscopy times of 26 and 4 minutes. In the last 10 patients, procedure times became significantly shorter (median 122 minutes, only Celsius RMT catheters) and standard catheters had to be used only twice. No complications occurred.

CONCLUSIONS

Remote retrograde transaortic RF ablation of left-sided APs is feasible, safe, and reduces the physician's fluoroscopy exposure. There is a very steep initial learning curve, with the success rate increasing from 50% in the first 10 cases to 80% in the last 10 cases. Different catheter configurations may influence the outcome.

Shifting of Puncture Site in the Fossa Ovalis During Radiofrequency Catheter Ablation: Intracardiac Echocardiography-guided Transseptal Left Heart Catheterization

Intracardiac echocardiography (ICE) serves as an adjunct to fluoroscopy for electrophysiological procedures by identifying critical anatomic landmarks and confirming catheter-endocardial contact. In the present study, we investigated the usefulness of ICE for radiofrequency catheter ablation. ICE was utilized to guide transseptal puncture in 19 patients undergoing radiofrequency catheter ablation. The fossa ovalis, which was one critical anatomic landmark, had an average vertical diameter of 18.5 +/- 6.9 mm and an average horizontal diameter of 10.0 +/- 2.4 mm, as measured by ICE and fluoroscopy. Although there was only a small shift of the puncture site in the horizontal direction, the puncture site shifted towards the upper edge of the fossa ovalis for 17 patients (89%). Furthermore, we could verify that the distance between the apex of the tent-shape formed by the pressure of the puncture needle in the fossa ovalis and the left atrial wall opposing it was sufficient to carry out the procedure safely. Confirming the puncture site using ICE is useful in carrying out transseptal left heart catheterization safely.

Transseptal left heart catheterisation guided by intracardiac echocardiography

OBJECTIVE

To develop a novel approach of transseptal puncture guided by intracardiac echocardiography and to assess its efficacy.

METHODS

Transcatheter intracardiac echocardiography with a 9 MHz rotating transducer was performed to guide transseptal puncture in 12 patients (mean age 43.1 years, range 31-68) who underwent radiofrequency catheter ablation of left sided accessory pathways. Initially, the echocardiography and transseptal catheters were placed adjacent to each other in the superior vena cava and were withdrawn to the level of the fossa ovalis.

RESULTS

The successful puncture site was associated with visualisation of the fossa ovalis (12 patients, 100%) and the aorta (12 patients, 100%), tenting of the fossa (six patients, 50%), penetration of the needle visualised by the ultrasound catheter (12 patients, 100 %), and echocardiographic contrast material applied in the left atrium (12 patients, 100%). The characteristic jump of the needle onto the fossa ovalis was observed simultaneously with fluoroscopy and intracardiac ultrasound (12 patients, 100%). All procedures were successful. There were no complications associated with the transseptal procedure.

CONCLUSIONS

Intracardiac echocardiography is feasible to guide transseptal puncture. The optimal puncture site can be assessed by simultaneous detection of the characteristic downward jump of the transseptal needle onto the fossa ovalis by intracardiac ultrasound and fluoroscopy.

Ablation of atrial tachycardia originating from the vicinity of the atrioventricular node: significance of mapping both sides of the interatrial septum

OBJECTIVES

The purpose of the study was to examine the value of right- and left-sided mapping to identify the site of tachycardia origin.

BACKGROUND

Focal atrial tachycardia may originate from the vicinity of the atrioventricular node from either side of the interatrial septum.

METHODS

In 16 patients undergoing radiofrequency catheter ablation of perinodal atrial tachycardia, activation mapping of the right and left side of the interatrial septum was performed.

RESULTS

Atrial tachycardia originated from the right side of the interatrial septum in 10 patients (group A) and from the left side in 6 patients (group B). On the right side, earliest atrial activity preceded the onset of the P-wave by 49 +/- 15 ms in group A and by 38 +/- 8 ms in group B (NS), and it preceded the signal recorded from the right atrial appendage by 59 +/- 19 ms in group A and by 60 +/- 13 ms in group B (NS). On the left side, earliest activity preceded the onset of the P-wave by 27 +/- 16 ms in group A and by 51 +/- 6 ms in group B (<0.01), and it preceded the signal obtained from the right atrial appendage by 38 +/- 19 ms in group A and by 73 +/- 9 ms in group B (<0.01). Atrial tachycardias were successfully eliminated in all patients without impairment of atrioventricular conduction. During follow-up, two patients had a recurrence of tachycardia.

CONCLUSIONS

Mapping of only the right side cannot exclude a left-sided origin. Therefore, mapping of both sides of the interatrial septum is required prior to ablation of focal atrial tachycardia originating from the vicinity of the atrioventricular node.

Intra-atrial reentry tachycardia in pediatric patients

Intra-atrial reentry tachycardia (IART), also known as atrial flutter, is a major problem in pediatric cardiology and adult congenital cardiology. Patients have significant morbidity and even mortality associated with this arrhythmia. The use of antiarrhythmic medications has been disappointing in this population. Ablation techniques are being developed which offer some advantages over the use of medication. These techniques include: sophisticated mapping using entrainment, electro-anatomic and non-contact methods for assessment of the anatomy and the reentrant circuit; radiofrequency ablation methods which allow for the creation of linear and transmural lesions; and new methods for assessment of the effects of ablation which focus on the documentation of the creation of a new line of block. These new techniques provide hope for more effective ablation procedures and the possibility of definitive cure of atrial flutter in many patients in this population.

Catheter ablation for cardiac arrhythmias

The safety and efficacy of catheter ablation for treatment of most types of cardiac arrhythmias are well established. These arrhythmias and arrhythmia substrates include AVNRT, accessory pathways, focal atrial tachycardia, atrial flutter, idiopathic ventricular tachycardia, and bundle-branch re-entry. Catheter ablation is considered as an alternative to pharmacologic therapy in the treatment of these cardiac arrhythmias.

Coronary artery stenosis after radiofrequency catheter ablation of accessory atrioventricular pathways in children with Ebstein's malformation

BACKGROUND

Complications concerning the coronary arteries that are directly related to radiofrequency catheter ablation procedures have not been reported in children. Coronary artery lesions, however, have been demonstrated after the endocardial application of radiofrequency current in young animals.

METHODS AND RESULTS

Two boys with Ebstein's anomaly of the tricuspid valve developed clinically asymptomatic coronary artery stenosis after radiofrequency catheter ablation of right-sided accessory atrioventricular pathways with standard catheter technology.

CONCLUSIONS

The complication of coronary artery stenosis demonstrates a substantial risk after right atrial free wall radiofrequency current application in children. The risk of late coronary alterations should be considered when the use of catheter ablation procedures to young patients is proposed.

Internal transcardiac pericardiocentesis for acute tamponade

If the catheter is still in the pericardium when tamponade is recognized during catheterization or electrophysiologic procedures, it can be used for definitive aspiration and relief of tamponade. This is physiologically beneficial to the patient, and psychologically beneficial to both patient and medical staff.