Role of radiofrequency ablation in the management of supraventricular arrhythmias: experience in 760 consecutive patients

Combined modified Valsalva maneuver with adenosine supraventricular tachycardia: A comparative study

BACKGROUND AND IMPORTANCE

Paroxysmal supraventricular tachycardia (PSVT) is an arrhythmia commonly seen in the emergency department. Both modified Valsalva maneuver (MVM) and intravenous adenosine are the first line treatment, of which the former has e lower success rate while the latter has a higher success rate but some risks and adverse effects. Given both of these reverse rhythms quickly, combining them may achieve a better effect.

OBJECTIVE

The objective of this study is to evaluate the success rate and potential risk of combining the use of intravenous adenosine while patients were doing MVM as a treatment for paroxysmal supraventricular tachycardia(pSVT).

DESIGN, SETTINGS AND PARTICIPANTS

We recruited patients with pSVT from 2017 to 2022, and randomly assigned them into 3 groups, MVM group, intravenous adenosine group, and combination therapy group, in which MVM was allowed to be performed twice, while intravenous adenosine was given in a titration manner to repeat three times, recorded the success rate and side effects in each group.

MAIN RESULTS

The success rate of the MVM group, adenosine group, and combination group are 42.11%, 75.00 and 86.11%, respectively. The success rate of the adenosine group and combination group is significantly higher than the n MVSM group (p < 0.01, p < 0.001), while the success rate of the combination group is higher than the adenosine group, it has no significant difference (p = 0.340). In terms of safety, the longest RR durations (asystole period) are 1.61 s, 1.60s, and 2.27 s, there is a statistical difference among the three groups (p < 0.01) and between the adenosine and combination group (0.018).

CONCLUSION

Therefore, we can conclude that combination therapy has a relatively high success rate and good safety profile, but the current study failed to show its superiority to adenosine.

Total atrial conduction time as a possible predictor of atrial fibrillation recurrence after catheter ablation for paroxysmal atrial fibrillation: relationship between electrical atrial remodeling and structural atrial remodeling time courses

PURPOSE

Recently, the estimated total atrial conduction time measured using tissue Doppler imaging (PA-TDI duration) has been reported as a more accurate predictor of atrial fibrillation (AF) recurrence after catheter ablation than left atrial volume index (LAVI). The PA-TDI duration is considered to reflect electrical and structural remodeling in the right atrium (RA) and left atrium (LA). We sought to investigate the association between AF recurrence and PA-TDI duration after AF ablation.

METHODS

We studied 209 patients who underwent radiofrequency ablation for paroxysmal AF and 75 patients who underwent second ablation for AF recurrence. We assessed the duration from the onset of the P wave on the surface electrocardiogram to the atrial electrogram in distal coronary sinus (CS) (PA-CSd duration) indicating electrical remodeling of the atrium, the PA-CS proximal duration (PA-CSp duration) representing electrical remodeling of RA, and the conduction time in CS (proximal to distal) (CSp-CSd duration) reflecting electrical remodeling of LA. We also measured LAVI as a marker of structural remodeling of LA.

RESULTS

The PA-TDI duration had a positive correlation with PA-CSd duration. In the patients with AF recurrence, PA-TDI duration, PA-CSd duration, and CSp-CSd duration in the second ablation were significantly longer than those in the first (p < 0.01, respectively), whereas there was no significant difference in LAVI and PA-CSp duration between the first and second ablation sessions.

CONCLUSION

A prolonged PA-TDI duration after AF ablation may indicate advanced electrical remodeling of LA, and may predict AF recurrence after ablation in patients with paroxysmal AF.

Clinical characteristics of challenging catheter ablation procedures in patients with WPW syndrome: A 10 year single-center experience

BACKGROUND

Catheter ablation is the established treatment for patients with symptomatic Wolff-Parkinson-White syndrome (WPW). However, some patients undergo a challenging ablation or have recurrences during the early post-ablation phase. The aim of this study was to evaluate the clinical factors associated with an unsuccessful ablation outcome or repeated sessions.

METHODS

Four hundred seventy-five symptomatic consecutive WPW patients (38.2±16.2 years old, 61% men, 69% with pre-excitation) who underwent an accessory pathway (AP) ablation from August 2005 to December 2015 were enrolled. When APs recurred, a redo ablation procedure was performed according to the patients' desire.

RESULTS

Four hundred thirty-nine patients (92.4%) were cured by ablation, but it failed in 36 (7.6%) after the first procedure. Seventeen patients had AP recurrences during the acute phase within 36h post-ablation. On the other hand, 4 were identified after more than one year. In a multivariate logistic regression analysis, multiple, parahisian, and broad APs were significant independent predictors of recurrences after the 1st procedure, with odds ratios of 14.88 (p<0.001), 10.14 (p<0.001), and 6.88 (p<0.001), respectively. Finally, 468 patients (98.5%) received a successful ablation during a mean follow-up of 8.3±3.0 years. However, after the final procedure no significant predictors were recognized. Out of 508 total procedures, three major (0.6%) complications occurred.

CONCLUSIONS

Symptomatic WPW patients with multiple, parahisian, and broad APs had a significantly higher risk of recurrence. In half of the recurrence patients, AP recurrences were confirmed during the acute phase, but were rarely recorded in the very late phase.

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.

Giant left ventricular pseudoaneurysm: a rare acute complication of radiofrequency catheter ablation for premature ventricular contraction

BACKGROUND

Radiofrequency catheter ablation is approved effective therapy for premature ventricular contraction. However, the rare but serious complication such as pseudoaneurysm should be given more attention. It is life-threatening due to the high risk of rupture. Only few cases have been reported in the literature. We herein report a huge acute left ventricular pseudoaneurysm after catheter ablation therapy.

CASE PRESENTATION

A 69-year-old man underwent radiofrequency catheter ablation for premature ventricular contraction at a local hospital. The patient developed shock the second day after ablation. A chest computed tomography (CT) scan showed pericardial effusion. Pericardiocentesis was performed, and the puncture fluid was a bloody pericardial effusion. The transthoracic echocardiogram revealed an 9- × 4-cm giant pseudoaneurysm with a cystic structure in the left ventricular inferior wall near the mitral annulus along the left atrium. The pseudoaneurysm was connected to the left ventricular cavity through a 8-mm neck, and the lumen was filled with systolic and diastolic blood flow. The patient underwent three-dimensional transesophageal echocardiography. The pseudoaneurysm and the tract was clearly visible. Emergency surgery was performed to resect the pseudoaneurysm. A bovine pericardial patch was placed on the neck of the pseudoaneurysm. Echocardiographic examination confirmed the absence of cardiac lesions after the operation.

CONCLUSIONS

It is rare to see such a large pseudoaneurysm after radiofrequency catheter ablation. Clinicians should be allert to the potential risks to patients in the process of an effective treatment. Echocardiography plays an important role in the prompt diagnosis and prognosis of this disease. Emergency surgery is a better method for treatment of huge pseudoaneurysm.

Treatment of left accessory cardiac pathway conduction disorders using radiofrequency catheter ablation under the guidance of the Ensite NavX 3D mapping system: a retrospective study

To investigate the effectiveness and safety of using the Ensite NavX three-dimensional (3D) mapping system during Radiofrequency catheter ablation (RFCA) of left accessory pathway (AP) disorders. A total of 227 patients having their left AP treated by RFCA, were classified into study group (n = 112) and the control group (n = 115). X-ray irradiation time and exposure doses during the course of the operations were recorded. Time taken to place the mapping catheter along with total duration of operations and procedural complications were compared. The X-ray irradiation time and exposure doses in the course of manipulating the ablation catheters were significantly lower in the study group compared to control (5.1 ± 2.3 min vs. 13.1 ± 3.1 min; P < 0.05 and 5.7 ± 2.6 mGy vs. 17.8 ± 4.3 mGy; P < 0.05, respectively). The total duration of operation was also significantly shorter in the study group compared to control (53.1 ± 18.8 min vs. 62.3 ± 20.6 min; P < 0.05). No procedural complications were reported in both groups. The irradiation time and exposure dose along with total operation duration was significantly reduced when the Ensite NavX mapping system was used during RFCA in comparison with traditional X-ray fluoroscopy method.

Evaluation of the effect of radiofrequency catheter ablation on autonomic function in patients with atrioventricular nodal reentrant tachycardia by head-up tilt table test

Background:

One of the recommended treatments for atrioventricular nodal reentrant tachycardia (AVNRT), is radiofrequency catheter ablation (RFCA). However, RFCA may affect the autonomic system. This study aims to evaluate the effect of RFCA on autonomic system in patients with PSVT by head-up tilt table (HUTT) test.

Materials and Methods:

In a before–after study, 22 patients with PSVT were enrolled. Data were collected with a data collection form that included two parts. Electrocardiogram (ECG), echocardiogram, 24-h Holter monitoring, HUTT test, heart rate variability (HRV) indexes, and symptoms of all patients were recorded 24 h before and 1 month after the ablation. Wilcoxon, McNemar, Mann–Whitney U, and Chi-square tests were used to analyze the data.

Results:

Of the total 22 patients, 31.8% were male and 68.2% were female. There were significant differences in heart palpitation (P < 0.0001) and non-specific symptoms (P = 0.031) and no significant difference in head-up tilt test results and HRV indices before and after RFCA. The results showed that there were no significant differences in specific and non-specific symptoms in patients with AVNRT with positive and negative HUTT before and after RFCA.

Conclusions:

The observed difference in heart palpitation and non-specific symptoms emphasized the role of AVNRT in causing these symptoms. Autonomic dysfunction is more probably an accompanying condition of AVNRT than causing symptoms. We could not find any significance in the results of HUTT after RFCA. HUTT cannot determine or predict the symptoms after RFCA.

Recurrent A V block following ablation for AVNRT

Slow pathway modification has become the mainstay for the treatment of atrio-ventricular nodal re-entrant tachycardia (AVNRT) ablation because of high success rate and low incidence of complications. Our patient had a rare complication of slow pathway modification by radiofrequency ablation (RFA) in form of delayed complete heart block, occurring 10 days after the procedure and resolving in 6 weeks to normal conduction. Complete AV block is a rare immediate complication of RFA but can present weeks later. Transient atrio-ventricular (AV) block during the procedure is seen in all patients who develop delayed AV block and these patients should be monitored closely.

Case report: paravalvular leak as a complication of percutaneous catheter ablation for atrial fibrillation

An increasing number of reports reveal the safety and efficacy of catheter ablation for atrial fibrillation therapy even in patients with a history of prosthetic heart valve. This case report presents a 60 year old female patient who had a prosthetic mitral paravalvular leak as a complication of radiofrequency ablation. Surgery revealed a 15 mm hole and three broken knots in the posterolateral mitral annulus. This report demonstrates radiofrequency ablation for atrial fibrillation in patients with prosthetic mitral valve may cause a paravalvular leak likely as a result of thermal injury. Moreover, patient can be asymptomatic at first. The clinician should keep in mind such complication and the patient should be evaluated in terms of paravalvular leakage.

Radiofrequency ablation of cardiac arrhythmias: past, present and future

The treatment of cardiac arrhythmias has been revolutionized by the ability to definitively treat many patients with radiofrequency catheter ablation, rather than requiring lifelong medication. This review covers the history of how this has developed and the methods used currently and explores what the future holds for this rapidly evolving branch of Cardiology.

Asymptomatic Wolff-Parkinson-White syndrome: incidental ECG diagnosis and a review of literature regarding current treatment

A 19-year-old male presented with periorbital cellulitis responsive to intravenous antibiotics. A routine ECG on admission showed slurred upstroke of the QRS complexes consistent with Wolff-Parkinson-White syndrome (WPW). He has never experienced any cardiac-related symptoms. Once the periorbital cellulitis resolved, he was referred to the specialist cardiology ablation clinic. He was counselled on the arrythmogenic risks of untreated WPW and the potential complications of radiofrequency catheter ablation (RFCA). He decided to go ahead with electrophysiological studies and RFCA, which took place successfully. This case highlights the importance of routine ECG in the diagnosis of asymptomatic WPW. The use of prophylactic ablation of asymptomatic WPW is controversial and should be considered on a case-specific basis.

An in vitro assessment of acoustic radiation force impulse imaging for visualizing cardiac radiofrequency ablation lesions

INTRODUCTION

Lesion placement and transmurality are critical factors in the success of cardiac transcatheter radiofrequency ablation (RFA) treatments for supraventricular arrhythmias. This study investigated the capabilities of catheter transducer based acoustic radiation force impulse (ARFI) ultrasound imaging for quantifying ablation lesion dimensions.

METHODS AND RESULTS

RFA lesions were created in vitro in porcine ventricular myocardium and imaged with an intracardiac ultrasound catheter transducer capable of acquiring spatially registered B-mode and ARFI images. The myocardium was sliced along the imaging plane and photographed. The maximum ARFI-induced displacement images of the lesion were normalized and spatially registered with the photograph by matching the surfaces of the tissue in the B-mode and photographic images. The lesion dimensions determined by a manual segmentation of the photographed lesion based on the visible discoloration of the tissue were compared to automatic segmentations of the ARFI image using 2 different calculated thresholds. ARFI imaging accurately localized and sized the lesions within the myocardium. Differences in the maximum lateral and axial dimensions were statistically below 2 mm and 1 mm, respectively, for the 2 thresholding methods, with mean percent overlap of 68.7 +/- 5.21% and 66.3 +/- 8.4% for the 2 thresholds used.

CONCLUSION

ARFI imaging is capable of visualizing myocardial RFA lesion dimensions to within 2 mm in vitro. Visualizing lesions during transcatheter cardiac ablation procedures could improve the success of the treatment by imaging lesion line discontinuity and potentially reducing the required number of ablation lesions and procedure time.

Meta-analysis of ablation of atrial flutter and supraventricular tachycardia

The purpose of this study was to perform a systematic review and meta-analysis to evaluate the safety and efficacy of radiofrequency ablation (RFA) of typical atrial flutter (AFL) and atrioventricular node-dependent supraventricular tachycardia (SVT) in adult patients. Medline and EMBASE were searched (1990 to 2007) for all study design trials of RFA. Data relating to single- and multiple-procedure success, arrhythmia recurrence, repeat ablation, adverse events, and death were extracted. For RFA in AFL, 18 primary studies with 22 treatment arms and 1,323 patients were identified. Single-procedure success for AFL was 91.7% (95% confidence interval [CI] 88.4% to 94.9%). Multiple-procedure success was 97.0% (95% CI 94.7% to 99.4%). Postablation arrhythmia was noted in 13.2% of patients (95% CI 7.5% to 18.9%), while repeat ablation was reported in 8% (95% CI 4.5% to 11.4%). For RFA of SVT, 39 primary studies with 49 treatment arms in 7,693 patients with accessory pathways and atrioventricular nodal reentrant tachycardia were identified. Single-procedure success for SVT was 93.2% (95% CI 90.8% to 95.5%). Multiple-procedure success was 94.6% (95% CI 92.4% to 96.9). Postablation arrhythmia was noted in 5.6% patients (95% CI 4.1% to 7.2%). Repeat ablation occurred in 6.5% (95% CI 4.7% to 8.3%). For AFL studies, all-cause mortality was 0.6%, and adverse events were reported in 0.5% of patients. For SVT studies, all-cause mortality was 0.1%, and adverse events were reported in 2.9% of patients. In conclusion, studies of RFA for the treatment of patients with AFL and SVT report high efficacy rates and low rates of complications.

Remote magnetic versus manual catheter navigation for ablation of supraventricular tachycardias: a randomized, multicenter trial

INTRODUCTION

The potential benefits of remote robotic navigation for catheter ablation procedures have not been demonstrated in controlled clinical trials. The purpose of this study was to compare remote magnetic catheter navigation to manual navigation for the ablation of common supraventricular arrhythmias.

METHODS AND RESULTS

Patients with supraventricular arrhythmias due to atrioventricular (AV) nodal reentry, accessory pathways, or undergoing AV junctional ablation for complete heart block were randomized in a 3:1 ratio between magnetic (Niobe system and Helios II catheter, Stereotaxis, Inc., St. Louis, MO) and manual navigation for radiofrequency ablation at 13 centers. The primary endpoint of the study was total fluoroscopic time. Fifty-six patients were randomized to magnetic navigation and 15 to manual navigation. AV nodal reentry was the most common arrhythmia in both groups. Total fluoroscopy time was reduced in the magnetic navigation group (median 17.8 minutes, interquartile (IQ) range 9.9,27.8 minutes) compared to manual navigation (27.1, IQ 19.0,48.0, P < 0.05). The acute success rates (91% for magnetic and 87% for manual navigation, P > 0.05) did not differ between groups. The number of lesions delivered was less for magnetic navigation (6, IQ 4,9 vs 10, IQ 7, 26, P < 0.05). Total procedure time (median 151, IQ 111, 221 minutes magnetic and 151, IQ 110, 221 minutes manual) and complication rates (5.4% patients magnetic and 6.7% patients manual) were similar between the groups (both P > 0.05).

CONCLUSIONS

Remote magnetic catheter navigation reduces fluoroscopic time and radiofrequency lesion deliveries for the ablation of common supraventricular arrhythmias compared to manual catheter navigation.

Catheter-induced mechanical trauma to fast and slow pathways during radiofrequency ablation of atrioventricular nodal reentry tachycardia: incidence, predictors, and clinical implications

BACKGROUND

Data on the incidence and significance of catheter-induced trauma to fast and slow pathways are scarce.

OBJECTIVES

To evaluate the incidence, predictors, and clinical implications of inadvertent catheter-induced mechanical trauma to fast and slow pathways during radiofrequency ablation (RFA) of atrioventricular nodal reentry tachycardia (AVNRT).

METHODS

A total of 901 consecutive patients (aged 9-92 years old) with inducible sustained AVNRT underwent RFA of the slow pathway. All procedures were closely monitored for appearance of catheter-induced mechanical block of fast or slow pathways.

RESULTS

Catheter-induced mechanical trauma to fast and/or slow pathways was observed in 121 (13.4%) patients: 86 (71%) patients had trauma of the fast pathway, three (2.4%) had trauma of the slow pathway, and 32 (26.4%) had trauma of both pathways. Mechanical trauma lasted <1 minute in 87 (72%) patients, 1-30 minutes in 23 (19%) and >30 minutes in 11 (9%). A significantly increased procedure discontinuation rate was observed in patients with mechanical trauma as compared to those with no trauma (P < 0.0001). Young patient age (<35) was a strong predictor for the occurrence of mechanical trauma to AV nodal pathways. No significant difference between the trauma and non-trauma groups was found in respect to the number of catheters used during the procedure, the incidence of AV block, and the need for permanent pacemaker implantation.

CONCLUSIONS

Mechanical trauma to fast and slow pathways during ablation of AVNRT is more common than previously recognized, occurring especially in patients aged <35 years.

Ablation of difficult right-sided accessory pathways aided by mapping of tricuspid annular activation using a Halo catheter : Halo-mapping of right sided accessory pathways

OBJECTIVE

To demonstrate that the use of a 20-pole catheter (Halotrade mark) positioned around the tricuspid valve annulus (TVA) is helpful in rapidly localising right free wall accessory pathways (AP), enhancing catheter stability during ablation, and leading to increased success in ablating these challenging pathways.

PATIENTS AND METHODS

Seven consecutive patients who underwent Halo-mapping of right-sided AP were studied. All but one had previously failed ablation. With a Halo catheter deployed at TVA, the accessory pathway location was rapidly identified using the sites of earliest atrial (A) activation during ventricular (V) pacing or orthodromic tachycardia, or earliest V-activation during sinus rhythm or A-pacing were identified. The stability of the ablation catheter was guided fluoroscopically (with reference to the stationary Halo), and electrically (contact artefact between the ablation catheter and Halo poles).

RESULTS

AP locations were identified by the Halo (anterior in one patient, antero-lateral in one, lateral in two, and postero-lateral in three) where similar local VA/AV intervals were recorded at both the ablation catheter and Halo bipoles recording the shortest VA/AV intervals (four of seven patients), contact artefact between the ablation catheter and those Halo bipoles was seen (six of seven patients), or both (three of seven patients). All APs were ablated successfully after a mean RF duration of 5+/-2 min, and 25+/-17 min post Halo deployment without clinical recurrence at 12+/-4 months follow-up.

CONCLUSION

A Halo positioned at the TVA can ease the localisation of right-sided AP, facilitate catheter stability during ablation, and guides successful ablation.

Long R-P' Paroxysmal Supraventricular Tachycardia: What Is the Mechanism?

Deciphering the electrophysiologic mechanism of a long R-P' paroxysmal supraventricular tachycardia typically requires an invasive electrophysiologic study. We present a case where analysis of a simple surface 12-lead ECG was sufficient for the diagnosis.

Utility of nonfluoroscopic three-dimensional electroanatomical mapping in accessory pathways with prior unsuccessful ablation attempts

Three-dimensional electroanatomic mapping was performed to guide radiofrequency catheter ablation in 17 patients with accessory pathways (APs) who had undergone 2.0 +/- 0.9 previous unsuccessful conventional procedures. In 14 patients, activation mapping was directed at the atrial insertion of the bypass during tachycardia (6 patients) or right ventricular pacing (7 patients) or by mapping atrial stimulus-delta-wave intervals. The ventricular insertion of the bypass was mapped and targeted for ablation in the remaining 3 patients. Successful AP ablation was obtained in all but 1 patient (94%) after a mean of 8 +/- 7 radiofrequency pulses, without recurrences during a mean follow-up of 16 +/- 15 months. On the basis of mapping results and successful ablation outcomes, the most likely causes of previous failed ablation attempts were anatomic or mapping reasons (13 patients), catheter manipulation-related problems (2 patients), and miscellaneous reasons (1 patient).

Release of endothelin-1 from human endocardium after radiofrequency catheter ablation and coronary angioplasty: comparative results

BACKGROUND

Plasma levels of endothelin-1 (ET-1) increase after coronary angioplasty (PTCA) due to endothelial injury during the procedure. ET-1 has been found in human endocardial and myocardial cells. It is not known whether ET-1 increases after thermal injury induced by radiofrequency catheter ablation (RFA).

METHODS

We determined plasma ET-1 levels at baseline, immediately after, and at 2 and 6 h post-procedure in 31 patients undergoing PTCA and 16 patients undergoing RFA. Patients subjected to diagnostic coronary angiography (n=15) or electrophysiology study (n=13) served as controls.

RESULTS

Compared to baseline, ET-1 levels increased significantly immediately post-PTCA (55.1+/-20.1 vs. 42.7+/-14.9 pg/ml, p<0.01) and at 2 h post-RFA (98.0+/-11.7 vs. 53.0+/-17.4 pg/ml, p<0.01) and returned to baseline measurements at 2 h post-PTCA and 6 h post-RFA. There was no change of ET-1 levels in the control groups. ET-1 kinetics curve was significantly higher post-RFA compared to post-PTCA (p<0.001). ET-1 immediately post-PTCA correlated with total pressure-time product applied for balloon inflation during the procedure (r=0.56, p<0.01). There was no correlation between ET-1 levels and the number of RFA applications. No patient developed ischemia post-PTCA. There were no complications or arrhythmia recurrences post-RFA.

CONCLUSION

Endocardial thermal injury incurred during RFA is another mechanism of endothelin increase apart from mechanical injury of the coronary endothelium during PTCA and represents further evidence for the existence of the peptide in human endocardial endothelial and myocardial cells. ET-1 increase is delayed and more pronounced post-RFA compared to post-PTCA. Despite that, it does not seem to have any clinical impact in the immediate post-RFA period.

Percutaneous epicardial mapping during ablation of difficult accessory pathways as an alternative to cardiac surgery

OBJECTIVES

The aim of this study was to define the role of percutaneous epicardial mapping for the ablation of previous failed ablation of accessory pathways.

BACKGROUND

Cardiac surgery is the only curative option for failed radiofrequency (RF) catheter ablation of accessory pathway (AP)-mediated tachycardias. We investigated a combined percutaneous epicardial and endocardial approach for failed AP ablations.

METHODS

We present our experience in a series of 6 cases (7 APs) with previous failed attempts at catheter ablation (median 2 attempts, range 1-4) and persistent symptomatic tachycardias. Endocardial mapping of the APs was performed using conventional techniques. Sites with local electrograms suggestive of AP location were selected. When initial endocardial mapping was not successful for ablation of the pathway, percutaneous transthoracic pericardial puncture was performed via a subxiphoid approach, and an ablation catheter was positioned at the epicardial aspect of the putative AP location for epicardial-endocardial electrogram comparison. Endocardial RF energy was applied to locations considered appropriate. Epicardial RF applications were delivered when endocardial applications failed. Coronary arteriography was performed to assess the proximity of coronary arteries to the ablation catheter.

RESULTS

APs were located in the right free wall (4 patients, 5 APs) and the right (1 patient) and left (1 patient) posteroseptal regions. In all patients, epicardial mapping assisted in identifying successful ablation sites. In 3 patients, the earliest atrial activation during orthodromic tachycardia was present in an epicardial electrogram. Successful AP ablation was achieved with an epicardial RF application in 2 patients, either alone or with simultaneous endocardial-epicardial delivery. In the remaining 4 patients, APs were successfully ablated endocardially after epicardial mapping. These patients represent 18% of all cases referred to our institution for ablation of previously failed accessory pathways (6/32 patients).

CONCLUSIONS

A combined endocardial-epicardial approach to mapping and RF ablation can facilitate successful endocardial ablation in most cases. In selected cases, APs can be ablated by epicardial delivery of RF. Epicardial mapping is an effective alternative to cardiac surgery for patients in whom prior attempts at AP ablation have failed.

Acoustic radiation force impulse imaging of myocardial radiofrequency ablation: initial in vivo results

Acoustic radiation force impulse (ARFI) imaging techniques were used to monitor radiofrequency (RF) ablation of ovine cardiac tissue in vivo. Additionally, ARFI M-mode imaging methods were used to interrogate both healthy and ablated regions of myocardial tissue. Although induced cardiac lesions were not visualized well in conventional B-mode images, ARFI images of ablation procedures allowed determination of lesion location, shape, and relative size through time. The ARFI M-mode images were capable of distinguishing differences in behavior through the cardiac cycle between healthy and damaged tissue regions. As conventional sonography is often used to guide ablation catheters, ARFI imaging, which requires no additional equipment, may be a convenient modality for monitoring lesion formation in vivo.

Randomized Study Comparing Combined Pulmonary Vein–Left Atrial Junction Disconnection and Cavotricuspid Isthmus Ablation Versus Pulmonary Vein–Left Atrial Junction Disconnection Alone in Patients Presenting With Typical Atrial Flutter and Atrial Fibrillation

Background— Atrial flutter (AFL) and atrial fibrillation (AF) frequently coexist in the same patient. Recently it has been demonstrated that the triggers for both AF and AFL may originate in the pulmonary veins (PVs). We hypothesized that in patients with both AF and typical AFL, pulmonary vein–left atrial junction (PV-LAJ) disconnection may eliminate both arrhythmias.

Methods and Results— Consecutive patients with documented symptomatic AF and typical AFL were randomly assigned to have PV-LAJ disconnection combined with cavotricuspid isthmus (CTI) ablation (group 1, n=49) or PV-LAJ disconnection alone (group 2, n=59). Within the first 8 weeks after ablation, 32 of the group 2 patients had typical AFL documented, whereas none was seen in group 1. Twenty of these 32 converted to sinus rhythm after initiating antiarrhythmic drugs (AADs). Twelve were cardioverted, and AADs were started. After 8 weeks, all AADS were stopped, and only 3 patients continued to have recurrent sustained typical AFL that was eliminated by CTI ablation. Beyond 8 weeks of follow-up, 7 patients in group 1 and 6 patients in group 2 (14% and 11%, respectively) continued to have AF. Ten of these 13 patients underwent a repeat PV-LAJ disconnection procedure and were cured. The remaining 3 remained in normal sinus rhythm while taking AADs.

Conclusions— In patients with both AFL and AF, PV-LAJ disconnection alone may be sufficient to control both arrhythmias. CTI block reduced early postablation recurrence of arrhythmias, which in the majority of patients reflects a short-term clinical problem.

Multifunctional interventional devices for MRI: a combined electrophysiology/MRI catheter

The design and application of a two-wire electrophysiology (EP) catheter that simultaneously records the intracardiac electrogram and receives the MR signal for active catheter tracking is described. The catheter acts as a long loop receiver, allowing for visualization of the entire catheter length while simultaneously behaving as a traditional two-wire EP catheter, allowing for intracardiac electrogram recording and ablation. The application of the device is demonstrated by simultaneously tracking the catheter and recording the intracardiac electrogram in canine models using 7 and 10 frame/sec real-time imaging sequences. Using solely MR imaging, the entire catheter was visualized and guided from the jugular vein into the cardiac chambers, where the intracardiac electrogram was recorded. By combining several functions in a single, simple structure, the excellent tissue contrast and functional imaging capabilities of MR can be used to improve the efficacy of EP interventions. This catheter will facilitate MR-guided interventions and demonstrates the design of multifunctional interventional devices for use in MRI.

Long-term survival following radiofrequency catheter ablation of atrioventricular junction for atrial fibrillation: clinical and ablation determinants of mortality

BACKGROUND

For patients with drug-refractory atrial fibrillation, radiofrequency catheter ablation of the atrioventricular junction and pacemaker implantation is a nonpharmacologic option routinely used nowadays. Few data are available on the long-term survival following the procedure or on evaluation of the risk factors for death in a large study cohort.

METHODS

The patient population included 359 subjects undergoing atrioventricular junction ablation and pacemaker insertion. Fourteen clinical and 9 ablation variables were collected at baseline. During a mean following-up of 40.8 +/- 25.6 months, 46 patients died. Survival probability was estimated by the Kaplan-Meier methods. Multivariate Cox proportional hazards regression analysis was applied to define predictors of death.

RESULTS

Mean age was 64.6 +/- 10.6 years with 203 male (57.7%). Actuarial survival probability for the total patients was 0.953 and 0.827 at 1 and 5 year. Four clinical variables, but no ablation variables, were found to be independent predictors of death: age > or =65 year (hazard ratio [HR], 1.92; 95% confidence interval [CI], 1.00-3.69), the presence of heart failure (HR, 3.83; 95% CI, 1.87-7.86), coexisting diabetes (HR, 2.91; 95% CI, 1.47-5.77), and the value of fractional shortening < or =20% (HR, 5.79, 95% CI, 3.00-11.18). There were 20 deaths in 28 patients with > or =3 risk factors and 4 deaths in 115 patients with no risk factor.

CONCLUSION

The risk of death in patients undergoing ablation and pacing can be identified by readily available clinical variables. Patients with multiple risk factors are associated with an increasing mortality.

Radiofrequency ablation in pediatric and adult patients: comparative results

BACKGROUND

Radiofrequency (RF) catheter ablation has been widely and successfully employed to cure adult and pediatric patients of a variety of arrhythmias. Only limited data exist which compare the results in these two groups. The aim of this study was to compare the efficacy and safety of RF catheter ablation in pediatric versus adult patients performed by an adult electrophysiology (EP) team.

METHODS

The study group included 327 consecutive pediatric (n=47) and adult (n=280) patients, aged 7-82 years (mean 40+/-19), with symptomatic tachyarrhythmias, who underwent RF ablation during the last 6 years. All but ten patients underwent a full EP study during the same session. Procedures were performed in all but five patients with use of local anesthesia and deep or light sedation. The left heart was approached with use of transaortic (n=36) or transseptal (n=55) or both (n=6) techniques. RF ablation was performed for manifest or concealed accessory pathways in 132 patients, AV nodal slow pathway in 119, atrial tachycardia in 24, atrial flutter in 15, atrial fibrillation in one, ventricular tachycardia in 29, and AV node/His bundle in 7 patients.

RESULTS

RF ablation was successful in 271 (96.8%) patients in the adult group and in all patients (100%) in the pediatric group, with a mean of 15+/-18 (median: 8) vs 12+/-10 (median: 8) RF applications respectively (P=NS). Complications occurred in four patients (1.4%) in the adult group and in one patient (2.1%) in the pediatric group (P=NS). Fluoroscopy time averaged 43+/-40 min vs 39+/-27 min and procedures lasted for 3.0+/-1.9 hours vs 2.8+/-1.4 hours respectively (P=NS). During long-term follow-up of 25+/-19 months, there were 12 (4.4%) recurrences among the adult patients, and three (6.4%) recurrences in children, with nine of them successfully treated with repeat RF ablation. Procedural variables were dependent on the type of arrhythmia ablated, rather than on patient's age. Patients with multiple accessory pathways or atrial flutter required the greatest number of RF applications and the longest fluoroscopy exposure and duration of the procedure; the lowest values of these variables concerned ablation of the slow AV nodal pathway or the AV node/His bundle.

CONCLUSION

RF ablation in adult and pediatric patients performed by an adult EP team is equally efficacious and safe offering cure of symptomatic cardiac tachyarrhythmias in both patient populations.