Catheter Ablation of Peri-AV Nodal Atrial Tachycardia from the Noncoronary Cusp of the Aortic Valve

A novel endocardial activation-derived predictor for focal paraseptal atrial tachycardias: evidence from a multicenter cohort study

BACKGROUND

The electrocardiogram-based algorithm for predicting para-septal atrial tachycardia (PSAT) is limited by the significant overlaps in the P-wave morphology originating from various para-septal sites.

OBJECTIVE

The aim of this study was to investigate the endocardial activation characteristics of PSAT and to seek an endocardial activation-derived predictor for the ablation site.

METHODS

Forty-four patients (11 males, average 62.6±14.7 years) with PSAT ablation in four tertiary medical centers were assigned into three groups according to the ablation site: right atrial (RA) para-Hisian region (Group 1, n=10), the noncoronary cusp (NCC) (Group 2, n=13) and left atrial (LA) para-septal areas (Group 3, n=21). Multiple-chamber activation mapping was performed guided by a 3D navigation system. The discrepancies in the earliest activation time between two of three chambers (ΔRA-LA, ΔRA-NCC and ΔLA-NCC) were calculated in each group and used for pairwise comparisons.

RESULTS

There was significant difference in ΔRA-LA, ΔRA-NCC, and ΔLA-NCC compared among three groups. ΔRA-LA was the only parameter which could consistently predict the ablation site of PSAT with good accuracy (AUC 1.000, sensitivity 100%/ specificity 100%, and cut-off value 7ms for predicting right para-Hisian or NCC ablation; AUC 0.974, sensitivity 92.3%/specificity 95.2%, and cut-off value -4 ms for predicting NCC or left para-septal ablation). Based on two cut-off values, A two-step algorithm was developed to predict the ablation site of PSAT with positive predictive value of 95.4% and negative predictive value of 97.0%.

CONCLUSIONS

ΔRA-LA is a useful endocardial activation-derived parameter for predicting the successful ablation site of PSAT.

Discrimination of atypical atrioventricular nodal reentrant tachycardia from atrial tachycardia by the V-A-A-V response

INTRODUCTION

The electrophysiological discrimination between fast-slow (F/S-) atrioventricular (AV) nodal reentrant tachycardia (NRT) and atrial tachycardia (AT) originating from the interatrial septum remains challenging. While a V-A-A-V response may occur immediately after ventricular induction or entrainment of either tachycardia, the electrophysiological dissimilarities in that response between the two tachycardias remain unclear. The purpose of this study was to identify a diagnostic indicator discriminating F/S-AVNRT from AT by examining the difference in the V-A-A-V response between the two tachycardias.

METHODS

This retrospective study included 17 patients with F/S-AVNRT [7 with common-form F/S-AVNRT using a typical slow pathway (SP) and 10 with superior type F/S-AVNRT using a superior SP] and 10 patients with reentrant AT. All 27 patients presented with long RP supraventricular tachycardia and an initial V-A-A-V response upon ventricular induction or entrainment. The V-A-A-V response in patients with F/S-AVNRT was due to dual atrial responses. We measured the interval between the first (A1) and second atrial electrogram (A2) of V-A-A-V and calculated ΔAA by subtracting A1-A2 from the tachycardia cycle length.

RESULTS

V-A-A-V responses were observed most often upon ventricular induction of F/S-AVNRT (6±5 times) as well as AT (6±6 times; P = 0.87). The V-A-A-V response upon ventricular entrainment was observed in a single patient with F/S-AVNRT versus 10 all patients with AT (P<0.001). ΔAA ranged between -80 and 228 ms in F/S-AVNRT and between -184 and 26 ms in AT. A ΔAA >26 ms predicted a diagnosis of F/S-AVNRT with a 76% sensitivity and 100% specificity, while a ΔAA ←80 ms predicted a diagnosis of AT with a 50% sensitivity and 100% specificity.

CONCLUSIONS

ΔAA is a useful, confirmatory, diagnostic indicator of F/S-AVNRT versus AT associated with the V-A-A-V response. This article is protected by copyright. All rights reserved.

Combined aortic and mitral valvular surgery with the Intuity rapid deployment prosthesis in the aortic position: Operative tips and tricks

The Edwards Intuity valve is a rapid deployment prosthesis designed for the aortic position. There is a paucity of literature on the use of the Intuity valve in combined aortic and mitral double valvular surgery. We present a case that highlights our novel surgical technique for implanting the Intuity valve in the aortic position following insertion of a conventional sutured bioprosthetic valve in the mitral position.

Efficacy of Catheter Ablation From the Non-Coronary Aortic Cusp of Verapamil-Sensitive Atrial Tachycardia Arising Near the Atrioventricular Node

BACKGROUND

Efficacy of catheter ablation from the non-coronary aortic cusp (NCC) of verapamil-sensitive atrial tachycardia arising near the atrioventricular node (AVN-AT) has yet to be fully clarified.

OBJECTIVE

We elucidated the determinant of an effective AVN-AT ablation from the NCC.

METHODS

After identifying the earliest atrial activation site (EAAS) during tachycardia, the direction of the slow conduction zone (SCZ) of reentry circuit was identified by demonstrating manifest entrainment in 26 AVN-AT patients. Catheter ablation was initially performed from the NCC irrespective of the local activation time. If the NCC ablation was ineffective, catheter ablation was performed targeting the SCZ entrance. Then the anatomical relationship between the SCZ and successful ablation site was elucidated.

RESULTS

NCC catheter ablation terminated AVN-AT in 14 patients (NCC Group) but not in 12 (Non-NCC Group). Catheter ablation targeting the SCZ entrance terminated all Non-NCC Group ATs. The local activation time at the NCC relative to the EAAS did not differ between the NCC and Non-NCC Groups (10.1±6.5 vs. 11.2±4.8 msec, p=0.6333). The direction of the SCZ was posterior to the EAAS in all NCC Group patients, however, it was postero-lateral (n=5) and lateral to the EAAS (n=7) in the Non-NCC Group, suggesting that the SCZ existed in the direction of the NCC in NCC Group but was away from the NCC in Non-NCC Group.

CONCLUSION

A close proximity between the NCC and SCZ of the reentry circuit, but not the local activation time at the NCC, determined the efficacy of NCC catheter ablation in AVN-ATs.

Interatrial septal tachycardias following atrial fibrillation ablation or cardiac surgery: Electrophysiological features and ablation outcomes

BACKGROUND

Interatrial septal tachycardias (IAS-ATs) following atrial fibrillation (AF) ablation or cardiac surgery are rare, and their management is challenging.

OBJECTIVE

The purpose of this study was to investigate the electrophysiological features and outcomes associated with catheter ablation of IAS-AT.

METHODS

We screened 338 patients undergoing catheter ablation of ATs following AF ablation or cardiac surgery. Diagnosis of IAS-AT was based on activation mapping and analysis of response to atrial overdrive pacing.

RESULTS

Twenty-nine patients (9%) had IAS-AT (cycle length [CL] 311 ± 104 ms); 16 (55%) had prior AF ablation procedures (median 3; range 1-5), 3 (10%) had prior surgical maze, and 12 (41%) had prior cardiac surgery (including atrial septal defect surgical repair in 5 and left atrial myxoma resection in 1). IAS substrate abnormalities were documented in all patients. Activation mapping always demonstrated a diffuse early IAS breakout with centrifugal biatrial activation, and atrial overdrive pacing showed a good postpacing interval (equal or within 25 ms of the AT CL) only at 1 or 2 anatomically opposite IAS sites in all cases. Ablation was acutely successful in 27 patients (93%) (from only the right IAS in 2, only the left IAS in 9, both IAS sides with sequential ablation in 13, and both IAS sides with bipolar ablation in 3). After median follow-up of 15 (6-52) months, 17 patients (59%) remained free from recurrent arrhythmias.

CONCLUSION

IAS-ATs are rare and typically occur in patients with evidence of IAS substrate abnormalities and prior cardiac surgery. Catheter ablation can be challenging and may require sequential unipolar ablation or bipolar ablation.

Aortic Valve Calcification as a Predictor of Post-Transcatheter Aortic Valve Replacement Pacemaker Dependence

Background

Atrioventricular block requiring permanent pacemaker (PPM) implantation is a common complication of transcatheter aortic valve replacement (TAVR). The mechanism of atrioventricular (AV) block during TAVR is not fully understood, but it may be due to the mechanical stress of TAVR deployment, resulting in possible injury to the nearby compact AV node. Aortic valve calcification (AVC) may worsen this condition and has been associated with an increased risk for post-TAVR PPM implantation. We performed a retrospective analysis to determine if AVC is predictive for long-term right ventricular (RV) pacing in post-TAVR pacemaker patients at 30 days.

Methods

A total of 262 consecutive patients who underwent TAVR with a balloon-expandable valve were analyzed. AVC data were derived from contrast-enhanced computed tomography and characterized by leaflet sector and region.

Results

A total of 25 patients (11.1%) required post-TAVR PPM implantation. Seventeen patients did not require RV pacing at 30 days. Nine of these 17 patients had no RV pacing requirement within 10 days. The presence of intra-procedural heart block (P = 0.004) was the only significant difference between patients who did not require PPM and those who required PPM but they were not RV pacing-dependent at 30 days. Non-coronary cusp (NCC) calcium volume was significantly higher in patients who were pacemaker-dependent at 30 days (P = 0.01) and a calcium volume of > 239.2 mm³ in the NCC was strongly predictive of pacemaker dependence at 30 days (area under the curve (AUC) = 0.813). Pre-existing right bundle branch block (RBBB) (odds ratio (OR) 105.4, P = 0.004), bifascicular block (OR 12.5, P = 0.02), QRS duration (OR 70.43, P = 0.007) and intra-procedural complete heart block (OR 12.83, P = 0.03) were also predictive of pacemaker dependence at 30 days.

Conclusions

In patients who required PPM after TAVR, quantification of AVC by non-coronary leaflet calcium volume was found to be a novel predictor for RV pacing dependence at 30 days. The association of NCC calcification and PPM dependence may be related to the proximity of the conduction bundle to the non-coronary leaflet. Further studies are necessary to improve risk prediction for long-term RV pacing requirements following TAVR.

Embryology of the Cardiac Conduction System Relevant to Arrhythmias

Embryogenesis of the heart involves the complex cellular differentiation of slow-conducting primary myocardium into the rapidly conducting chamber myocardium of the adult. However, small areas of relatively undifferentiated cells remain to form components of the adult cardiac conduction system (CCS) and nodal tissues. Further investigation has revealed additional areas of nodal-like tissues outside of the established CCS. The embryologic origins of these areas are similar to those of the adult CCS. Under pathologic conditions, these areas can give rise to important clinical arrhythmias. Here, we review the embryologic basis for these proarrhythmic structures within the heart.

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

BACKGROUND

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.

OBJECTIVE

The purpose of this study was to investigate the electrophysiologic characteristics and optimal ablation sites of parahisian ATs from the RAS, RMS, and NCC.

METHODS

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.

RESULTS

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%).

CONCLUSION

For parahisian ATs, activation sequence and timing of the "A" on the His catheter can provide clues for the origin of ATs. When ablating at the RAS and RMS, an A/V ratio >1.22 identified safe and effective ablation sites.

Comparison of strategies for catheter ablation of focal atrial tachycardia originating near the His bundle region

BACKGROUND

Recent studies have suggested that para-Hisian atrial tachycardia (AT) can be successfully ablated from the right atrium (RA), left atrium (LA), or noncoronary cusp (NCC) in the aorta; however, the best approach remains unclear.

OBJECTIVE

This study aimed to compare different approaches to radiofrequency catheter ablation (RFCA) of para-Hisian AT.

METHODS

We retrospectively analyzed 68 consecutive patients (49[72%] women; mean age 61 ± 13 years) treated with RFCA for this type of AT. Mapping of the RA (n = 68), LA (n = 21), and NCC (n = 52) was performed during AT to identify the earliest activation site and to apply RFCA.

RESULTS

RFCA successfully terminated AT in the RA in 13 of 28 patients (46.4%), in the LA in 4 of 16 patients (25.0%), and in the NCC in 46 of 52 patients (88.5%) after 1 procedure (P < .05). Atrioventricular block occurred only during RFCA in the RA in 4 of 28 patients (14.3%). After a mean follow-up of 33.5 ± 25.4 months, AT recurrence was observed in 5 of 13 patients (38.5%) ablated in the RA, 1 of 4 (25.0%) ablated in the LA, and 2 of 46 (4.4%) ablated in the NCC (P < .05). RFCA in the LA was effective only if the local activation time (LAT) was earlier than that in the RA. RFCA in the NCC was successful regardless of the LAT (P < .05).

CONCLUSION

Mapping and ablation in the NCC should be always considered in cases of AT originating from the His bundle region, regardless of the LAT.

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 ± 12 years) 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 ± 25 months, 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.

Should the Aortic Root Be the Preferred Route for Ablation of Focal Atrial Tachycardia Around the AV Node?: Support From Intracardiac Echocardiography

OBJECTIVES

The purpose of this study was to determine the optimal approach to focal atrial tachycardia originating from around the atrioventricular node.

BACKGROUND

Focal atrial tachycardia (FAT) demonstrating earliest activation around the atrioventricular (AV) node during right atrial (RA) mapping has been eliminated by ablation at the RA para-Hisian region, from the left atrium (LA) or the noncoronary aortic cusp (NCC). However the optimal approach has not been determined.

METHODS

We conducted a retrospective analysis of a consecutive series of 148 patients undergoing catheter ablation for FAT between 2006 and 2014 in our institution.

RESULTS

Earliest activation was recorded in the peri-AV nodal region during RA mapping in 34 patients (23%). Of these, 7 patients (20.5%) had successful ablation at the RA septum, using either radiofrequency (n = 4) or cryoenergy (n = 3). Seven FATs (20.5%) were ablated from the LA at the region of the aortomitral continuity, and 20 patients (59%) had successful ablation in the NCC, including 1 patient with a recurrence after a temporarily successful cryoablation from the RA. The proportion of the 3 approaches in this series showed a significant temporal evolution and overall frequency favoring ablation in the NCC (p = 0.011 for time trend and 0.013 for actual vs. expected frequencies). Intracardiac echocardiography proved superior catheter stability with the NCC approach. There were 2 cases of atrioventricular block and 1 recurrence after RA ablation versus no complications or recurrent FAT with NCC and LA approaches.

CONCLUSIONS

Most peri-AV nodal FATs can be safely and effectively ablated from the NCC. The strategy of preferential NCC approach avoids RA para-Hisian ablation with the accompanying risk of AV block.

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

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

Mapping strategies in focal atrial tachycardias demonstrating early septal activation: distinguishing left from right

Determining the chamber of origin of focal atrial tachycardias (FATs) arising at or close to the septum might require biatrial mapping. This review focuses on the available tools and methods used to distinguish right atrial from left atrial origin before left atrial access is obtained. These include analysis of P wave morphology, assessing the timing of right atrial septal activation, the sequence of right atrial and/or biatrial activation and analysis of earliest electrogram morphology. The electroanatomical properties of the interatrial septum and coronary sinus that provide the basis for the above mentioned tools have also been briefly described.

Focal atrial tachycardia surrounding the anterior septum: strategy for mapping and catheter ablation

Background—

Focal atrial tachycardias (ATs) surrounding the anterior atrial septum (AAS) have been successfully ablated from the right atrial septum (RAS), the aortic cusps, and the aortic mitral junction. However, the strategy for mapping and ablation of AAS-ATs has not been well defined.

Methods and Results—

Of 227 consecutive patients with AT, 47 (20.7%; mean age, 56.3±11.6 years) with AAS-ATs were studied; among them, initial ablation was successful at RAS in only 5 of 14 patients and at noncoronary cusp (NCC) in 28 of 33 patients. In 45 of the 47 patients, the 46 of 48 AAS-ATs were eliminated at RAS in 8 patients, NCC in 35 patients (earliest activation time at NCC was later than that at RAS by 5–10 ms in 6 patients), and aortic mitral junction in 3 patients (all with negative P wave in lead aVL and positive P wave in the inferior leads), including 1 patient whose 2 ATs were eliminated separately from the NCC and the aortic mitral junction.

Conclusions—

Most of the ATs surrounding the AAS can be eliminated from within the NCC, which is usually the preferential ablation site. Ablation at the RAS and aortic mitral junction should be considered when supported by P-wave morphologies on surface ECG and results of activation mapping and ablation.

Atrial tachycardia originating from the aortomitral junction

Atrial tachycardia (AT) originating from the aortomitral junction is a very rare and challenging disease. Its arrhythmic characteristics have not been described in detail compared with the descriptions of the arrhythmic characteristics of AT originating from the other locations. Only a few case reports have documented successful ablation of this type of AT using transaortic or transseptal approaches. We describe a case with AT that was resistant to right-sided ablation near the His bundle failed and transaortic ablation at the aortomitral junction successfully eliminated.

The role of noncoronary cusp ablation approach in the treatment of perinodal atrial tachycardias

BACKGROUND

Ablation in the noncoronary aortic cusp (NCC) potentially has a role in the treatment of perinodal atrial tachycardias (ATs). The objective of the study was to characterize clinical and electrophysiological properties of perinodal ATs between two groups of requiring and not requiring NCC ablation.

METHODS

A total of 113 patients with focal ATs who underwent electrophysiologic study and radiofrequency catheter ablation were enrolled in the study. The clinical and electrophysiological characteristics of ATs that need and not need NCC ablation were compared.

RESULTS

Totally 20 cases were revealed to have the focal ATs located in the perinodal area. Among them, only five cases (25%) warrant ablation in the NCC, whereas the remainder could be successfully eliminated by ablation from the endocardial right atrium at the perinodal region. There were no clinical and electrophysiological clues observed to have the potential to predict the true original site, including the activation mode, the three-dimensional mapping characteristics of earliest activation site in the right atrium, as well as the time of termination during the ablation in the perinodal area.

CONCLUSIONS

Approximately, one-fourth of the perinodal ATs warrant ablation in the NCC. However, no clinical and electrophysiological clues could predict the potential site of the perinodal ATs.

Prevalence, risk, and benefits of radiofrequency catheter ablation at the aortic cusp for the treatment of mid- to anteroseptal supra-ventricular tachyarrhythmias

BACKGROUND

Some outflow tract ventricular tachycardias (VTs) are known to be successfully ablated from the aortic cusp (AC). However, radiofrequency catheter ablation (RFCA) at the AC for the treatment of supraventricular tachyarrhythmia (SVT) has limited experience.

METHODS

We performed RFCA at the AC in 19 patients (male 64.7%, 46.9 ± 21.9 years old) with mid- to anteroseptal SVTs (12 atrial tachycardias [AT], 7 atrioventricular reciprocating tachycardia [AVRT]), and analyzed the prevalence, electrophysiologic findings, clinical outcome, and compilation risk.

RESULTS

1. Among 113 patients with AT, 13 patients had mid- to anteroseptal AT and 12 patients (8.8%, 53.4 ± 19.8 years old, 58.3% female) underwent successful ablation from the non-coronary cusp (NCC; n=10), right CC (RCC; n=1) or left CC (LCC; n=1) without complication (3.1 ± 2.3 times RF delivery, 6.15 ± 3.08 s for termination). During 19.7 ± 9.8 months of follow-up, AT recurred in a patient with multiple foci. 2. Among 580 patients with AVRT, 27 patients had a mid- to anteroseptal bypass tract (4.7%), and 7 of them (1.1%, 2 pre-excitation syndrome, 5 concealed bypass tract) were successfully ablated at the NCC (n=2) or RCC (n=5) (7.0 ± 7.1 times RF delivery, 9.1 ± 4.4s for termination). Among 5 patients with AVRT successfully ablated at the RCC, one patient developed complete heart block 48 h after procedure, and 2 patients recurred AVRT or delta-wave in ECG during 13.9 ± 11.7 month follow-up.

CONCLUSION

Catheter ablation within the AC is an effective procedure to eliminate mid- to anteroseptal SVTs. However, RFCA on RCC requires a caution for heart block in our limited experience.

Electrocardiographic, electrophysiologic, and anatomical features of ventricular tachycardia originating from noncoronary cusp

In this article, we report 2 young patients (a 15-year-old adolescent girl and a 25-year-old man) with drug-refractory palpitations. Admission electrocardiograms showed runs of ventricular tachycardia with left bundle-branch block morphology, left inferior axis, early precordial QRS transition, and positive QRS complex in lead I. In right ventricular mapping, the earliest activation site was found in the His bundle region. Aortic root mapping showed a very early fractionated ventricular signal with large atrial potential and no His potential in the noncoronary cusp region. Radiofrequency energy application in this region resulted in tachycardia termination within 5 to 10 seconds. During a 3- to 6-month follow-up period, the patients remained asymptomatic, and the electrocardiogram showed no ventricular arrhythmias.

Electrophysiological characteristics of focal atrial tachycardia surrounding the aortic coronary cusps

BACKGROUND

Catheter ablation of atrial tachycardia (AT) arising near the coronary cusps has been reported in limited numbers of patients. We investigated the electrophysiological characteristics of these ATs in 22 consecutive patients.

METHODS AND RESULTS

This study included 22 patients (mean age ± SD, 53 ± 11 years; 86% female) with ATs arising near the aortic coronary cusps who underwent successful ablation. Activation mapping was performed during tachycardia to identify the earliest activation site. All patients achieved successful ablation through either a retrograde aortic (n=19) or a transseptal (n=3) approach. The successful ablation sites were located in the noncoronary cusp (NCC) (n=16), including 3 near the junction between the NCC and right coronary cusp. The remaining 6 cases were ablated from the left coronary cusp (LCC) (n=3) or the left atrium posterior to the LCC (n=3). For most tachycardias, there were distinctive P-wave morphological features recorded for each cusp location. Furthermore, analysis of the electrogram morphological features recorded during tachycardia at successful ablation sites revealed an atrial/ventricular (A/V) ratio >1 in 14 of 16 NCC ATs; the remaining 2, from the NCC near the junction with the right coronary cusp, showed an A/V ratio ≤ 1. At ablation sites in the LCC, the A/V ratio was <1 (4 of 6 patients) or 1 (remaining 2 patients). During a follow-up duration of 30 ± 13 months, all patients were free of arrhythmias without antiarrhythmic drugs.

CONCLUSIONS

ATs surrounding the aortic coronary cusps can be safely and effectively ablated, with good long-term outcomes. In addition to the P-wave morphological features, the A/V ratio of the local electrogram recording during tachycardia facilitated the localization of successful sites.

Electrophysiologic properties of para-Hisian atrial tachycardia

BACKGROUND

Focal atrial tachycardia (AT) originates from preferential sites, including the tricuspid and mitral annuli. AT arising from the atrioventricular annuli is initiated and terminated with programmed stimulation and is, in general, adenosine and verapamil sensitive. Para-Hisian AT arising from the apex of the triangle of Koch has been considered to be a distinct entity, characterized by unique electrophysiological properties.

OBJECTIVE

We sought to more fully delineate the electrophysiological and electrocardiographic properties of para-Hisian AT in a large series of patients.

METHODS

The study population consisted of 38 patients (63 ± 15 years; 23 female) with AT from the para-Hisian region. The ATs were focal and originated from the anteroseptal tricuspid annulus, in close proximity to the His bundle recording. Proximity to the His bundle was confirmed by electrogram recordings, fluoroscopy, and centrifugal activation during three-dimensional mapping.

RESULTS

The mean AT cycle length was 421 ± 69 ms. AT was associated with a distinct P-wave morphology that was significantly narrower than the P wave during sinus rhythm. Adenosine (5.0 ± 1.5 mg) terminated AT in 34/35 patients. Intravenous verapamil terminated AT in three of three patients. Catheter ablation was attempted in 30 patients and was successful in 26 (87%).

CONCLUSION

The para-Hisian region is a source of focal AT, with properties consistent with AT arising circumferentially along the tricuspid and mitral annuli, and should be considered a subset of this broader group of "annular" ATs. The electropharmacologic findings in para-Hisian AT are mechanistically consistent with cyclic AMP-mediated triggered activity.

Correlative anatomy for the invasive electrophysiologist: outflow tract and supravalvar arrhythmia

Radiofrequency ablation in the outflow tract and great arteries is increasingly performed to treat a variety of symptomatic cardiac arrhythmias. The regional anatomy of these structures is among the most complex of those encountered by cardiac electrophysiologists. An exact appreciation of the relationships between these overlapping structures and their proximity to the coronary arterial and conduction system is essential for rational, safe, and effective ablation for these arrhythmias. A supravalvar portion of the aorta is a unique site for arrhythmia origin where the arrhythmogenic substrate for atrial arrhythmias, ventricular arrhythmias, and accessory pathways may all be located. Discussed in this review are the main principles of outflow tract and supravalvar arrhythmia, and these are correlated with fluoroscopy, electrograms, and electrocardiography that help guide the invasive electrophysiologist.

CT applications in electrophysiology

In recent years, extraordinary advances have been made in the management of cardiac arrhythmias. Increasingly complex procedures are being performed, and the breadth of conditions for which invasive arrhythmia therapy is indicated continues to grow. In addition to atrial and ventricular ablation procedures for treating arrhythmias, implantable defibrillators and biventricular pacemakers for cardiac resynchronization therapy have made electrophysiology an important part of heart failure management.

Predictors for permanent pacemaker requirement after transcatheter aortic valve implantation with the CoreValve bioprosthesis

INTRODUCTION

Changes in atrioventricular (AV) conduction and need for permanent pacemaker (PPM) are a recognized complication after open aortic valve replacement. We hypothesized that the need for PPM after CoreValve (Corevalve Inc, Irvine, CA) can be predicted with a combination of baseline variables.

METHODS

In patients undergoing transcatheter aortic valve implantation, potential clinical, electrocardiographic and echocardiographic predictors of permanent pacing requirement were studied.

RESULTS

Between January 2007 and March 2008, 34 patients with severe symptomatic aortic stenosis were recruited in a single center. Mean age was 84.4 years (SD 5.4, range 71-93). Of 34 cases paced at baseline, 3 (8.8%) were excluded from this analysis, as was the single periprocedural mortality. Of the remaining 30, 10 underwent permanent pacemaker implantation during the same admission (33.3%). PPM was for prolonged high-grade AV block in 4 cases, episodic high-grade AV block in 5, and sinus node disease in 1. Need for pacemaker was correlated to left axis deviation at baseline (P = .004, r = 0.508) and left bundle-branch block with left axis deviation (P = .002, r = 0.548). It was related to diastolic interventricular septal dimension on transthoracic echocardiography >17 mm (P = .045, r = 0.39) and the baseline thickness of the native noncoronary cusp (P = .002, r = 0.655). A susceptibility model was generated, and if at least one of (1) left bundle-branch block with left axis deviation, (2) interventricular septal dimension >17 mm, or (3) noncoronary cusp thickness >8 mm was present, the likelihood of PPM could be predicted with 75% sensitivity and 100% specificity and a receiver operating characteristic curve area of 0.93 +/- 0.055 (P < .001).

CONCLUSIONS

After transcatheter aortic valve implantation with CoreValve, permanent pacing was performed in around a third of patients and we present preliminary concepts towards a predictive model for this phenomenon.

Atrial tachycardia initiating atrial fibrillation successfully ablated in the non-coronary cusp of the aorta

A 60-year-old woman was referred for catheter ablation of atrial fibrillation (AF). Atrial flutter and atrial tachycardia (AT) also had been clinically documented. During the electrophysiological study, the clinical AT was induced by burst atrial pacing during isoproterenol infusion and exhibited negative P waves in the inferior leads, positive P waves in leads I, aVL, and aVR, and biphasic P waves in lead V1. The AT repeatedly and spontaneously accelerated to initiate AF by causing fibrillatory conduction in the atria. Successful catheter ablation of the AT was achieved in the non-coronary cusp of the aorta (NCC) where the local atrio-ventricular electrogram amplitude ratio was >1 during both the AT and sinus rhythm. The tailored approach targeting the NCC AT alone without left atrial ablation completely eliminated the AF. In catheter ablation of AF in a patient with a co-existing clinical AT, it may be recommended to examine the clinical AT first. If the clinical AT initiates the AF and local atrial activations in the His bundle region precede the P wave onset during AT, mapping in the NCC should be considered prior to left atrial catheterization.

Quantitative analysis and characteristics of the electrograms recorded within the non-coronary aortic sinus of Valsalva

BACKGROUND

Some supraventricular tachycardias could be ablated from the non-coronary sinus of Valsalva (NSV). However, the characteristics of the NSV electrograms have not been clarified.

METHODS AND RESULTS

A quantitative analysis of the NSV electrograms was performed in 5 patients with tachycardias arising from near the atrioventricular node (AVN) and the His-bundle region, and in 20 control subjects. In another 7 control subjects, the NSV electrograms were compared with those recorded at the left and right sinus of Valsalva (LSV and RSV). The NSV electrograms during sinus rhythm had a larger atrial amplitude than ventricular amplitude, and the ratio of the atrial amplitude to the ventricular amplitude was usually >1, which was apparently different from the LSV and RSV electrograms. A tiny but distinct His-bundle deflection was sometimes recorded at the NSV during sinus rhythm while it was not during the tachycardia. The distance to the His-bundle region in the anteroseptal right atrium was shorter from the NSV than from the RSV or LSV.

CONCLUSIONS

The precise identification of the catheter position at the NSV is possible using the characteristics of the electrograms. Much attention should be paid during ablation to the NSV because of its vicinity to the AVN and His-bundle region.