Atrial tachycardias originating from the atrial septum: electrophysiologic characteristics and radiofrequency ablation

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

BACKGROUND

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

OBJECTIVES

The goals of this study were 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 men (25%); mean age 62.6 ± 14.7 years] with PSAT ablation in 4 tertiary medical centers were assigned to 3 groups according to the ablation site: right atrial (RA) para-Hisian region (group 1, n = 10), noncoronary cusp (NCC) (group 2, n = 13), and left atrial (LA) paraseptal area (group 3, n = 21). Multiple-chamber activation mapping was performed guided by a 3-dimensional navigation system. The discrepancies in the earliest activation time between 2 of 3 chambers (ΔRA-LA, ΔRA-NCC, and ΔLA-NCC) were calculated in each group and used for pairwise comparisons.

RESULTS

There was a significant difference in ΔRA-LA, ΔRA-NCC, and ΔLA-NCC among the 3 groups. ΔRA-LA was the only parameter that could consistently predict the ablation site of PSAT with good accuracy (area under the curve 1.000, sensitivity 100% and specificity 100%, and cutoff value 7 ms for predicting right para-Hisian or NCC ablation; area under the curve 0.974, sensitivity 92.3% and specificity 95.2%, and cutoff value -4 ms for predicting NCC or left paraseptal ablation). Based on 2 cutoff values, a 2-step algorithm was developed to predict the ablation site of PSAT with a positive predictive value of 95.4% and a negative predictive value of 97.0%.

CONCLUSION

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

Case report: A case of perinodal atrial tachycardia and review of the relevant clinical anatomy surrounding the retroaortic node

A 70-year-old female presented with incessant supraventricular tachycardia that was refractory to metoprolol and sotalol. ECG revealed a narrow complex tachycardia with a rate of 163 beats per minute with a short RP relationship. She had salvos of atrial tachycardia which led to a severe reduction in ejection fraction as noted on echocardiography and hemodynamic instability. An electrophysiological study was performed, and findings suggested this to be an atrial tachycardia with earliest activation in the perinodal area. Radiofrequency ablation was carried out along the septum and associated structures to surround this region including the right atrium, non-coronary sinus of Valsalva, and the left atrium (anterior wall outside of the right superior pulmonary vein) to isolate this area and surround the focus with ablation lesions. The patient has done well post-procedure and continues to do well without any recurrence on low-dose flecainide at 8 months.

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.

P-Wave Morphology in Focal Atrial Tachycardia: An Updated Algorithm to Predict Site of Origin

OBJECTIVES

This study sought to report P-wave morphology (PWM) from a series of paraseptal (PS) atrial tachycardia (AT), revise then prospectively evaluate a simplified PWM algorithm against a contemporary consecutive cohort with focal AT.

BACKGROUND

The 2006 PWM algorithm was useful in predicting the origin of focal AT. An updated algorithm was developed given advances in multipolar 3-dimensional mapping, potential limitations of PWM in separating PS sites, and a renewed interest in the P-wave in mapping non-pulmonary vein triggers.

METHODS

The PWM from a consecutive series of 67 patients with PS AT were analyzed. PS sites included were coronary sinus ostium, perinodal, left and right septum, septal tricuspid annulus, superior mitral annulus, and noncoronary cusp. Next the P-wave algorithm was revised and prospectively evaluated by 3 blinded assessors.

RESULTS

The P-wave for PS sites was neg/pos (n = 50), iso/pos (n = 10), or isoelectric (n = 4) in lead V₁ (96%). The P-wave algorithm was modified and prospectively applied to 30 consecutive patients with focal AT who underwent successful ablation. Foci (n = 30) originated from the right atrium (33.3%), left atrium (30%), and PS (36.7%). Using the PW algorithm, the correct anatomic location was identified in 93%. Incorrect interpretation of the terminal positive P-wave component (n = 3) and initial negative P-wave deflection (n = 1) in lead V₁ misidentified 4 paraseptal cases.

CONCLUSIONS

The revised PWM algorithm offers a simplified and accurate method of localizing the responsible site for focal AT. The P-wave remains an important first step in mapping atrial arrhythmias.

Catheter Ablation of Focal Atrial Tachycardia with Early Activation Close to the His-Bundle from the Non Coronary Aortic Cusp

Fundamento

A ablação da taquicardia atrial (TA) com local de ativação mais precoce próxima ao feixe de His é um desafio, devido ao risco de bloqueio de AV completo por sua proximidade ao sistema de His-Purkinje (SHP). Uma alternativa para minimizar esse risco é posicionar o cateter na cúspide não coronária (CNC), que é anatomicamente contígua à região para-Hissiana.

Objetivos

O objetivo deste estudo foi fazer uma revisão de literatura e avaliar as características eletrofisiológicas, a segurança e o índice de sucesso de aplicação de radiofrequência (RF) por cateter na CNC para o tratamento de TA para-Hissiana em uma série de casos.

Métodos

Avaliamos retrospectivamente dez pacientes (Idade: 36±10 anos) que foram encaminhados para ablação de taquicardia paroxística supraventricular (TPSV) e haviam sido diagnosticados com TA focal para-Hissiana confirmada por manobras eletrofisiológicas clássicas. Para a análise estatística, um P valor d <0.05 foi considerado estatisticamente significativo.

Resultados

A ativação atrial mais precoce na posição His foi de 28±12ms da onda P, e a CNC foi 3±2ms antes da posição His, sem evidência de potencial His em todos os pacientes. Foi aplicada RF à CNC (cateter de ponta de 4-mm; 30W, 55°C) e a taquicardia foi interrompida em 5±3s sem aumento no intervalo PR ou evidência de um ritmo juncional. Os testes eletrofisiológicos não induziram novamente a taquicardia em 9/10 pacientes. Não houve complicações em nenhum procedimento. Durante o período de acompanhamento de 30 ± 12 meses, nenhum paciente apresentou recorrência de taquicardia.

Conclusão

O tratamento percutâneo de TA para-Hissiana por meio de CNC é uma estratégia segura e eficiente, tornando-se uma opção interessante para o tratamento de arritmia complexa. (Arq Bras Cardiol. 2021; 116(1):119-126)

Focal atrial tachycardia ablation: Highly successful with conventional mapping

BACKGROUND/OBJECTIVE

Radiofrequency catheter ablation (RFCA) of focal atrial tachycardia (FAT) traditionally is guided by conventional endocardial mapping of earliest atrial activation; however, more recently electro-anatomical mapping is heralded as a more effective, albeit more expensive, tool to guide ablation. Herein we present the results of conventional mapping-guided RFCA. Apropos, we conducted a literature search of studies reporting > 10 FAT patients submitted to RFCA.

METHODS AND RESULTS

Conventional mapping-guided RFCA, performed in 63 FAT patients (aged 42.4 + 17.3 years; 14 with incessant tachycardia and 12 with tachycardiomyopathy (TCM)), was successful in 61 (96.8%) patients, applied for single foci in 59 (93.7%) and two foci in 4 patients, right (n = 46) or left sided (n = 17). The earliest atrial activation time at the ablation site was 41.3 ± 16.2 ms. Fluoroscopy time averaged 27.3 + 18.7 min, and procedure lasted 2.6 + 1.7 h. Complications occurred in two patients (sinus pauses in one needing a pacemaker and a large inguinal hematoma in one). Over 29.0 + 22.9 months, four patients (6.5%) had recurrences, of whom three were successfully re-ablated. All patients with TCM showed gradual improvement to normalization over 4-6 months. Literature search showed that RFCA success is equally high when guided with either conventional (88.5%) or electro-anatomical mapping (90%) with similar recurrences (9.6% vs. 9.5%).

CONCLUSION

Conventional mapping-guided RFCA of FAT had high success (96.8%) with low complication (3.2%) and recurrence rates (6.5%). TCM was fully reversible. These results are comparable to those achieved with the more expensive electro-anatomical mapping, which may be reserved for more complex cases or for those failing the conventional approach.

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.

Techniques for the provocation, localization, and ablation of non-pulmonary vein triggers for atrial fibrillation

The end point of current catheter-based ablation approaches for the treatment of atrial fibrillation (AF) is the elimination of all the possible triggers with the least amount of ablation necessary. Once all the triggers have been eliminated, the incremental value of any additional lesion sets remains to be proven. Pulmonary vein (PV) isolation is the cornerstone of catheter ablation approaches for eliminating AF triggers. However, up to 11% of patients demonstrate reproducible sustained AF initiation from non-PV foci. In these patients, triggers can typically be elicited using standardized induction protocols, which include cardioversion of spontaneous and/or induced AF and infusion of high-dose isoproterenol. Non-PV triggers typically arise from discrete anatomical structures that include the mitral and tricuspid periannular regions, the crista terminalis and Eustachian ridge, the interatrial septum, the left atrial (LA) posterior wall, the left atrial appendage (LAA), and other thoracic veins such as the superior vena cava, the coronary sinus, and the ligament of Marshall. Localization of non-PV foci involves a detailed analysis of specific intra-atrial activation sequences using multipolar catheters in standard atrial locations coupled with information from the surface electrocardiogram P wave when possible. Multipolar catheters positioned along the coronary sinus and crista terminalis/superior vena cava region together with direct recordings from the right and left PVs allow a quick localization of non-PV foci. Elimination of non-PV triggers by means of focal ablation at the site of origin or isolation of arrhythmogenic structures (eg, LA posterior wall or superior vena cava) has been associated with improved arrhythmia-free survival.

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.

Electrocardiographic diagnosis of atrial tachycardia: classification, P-wave morphology, and differential diagnosis with other supraventricular tachycardias

Atrial tachycardia is defined as a regular atrial activation from atrial areas with centrifugal spread, caused by enhanced automaticity, triggered activity or microreentry. New ECG classification differentiates between focal and macroreentrant atrial tachycardia. Macroreentrant atrial tachycardias include typical atrial flutter and other well characterized macroreentrant circuits in right and left atrium. Typical atrial flutter has been described as counterclockwise reentry within right atrial and it presents a characteristic ECG "sawtooth" pattern on the inferior leads. The foci responsible for focal atrial tachycardia do not occur randomly throughout the atria but tend to cluster at characteristic anatomical locations. The surface ECG is a very helpful tool in directing mapping to particular areas of interest. Atrial tachycardia should be differentiated from other supraventricular tachycardias. We propose a diagnostic algorithm in order to help the physician to discriminate among those. Holter analysis could offer further details to differentiate between atrial tachycardia and another supraventricular tachycardia. However, if the diagnosis is uncertain, it is possible to utilize vagal maneuvers or adenosine administration. In conclusion, in spite of well-known limits, a good interpretation of ECG is very important and it could help the physician to manage and to treat correctly patients with atrial tachycardia.

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.

Left septal atrial tachycardias: electrocardiographic and electrophysiologic characterization of a paraseptal focus

OBJECTIVE

The objective was to characterize the electrocardiographic and electrophysiological features of focal atrial tachycardia (FAT) originating from the left septum (LS).

BACKGROUND

FAT is recognized to occur at predefined anatomic locations rather than randomly throughout the atria. We describe the ECG and EP features of ATs originating from the LS as an important site for apparent perinodal tachycardias.

METHODS

Nine patients presenting with LS FAT from a consecutive series of 384 underwent EP/RFA for symptomatic FAT.

RESULTS

The mean age was 56 ± 12 years; 7 female with symptoms for 36 ± 28 months. P wave morphology (PWM) was negative/positive in lead V1 and across the precordial leads and negative or negative/positive in inferior leads in all patients. Tachycardia was incessant in 6 out of 9 patients with a mean tachycardia cycle length 421 ± 56 milliseconds. His A was ahead of P wave in all patients (mean -15 ± 5 milliseconds) and earlier than CS proximal (mean 4 ± 9 milliseconds). Successful acute focal ablation achieved at a mean of 31 ± 12 milliseconds ahead of P wave with no recurrences at a mean follow-up of 30 ± 28 months.

CONCLUSION

Although the left septum is an uncommon site for focal AT an awareness of this location for harboring foci is particularly important when mapping apparently right-sided septal tachycardias.

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.

Focal atrial tachycardia arising from the right atrial appendage: electrophysiologic and electrocardiographic characteristics and catheter ablation

BACKGROUND

Focal atrial tachycardia (AT) arising from the crista terminalis, pulmonary veins, para-Hisian region, tricuspid annulus and coronary sinus ostium regions are well described. Less information exists regarding AT arising from the right atrial appendage (RAA).

OBJECTIVE

The study was done to characterise the electrocardiographic and electrophysiologic features and radiofrequency ablation (RFA) of focal AT arising from the RAA.

METHODS

Six patients of a consecutive series of 250 patients undergoing RFA for focal AT are reported. Mapping was performed during tachycardia or frequent atrial ectopy to identify the earliest activation in the atria. Atrial appendage angiography was performed to identify the origin in the RAA after RFA.

RESULTS

All the six (2.4%) patients (four women; mean age 26 +/- 11 years) had tachycardia originating from RAA. The tachycardia demonstrated a characteristic P-wave morphology and endocardial activation pattern. P-wave morphology was upright in I, II, III and aVF, inverted in aVR, inverted or isoelectric in aVL. Lead V1 showed a negative component and lead V4-V6 showed an upright component in all the patients. The earliest endocardial activity occurred at the high right atria in all the patients. The earliest endocardial activation at the successful RFA site occurred 48 +/- 18 ms before the onset of the P wave. RFA was highly successful in all the six patients. Long-term success was achieved in six of the six patients over a mean follow-up of 24 +/- 5 months.

CONCLUSIONS

The RAA is an uncommon site of origin for focal AT 2.4%. There is consistent P-wave morphology and endocardial activation associated with this type of AT. Using mapping targeted to anatomic structures achieved a high success rate for ablation. Irrigated-tip catheter may be helpful for patients who had a recurrence.

Successful catheter ablation of atrial tachycardia originating from the non-coronary aortic sinus

We report a rare case of atrial tachycardia originating from the non-coronary aortic sinus. After failed radiofrequency (RF) energy applications at right His-bundle region, the complete elimination of atrial tachycardia was achieved with an RF energy application in the non-coronary aortic sinus. With the review of other papers, this report emphasizes the importance of mapping in the non-coronary aortic sinus in focal atrial tachycardia near the atrioventricular node or near the His-bundle.

Electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia arising from superior tricuspid annulus

OBJECTIVES

This study describes the electrophysiologic and electrocardiographic characteristics of focal atrial tachycardia (AT) arising from superior tricuspid annulus in six (1.9%) patients of a consecutive series of 320 patients.

METHODS

Six patients (mean age 42 +/- 22 years) with a mean cycle length of 326 ms of a consecutive series of 320 patients undergoing radiofrequency ablation for focal AT were mapped.

RESULTS

During electrophysiologic study, tachycardia could be induced in five patients with programmed atrial extrastimuli while a spontaneous onset and offset with 'warm-up and cool-down' phenomenon was seen in the other patient. During tachycardia, P-wave morphology in Lead I, II, III and aVF was upright in all the six patients. The precordial leads were dominantly negative or isoelectric in V(1)-V(2) and positive in V(5)-V(6) with a transition at V(3) or V(4). Moreover, the tachycardia was sensitive to intravenous administration of adenosine triphosphate in five of six patients.

CONCLUSIONS

Radiofrequency ablation was performed successfully in all patients (mean 4.5 +/- 1.2 applications). No recurrence of AT was observed after a mean follow-up of 8 +/- 6 months. Thus, AT arising from superior tricuspid annulus is rare. Radiofrequency ablation of this kind of AT is safe and effective.

Focal Atrial Tachycardia Originating from the Left Atrial Appendage: Electrocardiographic and Electrophysiologic Characterization and Long-Term Outcomes of Radiofrequency Ablation

INTRODUCTION

This study sought to investigate electrophysiologic characteristics and radiofrequency ablation (RFA) in patients with focal atrial tachycardia (AT) arising from the left atrial appendage (LAA).

METHODS

This study included seven patients undergoing RFA with focal AT. Activation mapping was performed during tachycardia to identify an earlier activation in the left atria and the LAA. The atrial appendage angiography was performed to identify the origin in the LAA before and after RFA.

RESULTS

AT occurred spontaneously or was induced by isoproterenol infusion rather than programmed extrastimulation and burst atrial pacing in any patient. The tachycardia demonstrated a characteristic P-wave morphology and endocardial activation pattern. The P wave was highly positive in inferior leads in all patients. Lead V1 showed upright or biphasic (+/-) component in all patients. Lead V2-V6 showed an isoelectric component in five patients or an upright component with low amplitude (<0.1 mV) in two patients. Earliest endocardial activity occurred at the distal coronary sinus (CS) ahead of P wave in all seven patients. Mean tachycardia cycle length was 381 +/- 34 msec and the earliest endocardial activation at the successful RFA site occurred 42.3 +/- 9.6 msec before the onset of P wave. RFA was acutely successful in all seven patients. Long-term success was achieved in seven of the seven over a mean follow-up of 24 +/- 5 months.

CONCLUSIONS

The LAA is an uncommon site of origin for focal AT (3%). There were consistent P-wave morphology and endocardial activation associated with this type of AT. The LAA focal ablation is safe and effective. Long-term success was achieved with focal ablation in all patients.

Focal Atrial Tachycardias Arising from the Right Atrial Appendage: Electrocardiographic and Electrophysiologic Characteristics and Radiofrequency Ablation

OBJECTIVE

To characterize the electrocardiographic and electrophysiological features and frequency of focal atrial tachycardia (AT) originating from the right atrial appendage (RAA).

BACKGROUND

The RAA has been described as a site of origin of AT, but detailed characterization of these tachycardias is limited.

METHODS

Ten patients (3.8%) of 261 undergoing radiofrequency ablation (RFA) for focal AT are reported. Endocardial activation maps (EAM) were recorded from catheters at the CS (10 pole), tricuspid annulus (20 pole Halo catheter), and His positions. P waves were classified as negative, positive, isoelectric, or biphasic.

RESULTS

The mean age was 39 +/- 20 years, nine males, with symptoms for 4.1 +/- 5.1 years. Tachycardia was incessant in seven patients, spontaneous in one patient, and induced by programmed extrastimuli in two patients. These foci had a characteristic P wave morphology. The P wave was negative in lead V(1) in all patients, becoming progressively positive across the precordial leads. The P waves in the inferior leads were low amplitude positive in the majority of patients. Earliest EAM activity occurred on the Halo catheter in all patients. Mean activation time at the successful RFA site =-38 +/- 15 msec. Irrigated catheters were used in six patients, due to difficulty achieving adequate power. RFA was acutely successful in all patients. Long-term success was achieved in all patients over a mean follow up of 8 +/- 7 months.

CONCLUSIONS

The RAA is an uncommon site of origin for focal AT (3.8%). It can be suspected as a potential anatomic site of AT origin from the characteristic P wave and activation timing. Irrigated ablation catheters are often required for successful ablation. Long-term success was achieved with focal ablation in all patients.

Electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia arising from para-Hisian region

This study describes the electrophysiologic characteristics and radiofrequency ablation of focal atrial tachycardia (AT) arising from para-Hisian region in 14 (6.0%) patients of a consecutive series of 224 patients patients. Inverted or biphasic P wave in V(1) and uncharacteristic P wave in inferior leads were observed during tachycardia, suggesting that there isn't a characteristic P-wave morphology for para-Hisian AT. During electrophysiological study, tachycardia could be induced with programmed atrial extrastimuli in 11 patients while a spontaneous onset and offset with "warm-up and cool-down" phenomenon were seen in other three patients. Moreover, the tachycardias were sensitive to intravenous administration of adenosine triphosphate in all patients. On the basis of these findings, the mechanism is suggestive of triggered activity or micro-reentry, but automaticity cannot be conclusively excluded. Radiofrequency energy was delivered to the earliest site of atrial activation during AT. Ablating energy was carefully titrated, starting at 5 W and increasing gradually upto a maximum of 40 W, to achieve the ceasing of tachycardia. The long-term outcome was a 100% success rate in these 14 patients and there were no irreversible complications associated with ablation. Thus, the mapping and ablation of focal AT arising from para-Hisian region is safe and effective, delivery of radiofrequency energy in a titrated manner and continuous monitoring of atrioventricular (AV) conduction advocated to minimise the risk of damage to the anterograde AV conduction.

P-wave morphology in focal atrial tachycardia: development of an algorithm to predict the anatomic site of origin

OBJECTIVES

The purpose of this study was to perform a detailed analysis of the P-wave morphology (PWM) in focal atrial tachycardia (AT) and construct and prospectively evaluate an algorithm for identification of the anatomic site of origin.

BACKGROUND

Although smaller studies have described the PWM from particular anatomic locations, a detailed algorithm characterizing the likely location of a tachycardia associated with a P-wave of unknown origin has been lacking.

METHODS

The PWMs for 126 consecutive patients undergoing successful radiofrequency ablation of 130 ATs are reported. P waves were included only when the onset was preceded by a discernible isoelectric segment. P waves were classified as positive (+), negative (-), isoelectric, or biphasic. Sensitivity, specificity, and predictive values were calculated. On the basis of these results, an algorithm was constructed and prospectively evaluated in 30 new consecutive ATs.

RESULTS

The distribution of ATs was right atrial (RA) in 82 of 130 (63%) and left atrial (LA) in 48 of 130 (37%). Right atrial sites included crista (n = 28), tricuspid annulus (n = 29), coronary sinus (CS) ostium (n = 14), perinodal (n = 7), right septum (n = 1), and RA appendage (n= 3). Left atrial sites included pulmonary veins (n = 32), mitral annulus (n = 8), CS body (n= 3), left septum (n = 3), and LA appendage (n = 2). In electrocardiographic lead V1, a negative or +/- P-wave demonstrated a specificity of 100% for a RA focus, and a + or -/+ P-wave demonstrated a sensitivity of 100% for a LA focus. A characteristic PWM was associated with high sensitivity and specificity at common atrial sites for tachycardia foci. A P-wave algorithm correctly identified the focus in 93%.

CONCLUSIONS

Characteristic PWMs corresponding to known anatomic sites for focal AT are associated with high specificity and sensitivity. A P-wave algorithm correctly identified the site of tachycardia origin in 93%.

Focal Atrial Tachycardia Originating From the Non-Coronary Aortic Sinus

OBJECTIVES

We sought to investigate electrophysiological characteristics and catheter ablation in patients with focal atrial tachycardia (AT) originating from the non-coronary aortic sinus (AS).

BACKGROUND

In patients with failed ablation of focal AT near the His bundle (HB) region, an origin from the non-coronary AS should be considered because of the close anatomical relationship.

METHODS

This study included 9 patients with focal AT, in 6 of whom attempted radiofrequency (RF) ablation had previously failed. Activation mapping was performed during tachycardia to identify an earliest activation in the atria and the AS. The aortic root angiography was performed to identify the origin in the AS before RF ablation.

RESULTS

Focal AT was reproducibly induced by atrial pacing. Mapping in atria demonstrated that the earliest atrial activation was located at the HB region, whereas mapping in the non-coronary AS demonstrated that an earliest atrial activation preceded the atrial activation at the HB by 12.2 +/- 6.9 ms and was anatomically located superoposterior to the HB in all 9 patients. Also, His potentials were not found at the successful site in the non-coronary AS in all 9 patients. The focal AT was terminated in <8 s in all 9 patients. Junctional beats and PR prolongation did not occur during RF application in all 9 patients. No complications occurred in any of the nine patients. All 9 patients were free of arrhythmias without antiarrhythmic drugs during a follow-up of 9 +/- 3 months.

CONCLUSIONS

In patients with focal AT near the HB region, mapping in the non-coronary AS can improve clinical outcome.

Focal Atrial Tachycardia II: Management

Over the last decade there have been significant changes in the treatment of focal atrial tachycardia (AT). This review concentrates on the different approaches to the treatment of focal AT. Initial therapies included antiarrhythmic medications and surgery. However, with the advent of radiofrequency ablation, and the poor efficacy of pharmacological therapy, there has been a shift toward a primary ablative approach. Several different mapping techniques have been proposed. The different techniques, including P-wave morphology and advanced three-dimensional mapping, are discussed in this review.

Focal Atrial Tachycardia I: Clinical Features, Diagnosis, Mechanisms, and Anatomic Location

Atrial tachycardia (AT) may be focal or macroreentrant. In this review we will concentrate on focal AT. The diagnosis of focal AT may be made from a standard electrocardiogram (ECG); however, in some cases differentiation from other forms of supraventricular tachycardia may be difficult. Focal AT may be due to several different mechanisms, including abnormal automaticity, triggered activity, and microreentry. Focal AT does not occur randomly throughout the atria but has a characteristic anatomic distribution. In this review, we particularly focus on the clinical features, diagnosis, mechanisms, and anatomic location of focal AT.

Adenosine-sensitive atrial tachycardia originating from the proximal coronary sinus

BACKGROUND

Atrial tachycardia (AT) can originate from the proximal coronary sinus (CS). However, detailed electrophysiologic characteristics of the tachycardia are not available.

OBJECTIVES

We describe the electrophysiologic characteristics, response to adenosine 5'-triphosphate, and results of radiofrequency ablation of AT with the earliest activation in the proximal CS.

METHODS

In 7 of 54 patients (age 57 +/- 18 years) with nonmacroreentrant "focal" AT undergoing electrophysiologic study and radiofrequency ablation, the earliest atrial activation site was located in the proximal CS.

RESULTS

The earliest activation site was inside the CS 13 +/- 3 mm from the ostium. The AT could be induced and terminated by atrial extrastimuli or burst pacing. In all patients, the AT was also terminated by a very small dose of adenosine 5'-triphosphate (4.2 +/- 1.1 mg). Rapid ventricular pacing during the tachycardia produced ventriculoatrial dissociation. Radiofrequency ablation directed at the earliest atrial activation site was effective in only three patients (group A). In the remaining four patients (group B), after the radiofrequency energy deliveries, the earliest activation site shifted to an adjacent site with a small increase in the cycle length. Three group B patients underwent successful ablation in the slow pathway region. No recurrence was observed over a follow-up period of 22 +/- 5 months.

CONCLUSION

AT with earliest activation in the proximal CS is sensitive to a small dose of adenosine 5'-triphosphate. In some patients, radiofrequency applications in the slow pathway region are effective even if the local activation is not early.

Characterization of Focal Atrial Tachycardia Using High-Density Mapping

OBJECTIVES

The goal of this study was to characterize the origin of focal atrial tachycardias (AT).

BACKGROUND

Focal ATs originate from a small area and spread centrifugally; however, activation at the AT origin has not been characterized.

METHODS

Twenty patients with AT having failed prior ablation or occurring after atrial fibrillation ablation were studied. After excluding macro-re-entry, AT was mapped using a 20-pole catheter (five radiating spines; diameter 3.5 cm), performing vector mapping to identify the earliest activity followed by high-density mapping at the AT origin. Localized re-entry was considered if >85% of the tachycardia cycle length (CL) was observed within the mapping field and was confirmed by entrainment.

RESULTS

A total of 27 ATs were mapped to the pulmonary vein ostia (n = 5), and left (n = 16) and right atria (n = 6). A localized focus was evidenced at the site of origin in 19 ATs (70%), whereas in 8 (30%), localized re-entry was evidenced by 95.2 +/- 4.5% of the tachycardia CL recorded within the mapping field and entrainment showed a post-pacing interval <20 ms longer than tachycardia CL (6 of 6 tested). Localized re-entry had a shorter CL (p = 0.009), slowed conduction at its origin (fractionated potential 115 +/- 19 ms vs. 64 +/- 22 ms, representing 49 +/- 10% and 20 +/- 10% of tachycardia CL, respectively; p < 0.0001), and were more often contiguous with regions of electrical silence or conduction abnormalities (88% vs. 32%; p = 0.01). In addition, mapping documented varying degrees of intra-atrial conduction block, preferential conduction (n = 5), and rapid bursts of myocardial activity (n = 1). At 11 +/- 7 months, none have had recurrence of AT.

CONCLUSIONS

High-density multielectrode mapping can be used to perform vector mapping to localize complex AT. It provides novel insight into the mechanisms of focal AT, distinguishing focal AT from localized re-entry.

Focal Atrial Tachycardia From the Ostium of the Coronary Sinus

OBJECTIVES

The goal of this study was to characterize the electrocardiographic and electrophysiologic features and frequency of focal atrial tachycardia (AT) originating from the coronary sinus ostium (CS).

BACKGROUND

The ostium of the coronary sinus has been described as a site of origin of AT, but detailed characterization of these tachycardias is limited.

METHODS

Thirteen patients (6.7%) of 193 undergoing radiofrequency ablation (RFA) for focal AT are reported. Endocardial activation maps (EAM) were recorded from catheters at the CS (10 pole), crista terminalis (20 pole), and His positions. The P waves were classified negative, positive, isoelectric, or biphasic.

RESULTS

The mean age was 41 +/- 6 years, seven female patients, with symptoms for 8 +/- 3 years. Tachycardia was induced by programmed extra-stimuli in eight patients, was spontaneous in three patients, and in response to isoproterenol in two patients. These foci had a characteristic P-wave morphology. At the CS ostium, the P-wave was deeply negative in all inferior leads, negative or isoelectric becoming positive in lead V(1), then progressively negative across the precordium. Lead aVL was positive in all patients. Earliest EAM activity occurred at the proximal CS at 20 +/- 3 ms ahead of P-wave. Mean activation time at the successful RFA site = -36 +/- 8 ms; RFA was acutely successful in 11 of 13 patients. Long-term success was achieved in 11 of 11 over a median follow-up of 25 +/- 4 months.

CONCLUSIONS

The CS ostium is an uncommon site of origin for focal AT (6.7%). It can be suspected as a potential anatomic site of AT origin from the characteristic P-wave and activation timing. Long-term success was achieved with focal ablation in the majority of patients.

Successful catheter ablation of atrial tachycardia originating near the atrioventricular node from the noncoronary sinus of Valsalva

This report describes a patient who underwent RF catheter ablation of atrial tachycardia. Two applications of RF energy near the His-bundle region transiently terminated the tachycardia. With detailed mapping at the aortic sinus of Valsalva using a retrograde transaortic approach, the earliest atrial activation was found in the noncoronary sinus of Valsalva. Complete elimination of the tachycardia was achieved with RF energy application from this site.

Outcome of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation

OBJECTIVES

The aim of this study was to determine the long-term results of ablation for sustained focal atrial tachycardia in patients with and without a history of atrial fibrillation.

METHODS

A history of atrial fibrillation was documented in 25 of 111 patients (23%) with focal atrial tachycardias. We studied the results of focal ablation during a follow-up of 27 +/- 22 months.

RESULTS

Enlargement of left atrium (Odds ratio 2.99) and septal origin of the atrial focus (Odds ratio 5.68) were independent predictors of coexisting atrial fibrillation. Patients with a septal origin of the focal atrial tachycardia were older (62 vs. 54 years) and had a higher rate of structural heart disease than patients with a non-septal site of origin (51 vs. 29%). A higher rate of atrial fibrillation was found in patients with anteroseptal (56%), midseptal (50%) and posteroseptal (36%) atrial tachycardias than in patients with focal atrial tachycardias arising from the crista terminalis (9%), the tricuspid (12%) and mitral annulus (0%), the ostia of thoracic veins (17%) and other right atrial (27%) and left atrial free wall sites (10%). During the follow-up, atrial fibrillation was documented in 3% of patients without preexisting atrial fibrillation. In patients with focal atrial tachycardia and a history of atrial fibrillation, at least one episode of atrial fibrillation was documented during follow-up in 64% of patients, but 60% of patients reported marked symptomatic improvement.

CONCLUSION

An increased rate of coexisting atrial fibrillation was found in patients with a septal origin of focal atrial tachycardia. Ablation of the focal atrial tachycardia may eliminate both arrhythmias, but patients with a history of atrial fibrillation may still be prone to recurrences of atrial fibrillation after focal ablation.

Influence of High-Pass Filtering on Noncontact Mapping and Ablation of Atrial Tachycardias

The aim of the study was to define the impact of different high-pass filter settings (HPF) on the accuracy of mapping of ectopic atrial tachycardias (EAT) using a noncontact mapping (NCM) system. In 20 patients with 22 EAT a noncontact probe was deployed in the right (n = 19) or in the left atrium (n = 3). The device enables interpolation and analysis of unipolar electrograms. It provides information on focus localization and signal morphology. These parameters were compared in different HPF of 0.5 Hz, 2 Hz, 8 Hz, and 16 Hz. The NCM signal morphology was preserved at all HPF. An initial negative deflection recorded by NCM system showed a positive predictive value of 93% regarding the ablation success. The deviation (spatial disparity) between visualized focus origin and successful ablation site was 6.9 +/- 5.4 mm. Between two consecutive filter settings, the focus shift was more pronounced between 0.5 and 2 Hz (5.4 +/- 4.5 mm) compared to a setting between 8 and 16 Hz (2.9 +/- 2.9 mm; P < 0.05). Successful ablation was achieved in 15/18 right atrial tachycardias (83%) and in 2/3 left atrial arrhythmias. Different HPF influence NCM spatial analysis of EAT. However, a small variability in foci localization does not impact final ablation results.

Clinical and electrophysiologic characteristics of left septal atrial tachycardia

OBJECTIVES

It was the purpose of this study to define the electrophysiologic (EP) identity of left septal atrial tachycardia (AT).

BACKGROUND

The clinical and EP characteristics of this particular type of arrhythmia have not been fully described.

METHODS

A total of 120 patients with AT underwent invasive EP evaluation. Five patients (two men and three women; mean age 49 +/- 15 years) with left septal AT were identified. Mapping of the right and left atrium was performed using conventional electrode catheters (five patients) and a three-dimensional electroanatomic mapping system (three patients) followed by radiofrequency (RF) ablation at the earliest site of local endocardial activation.

RESULTS

Five tachycardias with a mean cycle length of 320 +/- 94 ms were mapped, and the earliest endocardial electrogram occurred 22 +/- 10 ms before the onset of the surface P-wave. Three left septal ATs were found to be originating from the left inferoposterior atrial septum and two from the left midseptum. During tachycardia, positive (three patients), biphasic negative-positive deflection (one patient), or isoelectric (one patient) P waves were recorded in lead V(1). The inferior leads demonstrated a positive or biphasic P-wave morphology in four of five patients (80%). Four patients were given both adenosine and verapamil during AT. In three of four patients, verapamil successfully terminated AT after adenosine had failed. Adenosine successfully terminated AT in one of four patients. Successful RF ablation was performed in all patients (mean 2.2 +/- 1.7 RF applications) without affecting atrioventricular conduction properties. No recurrence of AT was observed after a mean follow-up of 14 +/- 8 months.

CONCLUSION

Left septal AT ablation is safe and effective. There was no consistent P-wave morphology associated with this particular type of AT. This arrhythmia appears to be resistant to adenosine and moderately responsive to calcium antagonists.

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.