Registro Español de Ablación con Catéter. XIII Informe Oficial de la Sección de Electrofisiología y Arritmias de la Sociedad Española de Cardiología (2013)

Spanish catheter ablation registry. 23rd official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2023)

INTRODUCTION AND OBJECTIVES

We report the results of the 2023 Spanish catheter ablation registry.

METHODS

Procedural data were collected and incorporated into the REDCap platform by all participating centers through a specific form.

RESULTS

There were 104 participating centers in 2023 compared with 103 in 2022. In 2023, the total number of ablation procedures was 26 207, indicating a stabilization of the increase observed in 2022 following the pandemic. The increase was mainly due to procedures for atrial fibrillation (AF), with a total of 9942 ablations, representing 38% of all substrates. Notably, pulse-field ablation represented 10.3% of all AF ablation procedures, leading single-shot ablation strategies to outnumber point-by-point AF ablation for the first time in the history of the registry. Cavotricuspid isthmus ablation remained the second most targeted substrate (19% of all substrates, n=5067). The overall acute success rate remained high (97%), with a downward trend in the complication rate (1.6% vs 1.8% in 2022) and mortality rate (0.03%; n=7). Compared with 2022, there was a significant increase in procedures performed using electro-anatomical mapping and zero-fluoroscopy techniques for cavotricuspid isthmus ablation (52% vs 26%), AV node re-entrant tachycardia (48% vs 34%), and accessory pathways (62% vs 22%). We registered 466 ablations in pediatric patients.

CONCLUSIONS

The data indicate a stabilization in the post-pandemic increase in ablation procedures, with an absolute and relative increase in AF as the predominant substrate. Success rates remained stable with a modest reduction in complication and mortality rates.

Spanish catheter ablation registry. 22nd official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2022)

INTRODUCTION AND OBJECTIVES

This article presents results of the Spanish catheter ablation registry for the year 2022.

METHODS

Data were retrospectively entered into a REDCap platform using a specific form.

RESULTS

A total of 103 centers participated (75 public, 28 private), which reported 23 360 ablation procedures, with a mean of 227±173 and a median of 202 [interquartile range, 77-312] procedures per center. Activity significantly increased (+5419 procedures,+30.2%) with more centers participating in the registry (10 more than in 2021). The most common procedure continued to be atrial fibrillation ablation (35%, 8185 procedures) followed by cavotricuspid isthmus ablation (20%, 4640 procedures), and intranodal re-entrant tachycardia (17%, 3898 procedures). There was an increase in all reported substrates, especially atrial fibrillation ablation (+40%), with slightly higher global acute success (96%) and lower complication rates (1.8%) and mortality (0.04%, n=10). In total, 525 procedures were performed in pediatric patients (2.2%) CONCLUSIONS: The Spanish catheter ablation registry systematically and continuously collects the national trajectory, which experienced a significant activity increase in 2022 in all of the reported substrates but especially in atrial fibrillation ablation. Acute success increased, while both complications and mortality decreased.

Spanish catheter ablation registry. 21st official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2021)

INTRODUCTION AND OBJECTIVES

The results of the 2021 Spanish catheter ablation registry are presented.

METHODS

Data collection was carried out retrospectively by filling in and sending a specific form by the participating centers.

RESULTS

Data from 93 centers (65 public, 28 private) were analyzed. A total of 17941 ablation procedures were reported with a mean of 193 ± 133 cases per centre. Recovery of activity from SARS-CoV-2 pandemic lockdown has led to a notable increase in the number of procedures (+2772 procedures, +18%) despite a small decrease in participating centers (4 centers less than in 2020). Atrial fibrillation ablation continues to be the leading procedure, with 5848 procedures (32,6%). Together with ablation of the cavotricuspid isthmus (3766; 21%) and atrioventricular nodal reentrant tachycardia (3132; 17,5%) they constitute the 3 most frequently approached substrates. The total success rate reported (94%) is similar to previous years with a similar rate of complications (2%) and mortality (0.07). A total of 401 procedures were performed in pediatric patients (3,8%).

CONCLUSIONS

The Spanish catheter ablation registry systematically and continuously collects the national activity, which has recovered significantly from the SARS-CoV-2 pandemic impact in 2020. Success rate for 2021 remains high, with a low complication rate.

[Spanish catheter ablation registry. 21st official report of the Heart Rhythm Association of the Spanish Society of Cardiology (2021)]

Introduction and objectives

The results of the 2021 Spanish catheter ablation registry are presented.

Methods

Data collection was carried out retrospectively by filling in and sending a specific form by the participating centers.

Results

Data from 93 centers (65 public, 28 private) were analyzed. A total of 17941 ablation procedures were reported with a mean of 193 ± 133 clases per centre. Recovery of activity from SARS-CoV-2 pandemic lockdown has led to a notable increase in the number of procedures (+2772 procedures, +18%) despite a small decrease in participating centers (4 centers less than in 2020). Atrial fibrillation ablation continues to be the leading procedure, with 5848 procedures (32,6%). Together with ablation of the cavotricuspid isthmus (3766; 21%) and atrioventricular nodal reentrant tachycardia (3132; 17,5%) they constitute the 3 most frequently approached substrates. The total success rate reported (94%) is similar to previous years with a similar rate of complications (2%) and mortality (0.07). A total of 401 procedures were performed in pediatric patients (3,8%).

Conclusions

The Spanish catheter ablation registry systematically and continuously collects the national activity, which has recovered significantly from the SARS-CoV-2 pandemic impact in 2020. Success rate for 2021 remains high, with a low complication rate.

[Spanish Catheter Ablation Registry. 20th Official Report of the Heart Rhythm Association of the Spanish Society of Cardiology (2020)]

INTRODUCTION AND OBJECTIVES

This article reports the results of the 2020 Spanish Catheter Ablation Registry, a year marked by the SARS-CoV-2 pandemic.

METHODS

Data were collected retrospectively through completion and return of a specific form by the participating centers.

RESULTS

Data from 97 centers (67 public, 30 private) were analyzed. A total of 15 169 ablation procedures were reported with a mean of 155 ± 117 and a median [interquartile range] of 115 [62-227]. Because of the SARS-CoV-2 pandemic, both procedures and participating centers markedly decreased (-3380 procedures, -18%) and there were 5 centers less than in 2019. The most common procedure continued to be atrial fibrillation ablation (4513; 30%), well ahead of the remaining substrates, followed by ablation of the cavotricuspid isthmus (3188; 21%), and intranodal re-entry tachycardia (2808; 18%). Ablation of these 3 substrates continued to form the bulk of the procedures. The total success rate was slightly lower than in previous years (88%) with a similar complication rate (n = 309; 2%) and mortality (n = 7; 0.04%). A total of 243 procedures were performed in pediatric patients (1.6%).

CONCLUSIONS

The Spanish Catheter Ablation Registry systematically and continuously reflects the national trajectory, which, in 2020, was markedly affected by the SARS-CoV-2 pandemic. Although slightly lower than in previous years, the success rate remained high, with a low complication rate.Full English text available from:www.revespcardiol.org/en.

Spanish Catheter Ablation Registry. 20th Official Report of the Heart Rhythm Association of the Spanish Society of Cardiology (2020)

INTRODUCTION AND OBJECTIVES

This article reports the results of the 2020 Spanish Catheter Ablation Registry, a year marked by the SARS-CoV-2 pandemic.

METHODS

Data were collected retrospectively through completion and return of a specific form by the participating centers.

RESULTS

Data from 97 centers (67 public, 30 private) were analyzed. A total of 15 169 ablation procedures were reported with a mean of 155±117 and a median [interquartile range] of 115 [62-227]. Because of the SARS-CoV-2 pandemic, both procedures and participating centers markedly decreased (-3380 procedures,-18%) and there were 5 centers less than in 2019. The most common procedure continued to be atrial fibrillation ablation (4513; 30%), well ahead of the remaining substrates, followed by ablation of the cavotricuspid isthmus (3188; 21%), and intranodal re-entry tachycardia (2808; 18%). Ablation of these 3 substrates continued to form the bulk of the procedures. The total success rate was slightly lower than in previous years (88%) with a similar complication rate (n=309; 2%) and mortality (n=7; 0.04%). A total of 243 procedures were performed in pediatric patients (1.6%).

CONCLUSIONS

The Spanish Catheter Ablation Registry systematically and continuously reflects the national trajectory, which, in 2020, was markedly affected by the SARS-CoV-2 pandemic. Although slightly lower than in previous years, the success rate remained high, with a low complication rate.

[Spanish Catheter Ablation Registry. 19th Official Report of the Heart Rhythm Association of the Spanish Society of Cardiology (2019)]

INTRODUCTION AND OBJECTIVES

This report presents the findings of the 2019 Spanish Catheter Ablation Registry.

METHODS

Data collection was retrospective. A standardized questionnaire was filled by each of the participant centers.

RESULTS

Data sent by 102 centers were analyzed, with a total number of ablation procedures performed of 18 549 (the highest historically reported in this registry) for a mean of 181.9 ± 137.0 and a median of 144.5 procedures per center. The ablation targets most frequently treated were atrial fibrillation (n = 5164; 27.8%), cavotricuspid isthmus (n = 3925; 21.1%) and atrioventricular nodal reentrant tachycardia (n = 3768; 20.3%). A new peak is observed in the ablation of atrial fibrillation, increasing the distance from the other substrates. The overall success rate was again 91%. The rate of major complications was 1.9%, and the mortality rate was 0.03%. An electroanatomic mapping system was used in 44.5% of all procedures, with contact force-sensing irrigated catheters become the preferred for complex substrates, as atrial fibrillation (84.8%) or ventricular tachycardia (around 90%). 1.5% of the ablations were performed in pediatric patients.

CONCLUSIONS

The Spanish Catheter Ablation Registry enrolls systematically and uninterruptedly the ablation procedures performed in Spain, showing a progressive increasing in the number of ablations over the years with a high success rate and low percentages of complications.

Spanish Catheter Ablation Registry. 19th Official Report of the Heart Rhythm Association of the Spanish Society of Cardiology (2019)

INTRODUCTION AND OBJECTIVES

This report presents the findings of the 2019 Spanish Catheter Ablation Registry.

METHODS

Data collection was retrospective. A standardized questionnaire was filled by each of the participant centers.

RESULTS

Data sent by 102 centers were analyzed, with a total number of ablation procedures performed of 18549 (the highest historically reported in this registry) for a mean of 181.9±137.0 and a median of 144.5 procedures per center. The ablation targets most frequently treated were atrial fibrillation (n=5164; 27.8%), cavotricuspid isthmus (n=3925; 21.1%) and atrioventricular nodal reentrant tachycardia (n=3768; 20.3%). A new peak is observed in the ablation of atrial fibrillation, increasing the distance from the other substrates. The overall success rate was again 91%. The rate of major complications was 1.9%, and the mortality rate was 0.03%. An electroanatomic mapping system was used in 44.5% of all procedures, with contact force-sensing irrigated catheters become the preferred for complex substrates, as atrial fibrillation (84.8%) or ventricular tachycardia (around 90%). 1.5% of the ablations were performed in pediatric patients.

CONCLUSIONS

The Spanish Catheter Ablation Registry enrolls systematically and uninterruptedly the ablation procedures performed in Spain, showing a progressive increasing in the number of ablations over the years with a high success rate and low percentages of complications.

Spanish Catheter Ablation Registry. 18th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2018)

INTRODUCTION AND OBJECTIVES

This report presents the findings of the 2018 Spanish Catheter Ablation Registry.

METHODS

Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers.

RESULTS

Data sent by 100 centers were analyzed, with a total number of 16566 ablation procedures performed (the highest historically reported in this registry) for a mean of 165.5±127.9 and a median of 119 procedures per center. The ablation targets most frequently treated were atrial fibrillation (n=4234; 25.6%), atrioventricular nodal re-entrant tachycardia (n=3525; 21.3%) and cavotricuspid isthmus (n=3425; 20.7%). A new peak was observed in the ablation of atrial fibrillation, increasing the distance from the other substrates. The overall success rate was 91%. The rate of major complications was 2.2%, and the mortality rate was 0.04%. A total of 2.1% of the ablations were performed in pediatric patients.

CONCLUSIONS

The Spanish Catheter Ablation Registry enrolls systematically and continuously enrolls the ablation procedures performed in Spain, showing a progressive increasing in the number of ablations over the years, with a high success rate and low percentage of complications.

Spanish Catheter Ablation Registry. 17th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2017)

INTRODUCTION AND OBJECTIVES

This report describes the findings of the 2017 Spanish Catheter Ablation Registry.

METHODS

Data collection was retrospective. A standardized questionnaire was completed by each of the participating centers.

RESULTS

A total of 15 284 ablation procedures were performed by 98 institutions (the highest number of ablations and institutions historically reported in this registry), with a mean of 156±126 and a median of 136 procedures per center. For the first time, the most frequently treated ablation target was atrial fibrillation (n=3457; 22.6%), followed by cavotricuspid isthmus (n=3449; 22.5%) and atrioventricular nodal re-entrant tachycardia (n=3429; 22.4%). The overall success rate was 87%. The rate of major complications was 2.6%, and the mortality rate was 0.09%. The percentage of procedures performed without fluoroscopic support increased to 6% of all ablations, and 2.3% of all ablations were performed in pediatric patients.

CONCLUSIONS

The Spanish Ablation Catheter Registry systematically and uninterruptedly collects data on the ablation procedures performed in Spain, revealing that both the number of ablations and the number of centers performing them has progressively increased, while maintaining a high success rate and a low percentage of complications.

Spanish Catheter Ablation Registry. 16th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2016)

INTRODUCTION AND OBJECTIVES

This report describes the findings of the 2016 Spanish Catheter Ablation Registry.

METHODS

Data were retrospectively collected by means of a standardized questionnaire completed by each of the participating centers.

RESULTS

Data were collected from 83 centers. A total of 13 482 ablation procedures were performed (the highest historically reported in this registry), with a mean of 162.4 ± 116 and a median of 136 procedures per center. The most frequently treated ablation targets were atrioventricular nodal re-entrant tachycardia (n = 3058; 22.7%), atrial fibrillation (n = 2953; 21.9%), and cavotricuspid isthmus (n = 2892; 21.4%). There was a peak in ablation procedures for atrial fibrillation, which, for the first time in this registry, became the second most treated substrate. After exclusion of atrial fibrillation and ventricular tachycardia with underlying heart disease, the overall success rate was 86%. The rate of major complications was 2.3%, and the mortality rate was 0.05%. In all, 2.7% of the ablations were performed in pediatric patients.

CONCLUSIONS

The Spanish Catheter Ablation Registry systematically and uninterruptedly records the ablation procedures performed in Spain, showing a progressive rise in the number of ablations performed, with a high success rate and a low percentage of complications.

Spanish Catheter Ablation Registry. 15th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2015)

INTRODUCTION AND OBJECTIVES

This report presents the findings of the 2015 Spanish Catheter Ablation Registry.

METHODS

For data collection, each center was allowed to choose freely between 2 systems: retrospective, requiring the completion of a standardized questionnaire, and prospective, involving reporting to a central database.

RESULTS

Data were collected from 82 centers. A total of 12 863 ablation procedures were performed, for a mean of 157±119 and a median of 138 procedures per center. The ablation target most frequently treated was cavotricuspid isthmus (n=2992 [23.2%]), followed by atrioventricular nodal reentrant tachycardia (n=2966 [23%]) and atrial fibrillation (n=2640 [20.5%]). There were fewer ablation procedures for atrial tachycardia, idiopathic ventricular tachycardia and accessory pathways, while those for ventricular tachycardia in ischemic cardiomyopathy remained steady. The overall success rate, excluding atrial fibrillation and ventricular tachycardia in cardiomyopathy, was 87.5%, the rate of major complications was 2%, and the mortality rate was 0.08%.

CONCLUSIONS

The 2015 registry is the first to show a slight reduction in the number of centers sending in their results and in the total number of ablation procedures performed. The most frequently treated substrate was the cavotricuspid isthmus. There was also a slight decrease in the success rate. The complications and mortality rates remained low.

Care Indicators in Patients With Atrial Fibrillation: Assessment of Sex Differences and Management of Clinical Problems

INTRODUCTION AND OBJECTIVES

To assess sex differences and the management of clinical problems in patients with atrial fibrillation through the use of care indicators.

METHODS

Over a 5-month period, the study included all consecutive patients attended in the cardiology outpatient clinics of 2 tertiary hospitals with an atrial fibrillation episode or a clinical process due to atrial fibrillation.

RESULTS

A total of 533 patients were included (56.5% women; mean age, 70.5 ± 12.2 years), of whom 24.3% were younger than 65 years. Women had significantly more clinical problems and a higher stroke risk: CHADS2 (congestive heart failure, hypertension, age, diabetes, stroke [doubled]) (1.8 ± 1.2 vs 1.5 ± 1.1; P = .001) and CHA2DS2-VASc (congestive heart failure, hypertension, age ≥ 75 [doubled], diabetes, stroke [doubled]-vascular disease and sex category [female]) (3.7 ± 1.4 vs 2.2 ± 1.4; P = .0001). Referrals to the cardiology department were appropriate in 94% of the patients, the referral source was primary care or other hospital services in 53.8%, and echocardiography was performed or recommended in 93.4%. Treatment (antiarrhythmics and anticoagulants) was administered according to guideline recommendations. In the previous 3 months, the Rosendaal index was 48.4 ± 37.4.

CONCLUSIONS

One in every 4 patients seeking care for problems associated with atrial fibrillation are young; women have more clinical problems and seek care more frequently than men. Patients are correctly referred to the cardiology department and most are not referred from the emergency department. Echocardiography and antiarrhythmic and anticoagulant therapy were provided according to the recommendations of clinical practice guidelines. Vitamin K antagonists for anticoagulation therapy are underused.

Electrical Isolation of Pulmonary Veins Using Laser Catheter in the Treatment of Paroxysmal and Persistent Atrial Fibrillation. One-year Results

INTRODUCTION AND OBJECTIVES

A new laser balloon that allows visualization of atrial tissue has recently been introduced for pulmonary vein electrical isolation. The aim of this study was to evaluate the mid-term safety and efficacy of this catheter in the treatment of atrial fibrillation.

METHODS

Laser balloon ablation was performed in 71 patients with paroxysmal (80%) or persistent (20%) atrial fibrillation. Arrhythmia recurrence was defined as any episode lasting longer than 30 seconds. During follow-up, regular visits were performed every 3 months with 24- to 48-hour Holter tests.

RESULTS

Isolation was possible in 275 of 278 (99%) of pulmonary veins. Mean procedure and fluoroscopy times were 154 ± 25 and 34 ± 15minutes, respectively. A total of 89% of veins were isolated during the first attempt. The most common complication was phrenic nerve paralysis (5.6%), which appeared in only the first 18 cases. A total of 59 patients received follow-up for a mean of 420 ± 193 days, with a rate of arrhythmia recurrence of 12% and 30%, respectively, in paroxysmal and persistent atrial fibrillation (P = .155).

CONCLUSIONS

The laser balloon is a safe and effective system for pulmonary vein electrical isolation. Its advantages include the capacity to adapt to pulmonary vein anatomy using a single catheter, the efficacy with which pulmonary vein electrical isolation is achieved, and the favorable mid-term clinical progress, even for patients with persistent atrial fibrillation.

Myocardial injury during radiofrequency and cryoablation of typical atrial flutter

PURPOSE

Cardiac enzyme elevation after radiofrequency (RF) catheter ablation of atrial flutter (AFL) is common. Some studies found that cryoablation (CRYO) of AFL, compared to RF, is associated with higher levels of troponin, a finding that may indicate CRYO causes a greater amount of myocardial injury than RF. However, other investigations found no significant differences between troponin levels after CRYO versus RF. We have in a randomized study compared the post-procedural troponin I levels in RF and CRYO and the possible relation to procedural outcome and complications.

METHODS

We randomized 153 patients with cavotricuspid isthmus (CTI)-dependent AFL to CRYO or RF (78 CRYO; 75 RF). RF was performed with a 3.5-mm open-irrigated-tip catheter, and CRYO was performed with an 8-mm-tip catheter. Troponin I levels were measured before and 6 h after ablation.

RESULTS

Acute procedural success was achieved in 71/75 patients in the RF and in 72/78 patients in the CRYO. Troponin I levels were significantly elevated in both groups (baseline 0.012, 6th hour 0.35 ng/ml; p < 0.001). Troponin I levels were similar for RF and CRYO. Troponin I levels were higher in patients with acute failure compared to patients with acute success (0.48 ± 0.4 and 0.34 ± 0.16 ng/ml, p = 0.029); however, there was no difference between patients with or without late recurrence. There were no major complications in any group.

CONCLUSION

RF and CRYO for CTI-dependent AFL resulted in similar amounts of procedural myocardial injury. Troponin I levels had no prognostic value for late recurrence of AFL and there were no complications related to high troponin I levels.

Spanish Catheter Ablation Registry. 14th Official Report of the Spanish Society of Cardiology Working Group on Electrophysiology and Arrhythmias (2014)

INTRODUCTION AND OBJECTIVES

This report presents the findings of the 2014 Spanish Catheter Ablation Registry.

METHODS

For data collection, each center was allowed to choose freely between 2 systems: retrospective, requiring the completion of a standardized questionnaire, and prospective, involving reporting to a central database.

RESULTS

Data were collected from 85 centers. A total of 12 871 ablation procedures were performed, for a mean of 149.5±103 procedures per center. The ablation targets most frequently treated were atrioventricular nodal reentrant tachycardia (n=3026; 23.5%), cavotricuspid isthmus (n=2833; 22.0%), and atrial fibrillation (n=2498; 19.4%). The number of ablation procedures for ventricular arrhythmias was similar to that of 2013, but there was a slight increase in the treatment of all the ventricular substrates, especially those associated with idiopathic ventricular tachycardia and scarring following myocardial infarction. The overall success rate was 95%, the rate of major complications was 1.3%, and the mortality rate was 0.02%.

CONCLUSIONS

The 2014 registry shows that the number of ablation procedures performed continued its upward trend and that, overall, the success rate was high and the number of complications low. Ablation of complex conditions continued to increase.

Performance of the SA-VA Difference to Differentiate Atrioventricular Nodal Reentrant Tachycardia from Orthodromic Reentrant Tachycardia in a Large Cohort of Consecutive Patients

BACKGROUND

The stimulus-atrial (SA) interval minus ventriculoatrial (VA) interval (SA-VA) difference represents a simple diagnostic maneuver to distinguish between atrioventricular nodal reentrant tachycardia (AVNRT) and orthodromic reentrant tachycardia (ORT) during electrophysiology study. However, its usefulness has largely been studied in selected patient subgroups. The purpose of this study was to evaluate the performance of the SA-VA difference against commonly used diagnostic maneuvers in a large cohort of consecutive patients.

METHODS

Consecutive patients with inducible supraventricular tachycardia and successful entrainment through pacing trains from right ventricular apex during an electrophysiological study were included. Atrial tachycardias were excluded. The following intervals were calculated for each patient: SA-VA difference, His potential, and atrial electrogram during entrainment minus His potential and atrial electrogram during tachycardia, and the corrected return cycle.

RESULTS

A total of 456 patients fulfilled the inclusion criteria, of which electrophysiological study revealed 265 typical AVNRT, 38 atypical AVNRT, and 54 and 108 ORT through a septal and free-wall accessory pathway, respectively. An SA-VA difference >99 ms identified AVNRT in all patients with sensitivity, specificity, and positive and negative predictive values of 97.7%, 96.9%, 98.3%, and 95.7%, respectively.

CONCLUSIONS

This study confirms the high ability to distinguish AVNRT from ORT using the SA-VA difference, not only in selected patient subgroups, but as whole when a cut-off of >99 ms is used.

Number of Beats in the Transition Zone With Fixed SA Interval during Right Ventricular Overdrive Pacing Determines Accessory Pathway Location in Orthodromic Reentrant Tachycardia

BACKGROUND

Ventricular overdrive pacing (VOP) produces reset during the transition zone (TZ) of QRS fusion in orthodromic reentrant tachycardia (ORT) and after the TZ in atrioventricular nodal reentrant tachycardia (AVNRT), and this represents a simple diagnostic maneuver to differentiate the two tachycardia mechanisms.

OBJECTIVE

The purpose of this study was to determine whether the number of beats with reset in the TZ predicts accessory pathway (AP) location in ORT.

METHODS

We retrospectively reviewed 57 patients with ORT (21 left-sided AP, 20 septal AP, and 16 right-sided AP) and 20 patients with AVNRT (19 typical AVNRT and one atypical AVNRT) who underwent VOP from the right ventricular apex. We analyzed the number of beats with reset during or after the TZ, demonstrated by fixed ventricular stimulus-atrial (SA) interval during VOP.

RESULTS

The overall mean tachycardia cycle length [CL] minus VOP CL was 22.6 ± 7.5 ms with no statistical difference between the groups (P = 0.480). The mean number of beats in the TZ with fixed SA interval was 2.5 ± 1.4 for the whole ORT group, 1.1 ± 0.4 for left-sided AP (range 1-2), 2.8  ±  0.9 for septal AP (range 1-5), and 4.0 ± 0.9 for right-sided AP (range 3-6) (P < 0.001). Using a cutoff >2 beats distinguished right- versus left-sided AP in all cases.

CONCLUSION

Assessing the number of beats in the TZ with fixed SA interval during VOP helps to determine AP location in ORT and adds valuable information to an established simple diagnostic pacing maneuver, especially when a two-catheter simplified approach is employed.