Electrocardiographic and Electrophysiological Characteristics of Atrial Tachycardia With Early Activation Close to the His-Bundle

Distribution Variance of Focal Atrial Tachycardia Foci and Long-Term Outcomes After Ablation: Experience From Two Chinese Centers

INTRODUCTION

The distribution of the origin of focal atrial tachycardia (FAT) in patients with different ages have not been clearly elucidated. We aimed to evaluate age differences in foci and factors influencing recurrence after radiofrequency catheter ablation in adult and juvenile patients with FAT.

METHODS AND RESULTS

A total of 323 consecutive FAT patients who underwent electrophysiological study and radiofrequency catheter ablation between January 2011 and March 2023 were selected for this study. We divided the patients into three groups according to the age of FAT onset: juvenile (< 18 years), young adult (≥ 18 and < 45 years), and middle-aged and old adult (≥ 45 years). Juvenile had a higher proportion of FAT originating from the left atrial appendage, the right atrial appendage, and the free or posterior wall of the right atrium. FAT in middle-aged and old adult patients was more likely to originate from the crista terminalis, tricuspid annulus, non-coronary cusp, and para-His. Young adults had a higher proportion of FAT originating from the superior vena cava and pulmonary veins. After a mean follow-up of 47.2 months, FAT recurred in 57 patients. Multivariate Cox regression analysis suggested that multifocal ablation (HR: 3.055, 95% CI: 1.476-6.323) and NT-proBNP (per standard deviation, HR: 1.367, 95% CI: 1.157-1.614) were independently associated with arrhythmia recurrence after ablation.

CONCLUSION

Significant age differences were observed in the distribution of FAT foci. Multifocal AT and elevated NT-proBNP independently predicted FAT recurrence after ablation.

Intracardiac Echocardiography to Guide the Ablation of Parahisian Arrhythmias

Arrhythmias from the perinodal region have been described for accessory pathways (APs), atrial tachycardias (AT), premature ventricular complexes (PVCs), and ventricular tachycardia (VT). The parahisian (PH) region encompasses anatomic structures that include the atrioventricular (AV) node and His-Bundle (HB). These locations are at high-risk for inducing AV block during catheter ablation in the electrophysiology laboratory. PH arrhythmias were initially defined as having sites of origin within 10 mm of the largest HB potential (>0.1 mV) recording site, but more recent definitions have included any site that has an HB potential at the ablation site. Intracardiac echocardiography (ICE) use offers real-time visualization of the catheter tip-to-tissue contact and can monitor for acute complications during atrial and ventricular procedures. ICE also enables a broad appreciation of real-time cardiac structures, which is invaluable in navigating the complex anatomy of the PH region.

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

BACKGROUND

Atrial tachycardia (AT) ablation with earliest activation site close to the His-Bundle is a challenge due to the risk of complete AV block by its proximity to His-Purkinje system (HPS). An alternative to minimize this risk is to position the catheter on the non-coronary cusp (NCC), which is anatomically contiguous to the para-Hisian region.

OBJECTIVES

The aim of this study was to perform a literature review and evaluate the electrophysiological characteristics, safety, and success rate of catheter-based radiofrequency (RF) delivery in the NCC for the treatment of para-Hisian AT in a case series.

METHODS

This study performed a retrospective evaluation of ten patients (Age: 36±10 y-o) who had been referred for SVT ablation and presented a diagnosis of para-Hisian focal AT confirmed by classical electrophysiological maneuvers. For statistical analysis, a p-value of <0.05 was considered statistically significant.

RESULTS

The earliest atrial activation at the His position was 28±12ms from the P wave and at the NCC was 3±2ms earlier than His position, without evidence of His potential in all patients. RF was applied on the NCC (4-mm-tip catheter; 30W, 55ºC), and the tachycardia was interrupted in 5±3s with no increase in the PR interval or evidence of junctional rhythm. Electrophysiological tests did not reinduce tachycardia in 9/10 of patients. There were no complications in all procedures. During the 30 ± 12 months follow-up, no patient presented tachycardia recurrence.

CONCLUSION

The percutaneous treatment of para-Hisian AT through the NCC is an effective and safe strategy, which represents an interesting option for the treatment of this complex arrhythmia. (Arq Bras Cardiol. 2021; 116(1):119-126).

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.