Nonautomatic focal atrial tachycardia: characterization and ablation of a poorly understood arrhythmia in 38 patients

Early and Late Postoperative Tachyarrhythmias in Children and Young Adults Undergoing Congenital Heart Disease Surgery

The population of patients with congenital heart disease is constantly growing with an increasing number of individuals reaching adulthood. A significant proportion of these children and young adults will suffer from tachyarrhythmias due to the abnormal anatomy, the hemodynamic burden, or as a sequela of surgical treatment. Depending on the underlying mechanism, arrhythmias may arise in the early postoperative period (hours to days after surgery) or in the late postoperative period (usually years after surgery). A good understanding of the electrophysiological characteristics and pathophysiological mechanisms is therefore crucial to guide the therapeutic approach. Here, we synthesize the current state of knowledge on epidemiological features, risk factors, pathophysiological insights, electrophysiological features, and therapy regarding tachyarrhythmias in children and young adults undergoing reparative surgery for congenital heart disease. The evolution and latest data on treatment options, including pharmacological therapy, ablation procedures, device therapy decision, and thromboprophylaxis, are summarized. Finally, throughout this comprehensive review, knowledge gaps and areas for future research are also identified.

Sex differences on outcomes of catheter ablation of ventricular tachycardia in patients with structural heart disease: A real-world systematic review and meta-analysis

Background

Sex differences have diversely affected cardiac diseases. Little is known whether these differences impact outcomes of catheter ablation of ventricular tachycardia (VT).

Objectives

To assess the impact of sex differences on outcomes of catheter ablation of VT.

Methods

Databases were searched from inception through December 2021. Effect estimates from individual studies were extracted and combined using the random-effects, generic inverse variance method of DerSimonian and Laird. The outcomes of interest included VT recurrence rates, all-cause mortality, and composite outcomes of mortality, left ventricular assistant device use, and heart transplantation following VT ablation.

Results

Our analysis included 22 observational studies. There were 10,206 patients, of which 12.8% were women. We found no statistical difference between sexes for VT recurrence rate (pooled hazard ratio [HR] 1.04, P = .57, I ² = 14.9%). Similarly, there was statistical difference in neither all-cause mortality nor composite outcomes (pooled HR 0.93, P = .75, I ² = 59.1% and pooled HR 0.9, P = .33, I ² = 0%, respectively). There was a trend toward an increase in women undergoing VT ablation in the recent registries (P = .071).

Conclusion

Our contemporary analysis suggests that sex may have no impact on clinical outcomes of catheter ablation of VT in patients with structural heart disease, though women are the underrepresented. However, recent VT ablation registries have involved more women in their studies. Future studies with a higher proportion of women are encouraged to verify the current perception.

Arrhythmias in Female Patients: Incidence, Presentation and Management

There is a growing appreciation for differences in epidemiology, treatment, and outcomes of cardiovascular conditions by sex. Historically, cardiovascular clinical trials have under-represented females, but findings have nonetheless been applied to clinical care in a sex-agnostic manner. Thus, much of the collective knowledge about sex-specific cardiovascular outcomes result from post hoc and secondary analyses. In some cases, these investigations have revealed important sex-based differences with implications for optimizing care for female patients with arrhythmias. This review explores the available evidence related to cardiac arrhythmia care among females, with emphasis on areas in which important sex differences are known or suggested. Considerations related to improving female enrollment in clinical trials as a way to establish more robust clinical evidence for the treatment of females are discussed. Areas of remaining evidence gaps are provided, and recommendations for areas of future research and specific action items are suggested. The overarching goal is to improve appreciation for sex-based differences in cardiac arrhythmia care as 1 component of a comprehensive plan to optimize arrhythmia care for all patients.

Single-center experience of ultra-high-density mapping guided catheter ablation of focal atrial tachycardia

Introduction

Catheter ablation is the treatment of choice for recurrent focal atrial tachycardia (FAT) as medical therapy is limited. Routinely, a three‐dimensional mapping system is used. Whether or not optimized signal detection does improve ablation success rates has not yet been investigated. This retrospective cohort study compared ablation procedures using an ultra‐high‐density mapping system (UHDM, Rhythmia, Boston Scientific) with improved signal detection and automatic annotation with procedures using a conventional electroanatomic mapping system (CEAM, Biosense Webster, CARTO).

Methods

All patients undergoing ablation for FAT using UHDM or CEAM from April 2015 to August 2018 were included. Endpoints comprised procedural parameters, acute success as well as freedom from arrhythmia 12 months after ablation.

Results

A total of 70 patients underwent ablation (48 with UHDM, 22 with CEAM). No significant differences were noted for parameters like procedural and radiation duration, area dose, and RF applications. Acute success was significantly higher in the UHDM cohort (89.6% vs. 68.2%, p = .03). Nevertheless, arrhythmia freedom 12 months after ablation was almost identical (56.8% vs. 60%, p = .87), as more patients with acute success of ablation presented with a relapse during follow‐up (35.0 vs. 7.7%, p = .05).

Conclusion

Acute success rate of FAT ablation might be improved by UHDM, without an adverse effect on procedural parameters. Nevertheless, further research is needed to understand the underlying mechanism for increased recurrence rates after acute successful ablation.

Gender associated disparities in atrioventricular nodal reentrant tachycardia: A review article

Atrioventricular nodal reentrant tachycardia (AVNRT) is the most common sustained supraventricular arrhythmias. An understanding of gender-related differences in AVNRT epidemiology, diagnosis, treatment, outcome, and complications can help guide a more effective diagnosis and treatment of the condition. The study aimed to perform a review of the available literature regarding all aspects of gender-related differences of AVNRT. We focused on all aspects of gender-related differences regarding AVNRT between men and women. A literature search was performed using Google Scholar, PubMed, Springer, Ovid, and Science Direct. Many investigations have demonstrated that the prevalence of AVNRT exhibited a twofold women-to-men predominance. The potential mechanism behind this difference due to sex hormones and autonomic tone. Despite being more common in women, there is a delay in offering and performing the first-line therapy (catheter ablation) compared to men. There were no significant gender-related discrepancies in patients who underwent ablation therapy for AVNRT, regarding the acute success rate of the procedure, long-term success rate, and recurrence of AVNRT. AVNRT is more common in women due to physiological factors such as sex hormones and autonomic tone. Catheter ablation is equally safe and efficacious in men and women; however, the time between the onset of symptoms and ablation is significantly prolonged in women. It is important for the medical community to be aware of this discrepancy and to strive to eliminate such disparities that are not related to patients' choices.

Focal atrial tachycardia-the localization differences between men and women: A study of 487 consecutive patients

Objective:

The preferential sites for focal atrial tachycardia (FAT) are mainly in the right atrium in both sexes. However, a limited number of studies have indicated that sex differences in the localization of FAT. This study investigated possible sex differences in the distribution of FAT in a large cohort of patients referred for ablation.

Methods:

From 2004 to 2019, 487 patients (298 women) were referred to our institution for ablation of FAT. A standard electrophysiological study was conducted, and isoproterenol or atropine was given when needed. Conventional catheter mapping, electroanatomic contact mapping, and noncontact mapping were used to assess the origin of ectopic atrial tachycardia.

Results:

Overall, 451 foci were successfully ablated in 436 patients (90%). Although the foci located along the crista terminalis were more common in women than in men (42% vs. 29%; p=0.023), the opposite were found in the foci located along the tricuspid annulus (5% vs. 11%; p=0.032) and the right atrial appendage (RAA) (1% vs. 3%; p=0.032). Other locations were similarly distributed in men and women. In addition, the presence of persistent FAT was more frequent in men than in women (22% vs. 5%; p<0.001). Finally, the difference in the induction pattern of FAT was also remarkable between sexes.

Conclusion:

The distribution of FAT in women and men is different. In addition, persistent FAT seems more often in men than in women. The different distribution, persistency, and induction pattern of FAT should be considered in the successful management of this type of tachycardia. (Anatol J Cardiol 2020; 24: 405-9)

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.

Arrhythmia-Induced Cardiomyopathies: Mechanisms, Recognition, and Management

Arrhythmia-induced cardiomyopathy (AIC) is a potentially reversible condition in which left ventricular dysfunction is induced or mediated by atrial or ventricular arrhythmias. Cellular and extracellular changes in response to the culprit arrhythmia have been identified, but specific pathophysiological mechanisms remain unclear. Early recognition of AIC and prompt treatment of the culprit arrhythmia using pharmacological or ablative techniques result in symptom resolution and recovery of ventricular function. Although cardiomyopathy in response to an arrhythmia may take months to years to develop, recurrent arrhythmia can result in rapid decline in ventricular function with development of heart failure, suggesting residual ultrastructural abnormalities. Reports of sudden death in patients with normalized left ventricular ejection fraction cast doubt on the complete reversibility of this condition. Several aspects of AIC, including specific pathophysiological mechanisms, predisposing factors, optimal therapeutic strategies to prevent ultrastructural changes, and long-term risk of sudden death remain unresolved and need further research.

Radiofrequency ablation of nonautomatic focal atrial tachycardia in children with structurally normal hearts

INTRODUCTION

The majority of children presenting with paroxysmal supraventricular tachycardia (SVT) have either accessory-pathway-mediated tachycardia or AV node reentry tachycardia. The purpose of this study is to report an unusual mechanism of SVT found in children with structurally normal hearts.

METHODS AND RESULTS

Records of all patients undergoing an electrophysiology study (EPS) at our institution between 2000 and 2004 were reviewed to identify those with nonautomatic focal atrial tachycardia (NAFAT). Five patients (three males) with an average age of 13.8 years (median 15 years, range 7-18 years) were identified. All presented with paroxysmal palpitations. They all had structurally normal hearts. At EPS, SVT was reproducibly induced with programmed atrial stimulation (single, double, or triple extrastimuli) in all patients. The average cycle length was 276 +/- 9 ms. Adenosine terminated SVT in 2. A 3-D electro-anatomical system mapping was used in all cases. The right atrium (RA) was mapped in all and the left in two. Foci were mapped to the posterior high RA, lateral RA, lower mid RA septum, inferior to the sinus node, and in the right and left posteroseptal areas. Average number of radiofrequency lesions placed was 8.6 +/- 5. The success rate was 80%; there was one late recurrence. No procedural complications were observed.

CONCLUSIONS

NAFAT is a rare form of tachycardia that should be considered in the differential diagnosis of children presenting with SVT. It is amenable to mapping and radiofrequency ablation.

Fragmented, Long-Duration, Low-Amplitude Electrograms Characterize the Origin of Focal Atrial Tachycardia

BACKGROUND

Focal atrial tachycardias (FAT) originate from areas with poor cell-to-cell coupling. Due to cellular uncoupling extracellular potentials become fractionated. The degree of fragmentation may be used to identify the site of origin of FAT prior to catheter ablation. We studied electrical fragmentation in relation to the distance to the site of earliest activity during FAT.

METHODS

Three-dimensional (3-D) electroanatomical activation/voltage maps obtained from patients (n = 15: 6 male, age 40 +/- 14 (19-72) years) referred for catheter ablation of FAT were analyzed. Bipolar atrial potentials (BP) were categorized according to the number of deflections. The peak-to-peak amplitude and the time interval between the first and last deflection (fractionation duration) of each BP were measured.

RESULTS

Eighteen different atrial tachycardias (AT) (CL 346 +/- 109 [190-550]) msec were analyzed. The incidence of single potentials ranged from 30 to 81 (59 +/- 16)%. The occurrence of double and fractionated potentials < or = 2 cm of the site of earliest activity ("focal area") was higher compared to the remainder of the atria (67 +/- 22% vs 34 +/- 14%, P < 0.001). Focal area potentials were characterized by a longer duration (49 +/- 22 msec vs 34 +/- 17 msec, P < 0.001) and a lower peak-to-peak amplitude (0.51 +/- 0.43 [0.12-1.7] mV vs 0.94 +/- 0.69 [0.22-2.58] mV, P = 0.03). Fractionation was not associated with FAT cycle length (r =-0.26, P = 0.29) or left atrial diameter (r = 0.47, P = 0.30).

CONCLUSION

Significant differences in fractionation, fractionation duration, and peak-to-peak-amplitude of atrial potentials between the focal area and the remainder of the atria exist. Fractionation and voltage mapping can be used, besides activation mapping, to identify the site of origin of FAT during catheter ablation.

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.

Ablation of Nonautomatic Focal Atrial Tachycardia in Children and Adults with Congenital Heart Disease

INTRODUCTION

Nonautomatic focal atrial tachycardia (NAFAT) has been characterized in adults with structurally normal hearts. This article characterizes NAFAT in a population of patients with complex congenital heart disease.

METHODS AND RESULTS

Electrophysiologic and electroanatomic mapping data and acute outcomes were reviewed in patients undergoing mapping and ablative procedures for atrial tachycardia at Children's Hospital, Boston, between January 1999 and December 2003. Twenty-two NAFAT foci were identified in 17 patients out of 216 patients studied. Fourteen of these 17 patients had congenital heart disease. The average age of the patients with a NAFAT mechanism was 27 years and there was no gender predilection. The presumptive diagnosis based on clinical grounds and surface ECG assessment in 11 of 17 patients with NAFAT was atrial flutter. None of the 17 patients were suspected of having a NAFAT mechanism by noninvasive assessment. Four of the 10 patients had both NAFAT and macroreentrant atrial tachycardias. NAFAT cycle lengths varied widely (200-680 ms) between patients. Sixteen of the 22 NAFAT foci were mapped to the anatomic right atrium (RA). Acute ablative success was achieved in 17 out of 22 foci (77%).

CONCLUSION

NAFAT is relatively uncommon in a pediatric tertiary care setting, and in that setting occurs most often in adults with congenital heart disease. NAFAT is indistinguishable from other forms of atrial tachycardia by noninvasive means and can mimic other forms of atrial tachycardia on electrocardiogram. The foci were predominantly found in the RA and were, in most cases, acutely amenable to catheter ablation therapy.