Case Report: Application of Thoracoscopic Clamp Radiofrequency Ablation on Atrial Tachycardia Originating From Right Atrial Appendage After Catheter Ablation Failure

Atrial tachycardia originating from the right atrial appendage has a higher probability of failure of catheter ablation. Here we report a case of a 13-year-old boy with incessant tachycardia, complicated by heart enlargement, and heart failure. Electrophysiological examination showed that atrial tachycardia (AT) originated from the apex of the right atrial appendage, and endocardial catheter ablation was ineffective. After thoracoscopic approach, the right atrial appendage was successfully ablated with bipolar radiofrequency ablation forceps, atrial tachycardia was terminated and sinus rhythm was restored. Within 3 months since the patient was discharged from the hospital, no arrhythmia occurred and the heart structure returned to normal. Thus, thoracoscopic clamp radiofrequency ablation may be a reasonable choice for young patients with atrial tachycardia originated from the right atrial appendage when transendocardial ablation is not effective.

Incessant Atrial Tachycardia as First Presentation of Cardiac Angiosarcoma

Primary cardiac angiosarcomas are rare malignant tumors with a very poor prognosis. We present a case of a 48-year-old man with no previous cardiac history who developed an incessant focal atrial tachycardia complicated by tachycardia-mediated cardiomyopathy as a consequence of cardiac angiosarcoma. (Level of Difficulty: Beginner.)

Atrial arrhythmia related outcomes in critically ill COVID-19 patients

Rationale

Coronavirus disease 2019 (COVID‐19) is associated with many clinical manifestations including respiratory failure and cardiovascular compromise.

Objectives

We examine outcomes in critically ill individuals with COVID‐19 who develop atrial tachyarrhythmias.

Methods

We collected data from electrocardiograms and the electronic medical record of COVID‐19 positive (COVID⁺) and negative (COVID⁻) individuals admitted to our medical intensive care unit between February 29 and June 28, 2020. We compared clinical and demographic characteristics, new onset atrial tachyarrhythmia, hemodynamic compromise following atrial tachyarrhythmia, and in‐hospital mortality in COVID⁺ versus COVID⁻. Hemodynamic compromise was defined as having a new or increased vasopressor requirement or the need for direct current cardioversion for hemodynamic instability within 1 hour of atrial tachyarrhythmia onset.

Results

Of 300 individuals included, 200 were COVID⁺ and 100 were COVID⁻. Mean age was 60 ± 16 years, 180 (60%) were males, and 170 (57%) were African American. New onset atrial tachyarrhythmia occurred in 16% of COVID⁺ and 19% of COVID⁻ individuals (P = .51). When compared to COVID⁻ participants without atrial tachyarrhythmia, COVID⁺ individuals with new onset atrial tachyarrhythmia had higher mortality after multivariable adjustment (OR 5.0, 95% CI 1.9–13.5). New onset atrial tachyarrhythmia was followed by hemodynamic compromise in 18 COVID⁺ but no COVID⁻ participants (P = .0001). COVID⁺ individuals with hemodynamic compromise after atrial tachyarrhythmia required increased ventilatory support at the time of atrial tachyarrhythmia onset.

Conclusions

Atrial tachyarrhythmia is associated with increased mortality in critically ill individuals with COVID‐19, especially those mechanically ventilated. Recognition of this could assist with clinical care for individuals with COVID‐19.

Evaluation of Directed Graph-Mapping in Complex Atrial Tachycardias

OBJECTIVES

Directed graph-mapping (DGM) is a novel operator-independent automatic tool that can be applied to the identification of the atrial tachycardia (AT) mechanism. In the present study, for the first time, DGM was applied in complex AT cases, and diagnostic accuracy was evaluated.

BACKGROUND

Catheter ablation of ATs still represents a challenge, as the identification of the correct mechanism can be difficult. New algorithms for high-density activation mapping (HDAM) render an easier acquisition of more detailed maps; however, understanding of the mechanism and, thus, identification of the ablation targets, especially in complex cases, remains strongly operator-dependent.

METHODS

HDAMs acquired with the latest algorithm (COHERENT version 7, Biosense Webster, Irvine, California) were interpreted offline by 4 expert electrophysiologists, and the acquired electrode recordings with corresponding local activation times (LATs) were analyzed by DGM (also offline). Entrainment maneuvers (EM) were performed to understand the correct mechanism, which was then confirmed by successful ablation (13 cases were centrifugal, 10 cases were localized re-entry, 22 cases were macro-re-entry, and 6 were double-loops). In total, 51 ATs were retrospectively analyzed. We compared the diagnoses made by DGM were compared with those of the experts and with additional EM results.

RESULTS

In total, 51 ATs were retrospectively analyzed. Experts diagnosed the correct AT mechanism and location in 33 cases versus DGM in 38 cases. Diagnostic accuracy varied according to different AT mechanisms. The 13 centrifugal activation patterns were always correctly identified by both methods; 2 of 10 localized reentries were identified by the experts, whereas DGM diagnosed 7 of 10. For the macro-re-entries, 12 of 22 were correctly identified using HDAM versus 13 of 22 for DGM. Finally, 6 of 6 double-loops were correctly identified by the experts, versus 5 of 6 for DGM.

CONCLUSIONS

Even in complex cases, DGM provides an automatic, fast, and operator-independent tool to identify the AT mechanism and location and could be a valuable addition to current mapping technologies.

The mechanisms of left septal and anterior wall reentrant atrial tachycardias analyzed with ultrahigh resolution mapping: The role of functional block in the circuit

BACKGROUND

Low voltage areas (LVAs) are most commonly observed on the left atrial (LA) septal/anterior wall.

OBJECTIVE

We explored the mechanisms of LA septal/anterior wall reentrant tachycardias (LASARTs) using ultrahigh resolution mapping.

METHODS

This study included seven consecutive LASARTs in six patients (75 [62.2-82.8] years, 4 women) who underwent atrial tachycardia (AT) mapping and ablation using Rhythmia systems.

RESULTS

The AT cycle length was 266 (239-321) ms. During ATs, 11.0 (9.0-12.9) cm² of LVAs were identified in all, and 0.8 (0.7-1.7) cm² of dense scar was identified in four patients. Five ATs rotated around dense scar, while two rotated around functional linear block, which was confirmed during atrial pacing after AT termination. The AT circuit length was 8.7 ± 2.1 cm with a conduction velocity of 30.4 ± 3.7 cm/s. A median of 3.0 (2.0-4.0) slow conduction areas per circuit were identified, and 17/23 (73.9%) areas were present in LVAs, while they were at the border of the LVA and normal voltage areas in the remaining 6/23 (26.1%). Global activation histograms facilitated the identification of the critical isthmus in all. Tailor-made ablation at critical isthmuses successfully eliminated all ATs. However, one patient with AT related to functional linear block experienced recurrent AT related to dense scar, which progressed after the procedure. During a mean 14 ± 13 month follow-up after the last procedure, no patients experienced recurrent ATs without any complications.

CONCLUSION

LASARTs consist of not only fixed conduction blocks but also functional conduction blocks. Ultrahigh resolution mapping is highly useful to decide the optimal tailor-made ablation strategy based on the mechanisms.

Effects of Ranolazine and its Combination with Amiodarone on Rapid Pacing-induced Reentrant Atrial Tachycardia in Rabbits

Ranolazine (RAN) has previously been shown to lower the onset of cholinergic atrial fibrillation in intact animals; however, its efficacy in the setting of atrial tachycardia (AT) is unknown. The purpose of this study was to investigate the effects of RAN alone or in combination with amiodarone (AMIO) on rapid pacing-evoked right AT in rabbit hearts. Right atrial monophasic action potentials (MAPs) were recorded in 11 anesthetized rabbits, using combination MAP pacing catheters. Vulnerability to AT was tested by employing consecutive trains of rapid burst pacing prior to and after 2.4 mg/kg of RAN alone delivered intravenously and then in combination with 3 mg/kg of AMIO as a 15-minute infusion. Primary endpoints were postdrug AT reproducibility as well as cycle length (CL) and tachycardia duration. MAP duration at 75% repolarization and the effective refractory period (ERP) were assessed during programmed pacing to calculate the atrial postrepolarization refractoriness (aPRR = ERP – MAPD_75%). AT was elicited in eight out of 11 rabbits; only these animals were included for further investigation. RAN did not abolish the inducibility of AT in any experiment; however, it prolonged its CL (baseline vs. RAN: 120 ± 16 ms vs. 138 ± 18 ms; p = 0.053). Supplemental AMIO further increased the AT CL (baseline vs. RAN + AMIO: 120 ± 16 ms vs. 152 ± 23 ms; p = 0.006), without affecting arrhythmia reinducibility. Slowing of the tachycardia after RAN or RAN + AMIO was associated with spontaneous termination of the arrhythmia. RAN prolonged the aPRR significantly, while AMIO in addition to RAN potentiated this effect. Neither RAN alone nor its combination with AMIO abolished the elicitation of AT in this model. However, both agents synergistically prolonged the aPRR, resulting in the slowing of AT and promoting spontaneous termination of the arrhythmia.

The characteristics and efficacy of catheter ablation of focal atrial tachycardia arising from an epicardial site

BACKGROUND

Although epicardial structures around the atrium such as adipose tissue possess arrhythmogenicity, little is known about atrial tachycardias (ATs) originating from epicardial sites (Epi-ATs). This study aimed to elucidate the prevalence, characteristics, and outcome after radiofrequency catheter ablation (RFCA) of Epi-ATs and to reveal the association between Epi-ATs and the epicardial structures.

METHODS

The electrocardiographic, electrophysiologic, and anatomical properties and results of RFCA were analyzed in 42 patients with a total of 49 ectopic ATs.

RESULTS

Six Epi-ATs (12%) were observed in six patients (14%). Four of six were respiratory cycle-dependent ATs and one was a swallowing-induced AT. The Epi-AT origins were adjacent to a pulmonary vein (five cases) and vein of Marshall (one case). A Valsalva maneuver or atropine infusion to define the arrhythmia mechanism affected the appearance of the Epi-ATs. The congruity rate between epicardial adipose tissue and the AT origin was significantly higher (100% vs. 44%, p = .045), and the epicardial adipose tissue volume of the atrium was significantly larger (104.1 vs. 64.6 ml, p = .04) in the Epi-AT group. Endocardial RFCA targeting the AT foci resulted in acute success in five of five cases. However, electrical isolation including of the AT foci resulted in acute failures (two of three cases) or a recurrence (one of one case).

CONCLUSIONS

Six Epi-ATs were associated with thoracic veins and epicardial arrhythmogenic structures. The main cause provoking the Epi-ATs was associated with autonomic nerve activity.

The effect of posterior wall isolation for persistent atrial fibrillation on recurrent arrhythmia

INTRODUCTION

It is important to consider recurrent arrhythmia after catheter ablation for persistent atrial fibrillation (AF) for planning an ablation strategy. However, the studies are limited to pulmonary vein isolation (PVI) plus posterior wall isolation (PWI), which were reported to improve procedural outcomes. The objective of this study is to evaluate the effect of PWI on recurrent arrhythmia.

METHODS

This is an observational study on patients with persistent AF comparing PVI plus PWI and PVI only strategies. In PVI plus PWI group, linear ablation of the left atrium roofline and bottom line were performed to achieve PWI after PVI. Some patients with AF recurrence underwent the second procedure. The presence of recurrent arrhythmia and results of the second procedures were evaluated.

RESULTS

A total of 181 patients (mean age, 66.9 ± 10.2 years; male, 76.8%) were included. PVI plus PWI group and PVI only group consisted of 90 and 91 patients, respectively. AF recurrence was observed in 28 of 90 (31.1%) patients with PVI plus PWI and in 43 of 91 (47.3%) with PVI only, and log-rank test did not show any significant difference (p = .35). The occurrence of recurrent persistent AF was significantly lower in PVI plus PWI group than in PVI only group (5/90; 5.6% vs. 18/91; 20.9%, p = .002). There was no significant difference between the two groups in recurrent paroxysmal AF and atrial tachycardia (AT).

CONCLUSION

PWI, in addition to PVI, for persistent AF was significantly related to fewer episodes of recurrent persistent AF, and it did not increase recurrent AT.

Systematic Evaluation of High-Resolution Activation Mapping to Identify Residual Endocardial and Epicardial Conduction Across the Mitral Isthmus

OBJECTIVES

This study sought to systematically evaluate the ability of a high-resolution mapping system (Rhythmia, Boston Scientific, Marlborough, Massachusetts) to rapidly and accurately localize residual endocardial and epicardial conduction after mitral isthmus (MI) ablation, facilitating MI block.

BACKGROUND

Achieving conduction block across the mitral isthmus (MI) is challenging.

METHODS

Fifty consecutive patients undergoing MI ablation after pulmonary vein isolation were enrolled. After initial endocardial radiofrequency (RF) ablation across the lateral MI, high-resolution activation mapping of the MI with simultaneous coronary sinus (CS) mapping was performed to verify block or localize residual conduction across the MI during left atrial (LA) appendage and CS pacing. Propagation maps were used to identify residual conduction across the MI as endocardial, via the CS or Marshall tract.

RESULTS

In all 50 patients, after the initial endocardial ablation across the MI, repeat high-resolution mapping of the LA and CS was obtained (median: 3,329 mapped points; 4.0 min of mapping time). The initial endocardial MI ablation resulted in block in 9 of 50 patients (18%). In the remaining 41 patients, the propagation map identified residual conduction in 4 patterns: 1) only endocardial gap in 12 patients (29%); 2) only CS connection in 10 patients (24%); 3) both endocardial and CS connections in 14 patients (34%); and 4) Marshall tract connection in 5 patients (12%). In 8 patients, the propagation map revealed residual conduction, despite differential atrial pacing suggesting bidirectional block. Focal ablation at the identified residual conduction site (median: 0.7 min of RF) resulted in block in 49 of 50 (98%) patients.

CONCLUSIONS

High-resolution propagation maps of the LA/CS rapidly and accurately localize residual endocardial and epicardial conduction across the MI. Focal ablation with short RF time at the identified gap(s) achieved complete block across MI in 98% of cases.

Incessant Focal Atrial Tachycardia Leading to Tachycardiomyopathy

A 22-year-old man presented with severe left ventricular (LV) dysfunction and progressive heart failure. The 12-lead electrocardiogram showed short runs of supraventricular tachycardia suggestive of focal atrial tachycardia. The patient underwent successful radiofrequency ablation. There was a complete recovery of symptoms and LV function at six months of follow-up. We discuss the importance of identifying tachycardiomyopathy as a reversible cause of heart failure.

Ablation of Atrial Fibrillation in Patients With Hypertrophic Cardiomyopathy: Treatment Strategy, Characteristics of Consecutive Atrial Tachycardia and Long-Term Outcome

Background

Atrial fibrillation (AF) is common in patients with hypertrophic cardiomyopathy (HCM) and is associated with a deterioration of clinical status. Ablation of symptomatic AF is an established therapy, but in HCM, the characteristics of recurrent atrial arrhythmias and the long‐term outcome are uncertain.

Methods and Results

Sixty‐five patients with HCM (aged 64.5±9.9 years, 42 [64.6%] men) underwent AF ablation. The ablation strategy included pulmonary vein isolation in all patients and ablation of complex fractionated atrial electrograms or subsequent atrial tachycardias (AT) if appropriate. Paroxysmal, persistent AF, and a primary AT was present in 13 (20.0%), 51 (78.5%), and 1 (1.5%) patients, respectively. Twenty‐five (38.4%) patients developed AT with a total number of 54 ATs. Stable AT was observed in 15 (23.1%) and unstable AT in 10 (15.3%) patients. The mechanism was characterized as a macroreentry in 37 (68.5%), as a localized reentry in 12 (22.2%), a focal mechanism in 1 (1.9%), and not classified in 4 (7.4%) ATs. After 1.9±1.2 ablation procedures and a follow‐up of 48.1±32.5 months, freedom of AF/AT recurrences was demonstrated in 60.0% of patients. No recurrences occurred in 84.6% and 52.9% of patients with paroxysmal and persistent AF, respectively (P<0.01). Antiarrhythmic drug therapy was maintained in 24 (36.9%) patients.

Conclusions

AF ablation in patients with HCM is effective for long‐term rhythm control, and especially patients with paroxysmal AF undergoing pulmonary vein isolation have a good clinical outcome. ATs after AF ablation are frequently observed in HCM. Freedom of atrial arrhythmia is achieved by persistent AF ablation in a reasonable number of patients even though the use of antiarrhythmic drug therapy remains high.

The Left Atrial Appendage Ostium: Hotspots for Localized Re-Entry

OBJECTIVES

The goal of this study was to characterize the location and electrophysiological properties of left atrial appendage (LAA) atrial tachycardia (AT).

BACKGROUND

The LAA has been reported to be a source of AT and atrial fibrillation (AF) triggers.

METHODS

This study retrospectively reviewed ATs mapped to the LAA. Activation and entrainment mapping were used to determine the mechanism and localize each AT circuit/origin.

RESULTS

From 2014 to 2018, a total of 45 patients (mean age 65 ± 10 years; 69% male) had 51 LAA ATs: 43 (84%) after AF ablation and 8 de novo (no prior AF). Overall, 50 (98%) were due to localized re-entry/micro-re-entry, whereas only 1 was a focal triggered AT. All 50 micro-re-entrant LAA ATs were mapped to the anterior base (70%) or LAA ridge (30%), and all were successfully treated with focal ablation; no case required LAA isolation. After successful ablation of the initial AT at the LAA base, 23 (62%) of 37 patients with AF also had inducible macro-re-entrant peri-mitral flutter, but none had AF triggers from inside the LAA.

CONCLUSIONS

LAA ATs are almost always micro-re-entrant in mechanism and originate from either the anterior base or LAA ridge. AT originating from inside the LAA body is very rare. The anterior and ridge aspects of the LAA-left atrium junction seem to be arrhythmogenic hotspots prone to localized re-entry. These ATs are treatable with focal ablation without LAA isolation but are frequently associated with macro-re-entrant peri-mitral flutter.

Atrial Tachycardia Associated With a Tachycardia-Induced Cardiomyopathy in a Patient With Systemic Lupus Erythematosus

Systemic lupus erythematosus (SLE) is an autoimmune disease that involves multiple organ systems. Cardiovascular involvement in SLE is well described in the literature. Cardiac arrhythmias associated with SLE include sinus tachycardia, atrial fibrillation, and atrial ectopy or atrial tachycardia. In this report, we present the case of a patient with SLE who was found to have focal atrial tachycardia that mimicked sinus tachycardia on a 12-lead electrocardiogram (ECG). She was inappropriately treated as a case of sinus tachycardia initially. But she did not respond to the treatment and developed tachycardia-induced cardiomyopathy despite being on antiarrhythmic medications. She subsequently underwent successful radiofrequency catheter ablation and her left ventricular ejection fraction (LVEF) recovered within three months after the ablation.

Paroxysmal short runs of irregular narrow QRS tachycardia: What is the mechanism?

The present case that showed the frequent transition between left atrial tachycardia and AV nodal re-entrant tachycardia has never been reported. This instructive case highlights the need for careful interpretation of intracardiac electrocardiogram and suggests that differential pacing maneuvers are not feasible in transitional tachycardia with atrial fusion.

U-Shaped Association Between Intraoperative Net Fluid Balance and Risk of Postoperative Recurrent Atrial Tachyarrhythmia Among Patients Undergoing the Cryo-Maze Procedure: An Observational Study

OBJECTIVE

The ability of perioperative fluid management to prevent postoperative recurrence of atrial tachyarrhythmia remains controversial. The aim of the present study was to assess if intraoperative net fluid balance was associated with atrial tachyarrhythmia recurrence after the Cryo-Maze procedure.

DESIGN

An observational cohort study.

SETTING

A tertiary care hospital from April 2007 to May 2019.

PARTICIPANTS

Four hundred forty-four patients undergoing the Cryo-Maze procedure in conjunction with other cardiac surgeries.

INTERVENTIONS

The Cryo-Maze procedure in conjunction with other cardiac surgeries.

MEASUREMENTS AND MAIN RESULTS

The main outcome was early atrial tachyarrhythmia recurrence, consisting of atrial fibrillation, atrial flutter, or atrial tachycardia, within the first three months after surgery. Complete follow-up was achieved in 443 patients (99.8%), of them 127 (28.6%) developed early atrial tachyarrhythmia recurrence. The median intraoperative net fluid balance was 1,627 mL (interquartile range, -215 to 3,557 mL). Multivariate logistic regression showed that intraoperative net fluid balance (p = 0.001), preoperative AF duration (adjusted odds ratio, 1.40; 95% CI, 1.17-1.68; p < 0.001) and left atrial volume index (aOR, 1.61; 95% CI, 1.06-2.45; p = 0.025) were independent predictors of early atrial tachyarrhythmia recurrence. The adjusted log odds were lowest (-1.52) when net fluid balance was 1,557 mL.

CONCLUSIONS

There is a significant U-shaped association between intraoperative net fluid balance and early atrial tachyarrhythmia recurrence among patients undergoing the Cryo-Maze procedure.

[Current Status of Researches on Atrial Tachycardia Occurred after Atrial Fibrillation Catheter Ablation]

Atrial fibrillation is the most common persistent arrhythmia in the clinic. It affects a wide range of populations with high incidence, morbidity and mortality. Clinical studies have shown that ablation is one of the best means for the treatment of atrial fibrillation. However, after receiving ablation, some patients may experience atrial tachycardia and thus feel even deteriorated feelings. Understanding the predicting factors, electrophysiological mechanisms, and differential diagnosis and treatment strategies for post-ablation atrial tachycardia is essential for reducing the incidence and for the management of post-ablation atrial tachycardia. Therefore, we summarize the research progress of the above-mentioned aspects, and correspondingly proposes further research directions.

Catheter ablation for atrial tachycardias: How to interpret the unclear activation map?

BACKGROUND

Post-ablation atrial tachycardias (ATs) are characterized by low-voltage signals that challenge current mapping methods. In this study, we analyzed common mistakes during activation mapping and delineated a mapping strategy for correct interpretation of tachycardia mechanisms in patients with challenging underlying substrate.

METHODS AND RESULTS

Thirty-one patients referred for AT ablation were selected for the study. Three types of incorrect activation patterns were identified, which were referred to as unrecognized block line (pseudo-macroreentry and pseudo-fig-8 reentry), incorrect activation timing window of interest (WOI) (chaotic activation), and mis-annotation of complex signals (multiple sites of "early meets late"). Pseudo-macroreentry and chaotic activation occur in focal or localized reentry AT with the error related to the WOI selection (four cases), incorrect annotation of local activation time (six cases), or a previous line of atrial block in (seven cases). Pseudo-fig-8 reentry (five cases) and multiple sites of "early meets late" (nine cases) occur in macroreentrant AT with blocked areas and low-voltage atrial substrate. All ATs were successfully eliminated at the origin site.

CONCLUSIONS

We delineated a series of ATs in the setting of a disordered pattern of activation mapping encountered in patients after previous extensive ablation or atriotomy. The algorithm proposed rapidly corrects the activation map and identifies the mechanism of the AT.

Outcomes of Atrial Arrhythmia Surgery in Patients With Congenital Heart Disease: A Systematic Review

Background The improved life expectancy of patients with congenital heart disease is often accompanied by the development of atrial tachyarrhythmias. Similarly, the number of patients requiring redo operations is expected to continue to rise as these patients are aging. Consequently, the role of arrhythmia surgery in the treatment of atrial arrhythmias is likely to become more important in this population. Although atrial arrhythmia surgery is a well-established part of Fontan conversion procedures, evidence-based recommendations for arrhythmia surgery for macroreentrant atrial tachycardia and atrial fibrillation in other patients with congenital heart disease are still lacking. Methods and Results Twenty-eight studies were included in this systematic review. The median reported arrhythmia recurrence was 13% (interquartile range, 4%-26%) during follow-up ranging from 3 months to 15.2 years. A large variation in surgical techniques was observed. Based on the acquired data, biatrial lesions are more effective in the treatment of atrial fibrillation than exclusive right-sided lesions. Right-sided lesions may be more appropriate in the treatment of macroreentrant atrial tachycardia; evidence for the superiority of additional left-sided lesions is lacking. There are not enough data to support the use of exclusive left-sided lesions. Theoretically, prophylactic atrial arrhythmia surgery may be beneficial in this population, but evidence is currently limited. Conclusions To be able to provide recommendations for arrhythmia surgery in patients with congenital heart disease, future studies should report outcomes according to the type of preoperative arrhythmia, underlying congenital heart disease, lesion set, and energy source. This is essential for determining which surgical techniques should ideally be applied under which circumstances.

Maternal focal atrial tachycardia during pregnancy: A systematic review

INTRODUCTION

The presentation and optimal management of maternal focal atrial tachycardia (AT) during pregnancy are unknown. The objective of this study is to conduct a comprehensive summary of the existing evidence.

METHODS AND RESULTS

A systematic review of all reported cases of maternal focal AT during pregnancy was performed. The primary search queried PubMed using the MeSH terms "supraventricular tachycardia" and "pregnancy." A stepwise ancillary search included article bibliographies, citations listed by the Google internet search engine, and PubMed using the MeSH terms "atrial tachycardia" and "pregnancy." In total, 28 citations that described 32 patients were retrieved. A case from our institution was added. Detailed information was available for 30 patients. Clinical characteristics at presentation included a mean ± standard deviation of 28.3 ± 5.7 years for maternal age and 24.6 ± 7.7 weeks for gestation age. Suspected tachycardia-induced cardiomyopathy was present in 20 of 30 (67%) patients and left ventricular ejection fraction improved in 15 of 15 (100%) patients with follow-up measurements. Medication failure was common. Focal AT resolved spontaneously after delivery in eight of nine (89%) patients treated with only medications. Automaticity was suggested by discrete electrograms at sites of origin and lack of reported inducibility and termination with programmed stimulation in all patients who underwent electrophysiology studies. There were nine cases of successful catheter ablation with zero fluoroscopy since 2010.

CONCLUSIONS

Automaticity is the dominant mechanism for patients with maternal focal AT during pregnancy. Catheter ablation with zero fluoroscopy is an emerging therapy for medically refractory cases.

Extensive scar modification for the treatment of intra-atrial re-entrant tachycardia in patients after congenital heart surgery

BACKGROUND

Catheter ablation is an important therapeutic option for atrial tachycardias in patients with CHD. As a result of extensive scarring and surgical repair, multiple intra-atrial re-entrant tachycardia circuits develop and serve as a substrate for arrhythmias. The best ablation approach for patients with multiple intra-atrial re-entrant tachycardias has not been investigated. Here, we compared substrate-based ablation using extensive scar modification to conventional ablation.

METHODS

The present study included patients with surgically corrected CHD that underwent intra-atrial re-entrant tachycardia ablation. Extensive scar modification was defined as substrate ablation based on a dense voltage map, aimed to eliminate all potentials in the scar region. The control group had activation mapping-based ablation. A clinical composite endpoint was assessed. Points were given for type, number, and treatment of intra-atrial re-entrant tachycardia recurrence.

RESULTS

In 40 patients, 63 (extensive scar modification 13) procedures were performed. Acute procedural success was achieved in 78%. Procedural duration was similar in both groups. Forty-nine percent had a recurrence within 1 year. During a 5-year follow-up (2.5-7.5 years), 46% required repeat catheter ablation. Compared to baseline, clinical composite endpoint significantly decreased by 46% after 12 months (p = 0.001). Acute procedural success, procedural parameters, recurrence and repeat ablation were similar between extensive scar modification and activation mapping-based ablation.

CONCLUSION

Catheter ablation using extensive scar modification for intra-atrial re-entrant tachycardias occurring after surgically corrected CHD illustrated similar short- and long-term outcomes and procedural efficiency compared to catheter ablation using activation mapping-based ablation. The choice of ablation approach for multiple intra-atrial re-entrant tachycardia should remain at the discretion of the operator.