Radiofrequency catheter ablation of atrial tachycardias related to myocardial scar or incision

Intra-atrial re-entrant tachycardias (IARTs) are common late after heart surgery. Conventional mapping and ablation is relatively difficult because of the complicated anatomy and multiple potential re-entry loops. In this study we aimed to evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) induced by myocardial scar or incision. Methods In 6 patients (three male and three female, aged 33.3+ 11.8 years) who had AT related to myocardial scar or incision,electrophysiological study and radiofrequency catheter ablation (RFCA) were performed. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Results Re-entry related to the lateral atriotomy scar was inducible in 5 of6 patients. With entrainment mapping, the PPI (post-pacing interval)-TCL (tachycardia cycle length) difference was ＜30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 3 patients had successful linear ablation between scar area to inferior vena cava, and 2 patients between scar area to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 6 patients. PPI-TCL differences ＜30 ms were observed when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of AT related to incision was observed during follow-up except for the failed patient. Conclusion Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation can be obtained in patients with IRATs related to myocardial scar or incision.

Ivabradine—The Final Crusader for Postoperative Junctional Ectopic Tachycardia, a Case Report with Literature Review

Background: Junctional ectopic tachycardia (JET) is one troublesome supraventricular arrhythmia in postoperative pediatric cardiac surgical patients. Unless treated timely and effectively it may lead to morbidity and even mortality. Aim: To understand the role of Ivabradine in the treatment of JET in postoperative pediatric cardiac surgical patients. Case: We present a postoperative case of complete repair of Tetralogy of Fallot who was in normal sinus rhythm in the preoperative period and developed JET 4 hours later in postoperative period which was persistent despite measures to optimize the internal milieu of the body and conventional antiarrhythmics, that was successfully treated with Ivabradine at a dose of 0.05 mg/kg/12 hourly. Conclusion: Ivabradine can be used to successfully treat postoperative JET in cases ofrefractory to other antiarrhythmic drugs like Digoxin and Amiodarone.

A Case Report of Radiofrequency Ablation of Typical Atrial Flutter Combined with Atrial Tachycardia

A 63-year-old female patient with a history of pulmonary heart disease underwent radiofrequency ablation because of a persistent atrial fl utter.Endocardial mapping with the carto3 system confi rmed atrial fl utter counterclockwise reentry around the tricuspid annulus.Routine ablation of the cavo-tricuspid isthmus line to bi-directional block was performed.However,tachycardia with the same cycle length was induced again.After remapping,the tachycardia was confi rmed to be focal atrial tachycardia located in the crista terminalis.After ablation,the tachycardia was terminated and could not be induced again.

Lactic Acidosis and Atrial Tachycardia: Unusual Presentations of Disseminated Burkitt-Like Lymphoma

Lactic acidosis is a rare complication of malignancies and is seen more frequently in high grade lymphoma and leukemia. Although, its pathogenesis is not well understood, it remains a surrogate of poor prognosis. Herein, we present a case of Burkitt-like lymphoma presenting with metabolic abnormalities including lactic acidosis and hypoglycemia along with atrial tachycardia. We will discuss the different mechanisms involved in these metabolic disturbances and we will provide insight on novel therapeutic strategies based on our understanding of the underlying pathophysiology.

Incidence and Related Risk Factors of Junctional Ectopic Tachycardia in Infants after Cardiac Surgery for Congenital Heart Disease

Objective:Junctional ectopic tachycardia is common after cardiac surgery for congenital heart disease.However,its incidence and related risk factors in infants after cardiac surgery are not well known.The objective of this study was to determine the overall incidence and related risk factors for junctional ectopic tachycardia in neonates and infants.Methods:We enrolled a total of 271 patients aged<1 year who underwent open cardiac surgery at Severance Cardiovascular Hospital from January 2018 to December 2020.Exclusion criteria were immediate postoperative mortality,other arrhythmias detected in the perioperative period,and prematurity.Result:The overall incidence of junctional ectopic tachycardia was 12.9%.The logistic regression analysis revealed that longer cardiopulmonary bypass time,surgery involving atrioventricular node stretching,and the presence of early repolarization on preoperative electrocardiography increased the risk of junctional ectopic tachycardia.Patients with junctional ectopic tachycardia had longer intubation time and intensive care unit stay.Conclusion:Junctional ectopic tachycardia is a common arrhythmia after cardiac surgery for congenital heart disease in infants.Occasionally,infants developing junctional ectopic tachycardia after cardiac surgery have specific preoperative electrocardiography findings.The risk factors for junctional ectopic tachycardia were associated not only with surgical procedural factors but also with preoperative electrocardiographic parameters.

Electrophysiological characteristics of atrial tachycardia originating from the coronary sinus

A 22-year-old girl was admitted to our cardiology institute with Permanent tachycardia in last 6 years for diagnostic assessment and therapy. Doppler echocardiography show structural of heart is normal, ECG revealed a varied resting rate from 120 to 140 bpm, 1:1 AV ratio and long RP interval. P wave morphology was negative on leads I, II, III, aVF, and V4 to V6, positive on lead V1, and diphasic 1 /2 on lead aVL. Electrophysiology (EP) study was performed, Although the exactly mapping was performed in left inferior pulmonary vein and mitral annulus, however, no target point was found ahead of CS1-2, the tried discharge was invalid. The ablation catheter was entered the coronary sinus to guide electrical isolation, curing the tachycardia. The ECG returned to normal sinus rhythm. Through three years follow up, no AT recurrence.

Radiofrequency ablation of atrial tachycardia in patients with repaired atrial septal defect

Objective:To evaluate the electrophysiological characteristics and radiofrequency catheter ablation of atrial tachycardia (AT) in patients with repaired atrial septal defects(ASD). Methods: In 76 consecutive patients with AT who underwent the electrophysiological study and radiofrequency catheter ablation (RFCA). 4 patients (one male and three female aged 35. 5±11. 5 years) had AT-related myocardial scar or incision. Earliest activation combined with entrainment mapping was adopted to determine a critical isthmus. Results: Re-entry related to the lateral atriotomy scar was inducible in 3 of 4 patients. With en-trainment mapping, the PPI-TCL difference was <30 ms when pacing at the inferior margins of the right lateral atriotomy scar. Among them, 2 patients had successful linear ablation between scar area to inferior vena cava, and 1 patient between scar areas to tricuspid annulus. Re-entry involving an ASD patch was demonstrated in 1 of 4 patients. PPI-TCL differences <30 ms were found when entraining tachycardia at sites near the septal patch. But linear ablation failed in terminating AT. There was no complication during procedure. No recurrence of incision-related AT was found during follow-up except for the failed patient. Conclusion: Under conventional electrophysiological mapping, adopting linear ablation from scar area to anatomic barrier, successful ablation also can be obtained in patients with IRAT related to myocardial scar or incision.

Inadvertent isolation of a focal tachycardia within the superior vena cava

The superior vena cava (SVC) is known to be a potential source of focal atrial tachycardias. Not uncommonly these tachycardias trigger atrial fibrillation or flutter. Focal ablation is safe and effective in eliminating arrhythmogenic foci within the SVC. We present the case of a patient with focal atrial tachycardia arising from the SVC. During presumably focal ablation inadvertent electrical isolation of the SVC from the right atrium was achieved, with restoration of sinus rhythm in the atria and persistence of the tachycardia within the SVC.

Plasma natriuretic peptides during supraventricular tachycardia: A study in patients with atrioventricular nodal reentry tachycardia

Aims: To characterize the plasma levels of the atrial natriuretic peptide (ANP) and brain natriuretic peptide (BNP) in patients with atrioventricular nodal reentry tachycardia (AVNRT), we measured the plasma levels of these peptides before and during tachycardia. Methods: We included 10 consecutive patients scheduled for ablation of typical AVNRT without structural heart disease. Catheters were inserted in the femoral artery, femoral vein, and coronary sinus (CS) prior to the ablation procedure. Blood samples were drawn before and after 3 min of tachycardia to measure plasma levels of ANP and BNP. Right atrial pressure (RAP) was measured at baseline. Results: Of the 10 patients, in three patients it was not possible to induce tachycardia leaving a total of 7 patients available for analysis. Mean age of the seven included patients was 40 ± 12 years (mean ± SD), five were female. ANP levels increased significantly during tachycardia in the artery (p = 0.0009) and vein (p = 0.003), but only borderline in CS (p = 0.09). BNP levels did not change during tachycardia in any location. Conclusion: ANP levels measured in the peripheral circulation increased acutely during tachycardia due to AVNRT. BNP levels did not increase.

Mechanisms of organized atrial tachycardia during catheter ablation of chronic atrial fibrillation by stepwise approach

Background Extensive atrial fibrillation （AF） ablation is associated with an increased success rate of catheter ablation in chronic AF patients and an increased rate of atrial tachycardia （AT） during the procedure. The mechanism of these Ats varies in previous studies. Our study aimed to report the mechanism of organized AT occurring during the stepwise ablation procedure of chronic AF.Methods A prospective cohort of 86 consecutive patients who underwent an ablation procedure for chronic atrial fibrillation （CAF） was investigated. The stepwise procedure was performed in the following order： circumferential pulmonary vein ablation, complex fractionated atrial electrograms ablation, mapping and ablation of AT. The endpoint was noninducibility of AF/AT after sinus rhythm （SR） was restored or the procedure time was beyond 6 hours.Results Sixty-nine （80%） of patients converted to SR via AT. A total of 179 sustained ATs were observed in 69 patients during the procedure. There were 81% （n=145） macroreentrant ATs which included 65 perimitral circuits, 48 peritricuspid tachycardia and 32 roof dependent circuits, 12% （n=21） localized reentrant and 7% （n=13） focal ATs. Thirty （15%） patients experienced significant left atrium （LA） and LA appendage （LAA） conduction delay or dissociation in the procedure or during the follow-up period.Conclusions Most CAF patients converted to SR via ablation of organized AT occurring during the stepwise procedure. The mechanism of most of these ATs was macro-reentry.

Pulmonary vein tachycardia after pulmonary vein isolation in patients with atrial fibrillation

Background Pulmonary vein （PV） isolation has been developed to treat patients with atrial fibrillation （AF）, and the electrophysiological endpoint of PV isolation is the disappearance or dissociation of pulmonary vein potentials （PVPs）. Pulmonary vein tachycardia （PVT） is the dissociated PV rhythm with a rapid rate. However, the characteristics and significance of PVT after pulmonary vein isolation in patients with AF remains unclear. Methods From June 2003 to June 2005, a total of 285 consecutive patients with drug refractory AF were included in this study, and they underwent segmental pulmonary vein ablation （SPVA） or circumferential pulmonary vein ablation （CPVA）. PV isolation was the initial endpoint for both approaches with documenting disappearance or dissociation of PVPs. PVT was characterized as dissociated activities within PVs with a circle length （CL） of 〈300 ms, and was classified into organized PVT or disorganized PVT according to the variance of CL. Systematic follow-up was conducted after initial procedures. Continuous variables were analyzed by Student＇s t test and categorical variables were analyzed by chi-square test. Results Three hundred and fifteen PVs were ablated in 85 patients underwent SPVA approach, 400 circular lesions surrounding ipsilateral PVs （including 790 PVs） were produced in the rest of 200 patients received CPVA approach. Electrical isolation was achieved in all of these PVs. Of these, PVPs were abolished in 89.8% （992/1105） of the ablated PVs, dissociated PV rhythms were documented in the rest 10.2 % （113/1105） of the treated PVs. Among the 113 dissociated PV rhythms, 28 met the criteria of PVT with mean CL of （155±43） ms （2 PYTs in 2 patients received SPYA, 26 PYTs in 18 patients underwent CPVA）. PVT was more frequently documented in patients underwent CPVA approach [9.0% （18/200） vs 2.3% （2/85）, P=0.04]. During the 6-month follow-up, it was indicated that no significant difference existed in AF free rate between patients with PVT and those without PVT （P=0.75）. Conclusions PVT dissociated from LA activations can be documented after PV isolation, especially in patients underwent CPVA approach. However, PVT does not affect the follow-up results.

Changes of atrial natriuretic peptide and antidiuretic hormone in children with postural tachycardia syndrome and orthostatic hypertension： a case control study

Background The abnormal blood volume regulation is one of the most important pathogenesis in postural tachycardia syndrome in children.This study was designed to investigate the plasma atrial natriuretic peptide and antidiuretic hormone levels in postural tachycardia syndrome children,and their associations with the changes in heart rate and blood pressure in head-up test.Methods Twenty-one postural tachycardia syndrome patients （（12±2） years） and 26 healthy children （（12±1） years） were included.According to blood pressure changes in head-up test,the postural tachycardia syndrome patients were divided into two subgroups：postural tachycardia syndrome with orthostatic hypertension and postural tachycardia syndrome without orthostatic hypertension.The plasma atrial natriuretic peptide and antidiuretic hormone levels were measured using enzyme-linked immunosorbent assay.Results The plasma atrial natriuretic peptide level in postural tachycardia syndrome patients was higher than the control （P=0.004）,whereas the difference in plasma antidiuretic hormone level between postural tachycardia syndrome and controls was not significant （P=0.222）.The plasma antidiuretic hormone level of patients suffering from postural tachycardia syndrome with orthostatic hypertension was much higher than that of children having postural tachycardia syndrome without orthostatic hypertension （P ＜0.05）.In postural tachycardia syndrome patients,the updght max heart rate was positively correlated with the plasma atrial natriuretic peptide level （r=0.490,P＜0.05） and the upright systolic blood pressure was positively correlated with the plasma antidiuretic hormone levels （r=0.472,P ＜0.05）.Conclusions There was a disturbance of plasma atrial natriuretic peptide and antidiuretic hormone in postural tachycardia syndrome children.

Image integration system to guide catheter ablation of atrial tachycardia with a multi-key-isthmus reentrant in a patient with a repaired atrial septal defect： a case report

Recurrent atrial tachycardia （AT） is often observed late .after heart surgery and it contributes significantly to the morbidity and mortality of this group of patients. In patients with structurally normal hearts the most prevalent type of AT is a macroreentrant atrial tachycardia （MAT）, more specifically known as common atrial flutter （AFL）. In contrast, in patients with repaired structural heart disease other ATs may occur due to the existence of variable and multiple arrhythmogenic substrates, related to the underlying heart disease and/or the surgical incisions.

Unipolar electrogram in identification of successful targets for radiofrequency catheter ablation of focal atrial tachycardia

Objective To analyze the unipolar electrogram from successful and unsuccessful ablation sites of focal atrial tachycardia (AT), and to evaluate its value in the identification of successful targets.Methods Fifteen consecutive patients with focal AT were referred for radiofrequency catheter ablation (RFCA). Both unipolar (from the tip electrode of ablating catheter) and bipolar (from the distal pair of electrode of ablating catheter) electrograms were used to identify the ablation targets of focal AT.Results Successful ablation was echieved in 14 patients. Radiofrequency energy was delivered at a total of 27 sites. The bipolar electrograms associated with successful ablation sites showed earlier atrial deflection relative to P wave onset (36 ms±15 ms vs 30 ms±11 ms, P <0.05) than the electrograms associated with failed ablation sites. At the 14 successful ablation sites, the unipolar electrograms displayed a completely negative atrial wave (“QS” morphology ) beginning with intrinsic deflection. However, at the 13 unsuccessful ablation sites,a “rS” morphology of atrial wave was shown on the unipolar electrogram.Conclusion The “QS” morphology of the atrial wave on unipolar electrograms appears to represent a reliable marker for identifying the successful ablation targets of focal AT, with a high sensitivity and specificity .

Biatrial Macroreentry Atrial Tachycardia after Atria Fibrillation Ablation

Catheter ablation is an important therapy for atrial fibrillation （AF） in the last decade. In parallel, atrial tachycardia （AT） has become the most common type of arrhythmia after AF ablation, especially after extensive left atrial （LA） substrate modification,t^j The occurrence of AT after AF is due to the conduction gaps of ablation lines and the conduction obstacle caused by the ablation lesions？-~1 Most of these ATs locate in LA, and here, we described a biatrial macroreentry AT （MAT） after AF ablation.

Late intra-atrial reentrant tachycardia would be prevented by ablation of right atrial potential isthmuses during the surgical operation for congenital heart disease

Intra-atrial reentrant tachycardia （IART） is not uncommon after surgical correction of congenital heart disease （CHD）. The patients with IART are often refractory to antiarrhymic agents and present with severe symptoms. Current treatment approach to IART has shifted largely to interventional procedures which have a good short-term success rate, however, late recurrence rate is still high. With the development of mapping technique especially the application of three-dimensional electroanatomic mapping,

Radiofrequency catheter ablation in patients with symptomatic atrial flutter/tachycardia after orthotopic heart transplantation

Background Atrial tachycardia or flutter is common in patients after orthotopic heart transplantation. Radiofrequency catheter ablation to treat this arrhythmia has not been well defined in this setting. This study was conducted to assess the incidence of various symptomatic atrial arrhythmias and the efficacy and safety of radiofrequency catheter ablation in these patients. Methods Electrophysiological study and catheter ablation were performed in patients with symptomatic tachyarrhythmia. One Halo catheter with 20 poles was positioned around the tricuspid annulus of the donor right atrium, or positioned around the surgical anastomosis when it is necessary. Three quadripolar electrode catheters were inserted via the right or left femoral vein and positioned in the recipient atrium, the bundle of His position, the coronary sinus. Programmed atrial stimulation and burst pacing were performed to prove electrical conduction between the recipient and the donor atria and to induce atrial arrhythmias. Results Out of 55 consecutive heart transplantation patients, 6 males [（58±12） years] developed symptomatic tachycardias at a mean of （5±4） years after heart transplantation. Electrical propagation through the suture line between the recipient and the donor atrium was demonstrated during atrial flutter or during recipient atrium and donor atrium pacing in 2 patients. By mapping around the suture line, the earliest fragmented electrogram of donor atrium was assessed. This electrical connection was successfully ablated in the anterior lateral atrium in both patients. There was no electrical propagation through the suture line in the other 4 patients. Two had typical atrial flutter in the donor atrium which was successfully ablated by completing a linear ablation between the tricuspid annulus and the inferior vena cava. Two patients had atrial tachycardia which was ablated in the anterior septal and lateral donor atrium. There were no procedure-related complications. Patients were free of recurrent atrial tachyarrhythmias after a follow-up of （8± 7） months. Confusions Four electrophysiological mechanisms have been found to contribute to the occurrence of symptomatic supraventricular arrhythmias following heart transplantation. Radiofrequency catheter ablation in patients with atrial flutter/tachycardia is feasible and safe after heart transplantation.

An incessant atrial tachycardia originating from epicardial left atrial appendage in a 12-year-old girl:ablation or excision?

To the Editor: Left atrial appendage (LAA) is one of the major sources of atrial arrhythmias in children.[1] But atrial tachycardia (AT) with an epicardial LAA origin is uncommon and usually arises from the base.[2] Catheter ablation (CA) may be an important strategy for patients with atrial arrhythmia,[3] especially due to the LAA firing trigger.[4] Due to a large number of trabeculations and true epicardial location, endocardial CA in LAA may fail or even cause fatal tamponade.[2,5] The epicardial CA may be an alternative approach.[6] Because the LAA has a very thin wall and may be prone to perforation, caution should be taken when LAA ablation is performed,[4] even during an epicardial ablation. There may be recurrence of AT, and surgical left atrial appendectomy (SAE) may be required.

Radiofrequency ablation for treating paroxysmal supraventricular tachycardia complicated by atrial fibrillation： A single-center retrospective analysis

The effect of selective radiofrequency ablation for treating paroxysmal supraventricular tachycardia （PSVT） and its associated paroxysmal atrial fibrillation （PAF） was assessed. Methods Data were collected retrospectively from patients diagnosed of PSVT and subsequently treated with radiofrequency ablation. Regular monthly follow-up by dynamic electrocardiography （ECG） was performed. Incident rates of atrial fibrillation before and after ablation were compared. Results 382 PSVT patients with 58 having atrial fibrillation were en- rolled. The order of complicated PAF from high to low in these patients was displayed as： atrial tachycardia （AT）, atrioventricular reentrant tachycardia （AVRT） and atrioventricular nodal reentrant tachycardia （AVNRT）. Among AVRT patients, PAF was more frequent in patients having accessory pathways. AVNRT patients had significant- ly lower PAF rate comparing to other patients. PAF incident rate was significantly reduced by radiofrequency ablation therapy. Conclusion We advise regular dynamic ECG for PSVT patients, especially those with atrial flutter, AT or pre-excitation syndrome. Selective radiofrequency ablation is a feasible approach for treating AF complicated PSVT patients.

Complex atrial tachycardia with alternating cycle length:What is the mechanism?

Background Atrial tachycardia(AT)with cycle length(CL)alternans is uncommon and conventional mapping of this AT remains challenging. We used an ultrahigh density mapping system to rapidly map complicated circuits with sufficient spatial resolution and electrogram quality to elucidate the precise mechanism of this special ATs. Methods Of 210 consecutive patients with clinical ATs who underwent catheter ablation with the ultrahigh density mapping system,4 patients(1.9%)with CL alternans were identified. The AT alternating cycles mapped by the Rhythmia mapping system for long CL were 317±51(range 245-355)ms and for short CL were 282±51(range 235-333)ms. Both long and short cycles followed in 1∶1 sequence in all 4 patients(longshort-long-short). Results By comparing the separate maps with long and short CL,we classified ATs with CL alternans into 2 types. In type 1,CL alternans resulted from an intermittent 2∶1 conduction block through the slow conduction channel in the small circuit. In type 2,CL alternans caused by the alternated conduction velocity passing through the conduction gap were manifested. Ablation at the fractionated potentials contributes to the termination of AT in 3 of the 4 patients. Conclusions Ultrahigh density mapping system can accurately identify the mechanism of complex ATs with alternating CL. The CL alternans may be related to the intermittent conduction block within the channel of the small circuitor different conduction velocity through the identical channel. Fractionated electrogram recorded in the common isthmus or some"conduction gaps"may be a reasonable approach to terminate these ATs.