Intra-atrial Reentrant Tachycardia Circuits Research Articles

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

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. 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. 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. 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.

Efficacy of Radiofrequency Catheter Ablation for Intraatrial Reentrant Tachycardia with Congenital Heart Disease

Background: Intraatrial reentrant tachycardia (IART) occurs frequently in patients with congenital heart disease (CHD) and is difficult to treat. Objectives: The objective of this study was to determine the success rates of radiofrequency ablation in reducing clinical arrhythmic events in patients with IART and CHD. Results: From June 2006 to March 2011, 48 consecutive patients (24 males, age [mean ± SD] 27.3±13.4 years; total 57 sessions) with 95 circuits of IART that complicated the surgery for congenital heart disease underwent ablation. The documented events of IART after surgical repair of CHD were 14.2±9.10 years. Success for one or more IART circuits was achieved in 36 patients (75%). The mean follow-up period of these patients was 25.4±17.8 months. IART recurrence was noted after successful catheterization in 9 (25%) of 36 patients. Among these 9 patients, 6 underwent repeat ablations and 3 were readministered antiarrhythmic medications. Conclusions: In patients with successful ablation, the frequency of arrhythmic events reduced compared to that before ablation. However, recurrence of IART in patients who showed clinical improvement was frequent, and careful clinical observation was important.

Outcome of Intra-Atrial Re-Entrant Tachycardia Catheter Ablation in Adults With Congenital Heart Disease: Negative Impact of Age and Complex Atrial Surgery

The aim of this study was to determine the acute and long-term outcome of radiofrequency catheter ablation (RFCA) for intra-atrial re-entrant tachycardia (IART) in adults with congenital heart disease (CHD), and predictors of these outcomes. Atrial myopathy can be progressive in CHD and contributes to the substrate for IART. Although the outcome of RFCA for IART has been well described in children and adolescents with CHD, it is unclear whether these results are similar in the adult population. Clinical records of adults with CHD undergoing attempted RFCA of IART were analyzed retrospectively. Multivariate analyses identified clinical and procedural factors that predicted acute and long-term outcomes. A total of 193 procedures was performed in 130 patients (mean age 40 ± 13 years); 82 of 118 (69%) initially attempted RFCA were successful, defined as termination of all IART circuits. The use of electroanatomic mapping was associated with a successful RFCA, whereas Fontan palliation and Mustard repair were associated with an unsuccessful RFCA. Median clinical follow-up of 77 patients (≥2 months of follow-up) after a successful RFCA was 3.7 years (range 0.2 to 10.2 years). IART recurrence was noted in 48%, cardioversion/reablation in 42%, and death in 4%. Older age and Fontan palliation were independent predictors of IART recurrence. In adults with CHD, acute and long-term outcomes of RFCA for IART are similar to those reported for younger cohorts. Complex atrial surgery limits the success of RFCA, and older age is associated with a higher risk of IART recurrence.

Interventional Electrophysiology in Patients With Congenital Heart Disease

“The treatment of congenital heart disease is unsatisfactory. As a rule, nothing can be done to improve patients symptomatically; in some instances digitalis may be of help.” — —L. Emmett Holt, MD, 1933 On August 26, 1938, Dr Robert Gross performed the first successful surgery for a congenital heart defect by closing a patent ductus arteriosus in a 7-year-old girl. The event marked the beginning of an interventional approach to congenital heart disease (CHD) that forever banished the sort of pessimism expressed by Dr Holt in his classic pediatric textbook only 5 years earlier.1 Subsequent diagnostic and operative innovations ultimately led to surgical solutions for nearly all anatomic heart defects, allowing the vast majority of infants born with CHD in the modern era to survive into adulthood. However, improved hemodynamic longevity has exposed alternate sources of morbidity and mortality for this population, central among which are cardiac rhythm disorders. In some instances, arrhythmias are intrinsic to the CHD lesion itself, but in most cases, they arise as an unintended consequence of prior corrective surgery whenever patches and suture lines function in conjunction with hypertrophy and fibrosis to create the substrate for reentrant tachycardias. It is fortunate that improved understanding of rhythm abnormalities in CHD has coincided with the emergence of interventional electrophysiological techniques. Catheter ablation, arrhythmia surgery, pacemakers, and implantable defibrillators have now become indispensable treatment options for this group. It is the purpose of this article to review the application of these tools to CHD with an emphasis on unique technical challenges. Congenital heart defects occur in roughly 0.8% of live births, and in 30% to 50% of cases, the malformations are severe enough to warrant ≥1 surgical procedures during early childhood.2 Arrhythmia mechanisms vary according to the underlying anatomic defect and method of surgical repair. The …

Prevalence of and risk factors for atrial fibrillation and intra-atrial reentrant tachycardia among patients with congenital heart disease

Atrial arrhythmias are common late sequelae of congenital heart disease (CHD), and several reports have documented their high prevalence in the late postoperative period. 1 Bink-Boelkens M.T. Meuzelaar K.J. Eygelaar A. Arrhythmias after repair of secundum atrial septal defect the influence of surgical modification. Am Heart J. 1988; 115: 629-633 Crossref PubMed Scopus (43) Google Scholar , 2 Roos-Hesselink J. Perlroth M.G. McGhie J. Spitaels S. Atrial arrhythmias in adults after repair of tetralogy of Fallot Correlations with clinical, exercise, and echocardiographic findings. Circulation. 1995; 91: 2214-2219 Crossref PubMed Scopus (225) Google Scholar , 3 Gelatt M. Hamilton R.M. McCrindle B.W. Connelly M. Davis A. Harris L. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Arrhythmia and mortality after the Mustard procedure a 30-year single-center experience. J Am Coll Cardiol. 1997; 29: 194-201 Crossref PubMed Scopus (393) Google Scholar , 4 Gelatt M. Hamilton R.M. McCrindle B.W. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Risk factors for atrial tachyarrhythmias after the Fontan operation. J Am Coll Cardiol. 1994; 24: 1735-1741 Crossref PubMed Scopus (231) Google Scholar These arrhythmias are associated with impaired quality of life, increased risk of thromboembolism, and death. They are difficult to control, with variable response to antiarrhythmic drug therapy, repeated cardioversion, and ablative and surgical intervention. The etiology, mechanism, and clinical significance of intra-atrial reentry tachycardia (IART) have been characterized in patients with CHD by epidemiologic study, 4 Gelatt M. Hamilton R.M. McCrindle B.W. Gow R.M. Williams W.G. Trusler G.A. Freedom R.M. Risk factors for atrial tachyarrhythmias after the Fontan operation. J Am Coll Cardiol. 1994; 24: 1735-1741 Crossref PubMed Scopus (231) Google Scholar in animal models, 5 Rodefeld M.D. Bromberg B.I. Schuessler R.B. Boineau J.P. Cox J.L. Huddleston C.B. Atrial flutter after lateral tunnel construction in the modified Fontan operation a canine model. J Thorac Cardiovasc Surg. 1996; 111: 514-526 Abstract Full Text Full Text PDF PubMed Scopus (82) Google Scholar and by electroanatomic mapping and ablation. 6 Love B.A. Collins K.K. Walsh E.P. Triedman J.K. Electroanatomic characterization of conduction barriers in sinus/atrially paced rhythm and association with intra-atrial reentrant tachycardia circuits following congenital heart disease surgery. J Cardiovasc Electrophysiol. 2001; 12: 17-25 Crossref PubMed Scopus (95) Google Scholar In contrast, atrial fibrillation (AF) is less well understood in these patients. This study describes a large cohort of patients with CHD with late atrial arrhythmias. We sought to identify the clinical and temporal characteristics that distinguish patients with AF and with IART, and to ascertain whether there was any temporal evolution between the 2 arrhythmias.

Influence of patient factors and ablative technologies on outcomes of radiofrequency ablation of intra-atrial re-entrant tachycardia in patients with congenital heart disease

ObjectivesThe goal of this study was to identify factors associated with radiofrequency catheter ablation (RFCA) outcomes of intra-atrial re-entrant tachycardia (IART). BackgroundRadiofrequency catheter ablation of IART is difficult. The influence of patient and procedural factors and novel technologies on outcomes is unknown. MethodsAcute and chronic RFCA outcomes were studied in patients with congenital heart disease and IART. Clinical status was measured using a multiaxis severity score. Multivariate analyses identified associations of clinical, procedural and technological factors with outcomes. ResultsA total of 177 procedures were performed in 134 patients; 139 procedures (79%) resulted in RFCA of ≥1 IART circuit and 117 (66%) in RFCA of all targeted circuits. Multivariate analysis associated acute success with irrigated ablation and absence of atrial fibrillation. Twenty-two complications were noted, nine related to vascular access. Electroanatomic mapping failed to decrease procedure or fluoroscopy time. Improvement in clinical status occurred in most patients (severity score preablation: 6.2 ± 1.6, postablation: 3.0 ± 2.3, p < 0.0001). At mean follow-up of 25 ± 11 months, 42% of patients had IART recurrence and 28% required cardioversion. Six deaths occurred (1.8%/patient-year), and two patients underwent transplant. Chronic outcomes were associated with higher right atrial saturations, use of electroanatomic mapping, fewer IART circuits encountered and acute procedural success. ConclusionsImprovement of acute RFCA outcomes was contemporaneous with introduction of novel technologies. Intra-atrial re-entrant tachycardia recurrence was common, and no effect on mortality was discerned, but most patients had effective palliation of symptoms. Chronic outcome predictors included the underlying disease severity, application of novel technologies and successful ablation of all targeted arrhythmia circuits.

Coexistence of type I atrial flutter and intra-atrial re-entrant tachycardia in patients with surgically corrected congenital heart disease

OBJECTIVES This study assessed the coexistence of intra-atrial re-entrant tachycardia (IART) and isthmus-dependent atrial flutter (IDAF) in patients presenting with supraventricular tachyarrhythmias after surgical correction of congenital heart disease (CHD). BACKGROUND In patients with CHD, atrial tachyarrhythmias may result from IART or IDAF. The frequency with which IART and IDAF coexist is not well defined. METHODS Both IDAF and IART were diagnosed in 16 consecutive patients using standard criteria and entrainment mapping. Seven patients had classic atrial flutter morphology on surface electrocardiogram (ECG), whereas nine had atypical morphology. RESULTS A total of 24 circuits were identified. Three patients had IDAF only, five had IART only, seven had both, and one had a low right atrial wall tachycardia that could not be entrained. Twenty-two different reentry circuits were ablated. Successful ablation was accomplished in 13 of 14 (93%) IART and 9 of 10 (90%) IDAF circuits. There was one IART recurrence. The slow conduction zone involved the region of the right atriotomy scar in 12 of 14 (86%) IART circuits. No procedural complications and no further recurrences were seen after a mean follow-up of 24 months. CONCLUSIONS Both IDAF and IART are the most common mechanisms of atrial re-entrant tachyarrhythmias in patients with surgically corrected CHD, and they frequently coexist. The surface ECG is a poor tool for identifying patients with coexistent arrhythmias. The majority of IART circuits involve the lateral right atrium and may be successfully ablated by creating a lesion extending to the inferior vena cava.

Electroanatomic characterization of conduction barriers in sinus/atrially paced rhythm and association with intra-atrial reentrant tachycardia circuits following congenital heart disease surgery.

The electrophysiologic mechanism of intra-atrial reentrant tachycardia (IART) is generally thought to be a macroreentrant circuit revolving around a nonconductive or highly anisotropic barrier. However, the electrical and anatomic substrate that supports these circuits has been incompletely defined. Our objectives were to characterize the atria of patients with IART using electroanatomic mapping in sinus or atrially paced rhythm and to determine whether electrical barriers identified in sinus/atrially paced rhythm are associated with IART circuits. Eighteen patients with IART and a remote history of repaired or palliated congenital heart disease were studied [8 biventricular repair, 8 single ventricle palliation (7 Fontan), and 2 Mustard repair]. Thirteen patients had a right AV valve. In sinus/atrially paced rhythm, electrical evidence of a crista terminalis was identified in 11 patients, an atriotomy in 12, and > or = 1 right atrial free-wall scar in 11. In 26 IART circuits characterized, 12 used the right AV valve as a central obstacle, 6 used a right atrial free-wall scar, 3 used an atriotomy, 3 used the crista terminalis, and 2 circuits used an atrial septal scar. All central obstacles used by IART circuits were identified in sinus/atrially paced rhythm. The crista terminalis, atriotomy, and right atrial scars can be identified in patients with repaired congenital heart disease by electroanatomic mapping in sinus/atrially paced rhythm. These conduction barriers frequently function as the central obstacle for IART. Demonstration of such features may help focus investigational mapping without reliance on spontaneous initiation of the tachycardia.

Location of acutely successful radiofrequency catheter ablation of intraatrial reentrant tachycardia in patients with congenital heart disease

Intraatrial reentrant tachycardia (IART) is common after surgery for congenital heart disease (CHD). Radiofrequency (RF) catheter ablation of IART targets anatomic areas critical to the maintenance of the arrhythmia circuit, areas that have not been well defined in this patient population. The purpose of this study was to determine the anatomic areas critical to IART circuits, defined by activation mapping and confirmed by an acutely successful RF ablation at the site. A total of 110 RF ablation procedures in 88 patients (median age 23.4 years, range 0.1 to 62.7) with CHD were reviewed. Patients were grouped according to surgical intervention: Mustard/Senning (n = 15), other biventricular repaired CHD (n = 24), Fontan (n = 43), and palliated CHD (n = 6). In first-time ablation procedures, ≥1 IART circuits were acutely terminated in 80% of Mustard/Senning, 71% of repaired CHD, and 72% of Fontan (p = NS). The palliated CHD group underwent 1 of 6 successful procedures (17%), and this patient was excluded. The locations of acutely successful RF applications in Mustard/Senning patients (n = 14 sites) were at the tricuspid valve isthmus (57%) and at the lateral right atrial wall (43%). In patients with repaired CHD (n = 18 sites), successful RF sites were at the isthmus (67%) and the lateral (22%) and anterior (11%) right atria. In the Fontan group (n = 40 sites), successful RF sites included the lateral right atrial wall (53%), the anterior right atrium (25%), the isthmus area (15%), and the atrial septum (7%). Location of success was statistically different for the Fontan group (p = .002). In conclusion, the tricuspid valve isthmus is a critical area for ablation of IART during the Mustard/Senning procedure and in patients with repaired CHD. IART circuits in Fontan patients are anatomically distinct, with the lateral right atrial wall being the more common area for successful RF applications. This information may guide RF and/or surgical ablation procedures in patients with CHD and IART.

Efficacy of Radiofrequency Ablation for Control of Intraatrial Reentrant Tachycardia in Patients With Congenital Heart Disease

Background. Intraatrial reentrant tachycardia (IART) is a common problem in patients with congenital heart disease (CHD). The progression of clinical symptoms of IART and their response to radiofrequency (RF) ablation are not yet well described.Objectives. The objective of the study was to determine the early and midterm success rates of RF ablation in effecting a reduction of clinical arrhythmic events in patients with IART and CHD.Methods. Clinical records of patients undergoing early, successful RF ablation were analyzed retrospectively to document the occurrence and frequency of documented IART, cardioversion and arrhythmia-related hospital visits before and after ablation.Results. Fifty-five catheterizations for intended RF ablation of IART were performed in 45 patients (mean [±SD] age 24.5 ± 10.5 years, 40 after surgical palliation of CHD). Early success was achieved for one or more IART circuits in 33 patients (73%). Mean clinical follow-up of those patients with successful ablation is 17.4 ± 11.3 months (total 574 patient-months). Documented IART recurrence was noted after 21 (53%) of 40 early, successful catheterizations in 17 (52%) of 33 patients, with a mean time to recurrence of 4.1 months, often with electrocardiographically novel configurations. A more prolonged and frequent history of IART was a univariate risk factor for recurrence. Seven patients underwent repeat RF ablations, and eight patients were restarted on antiarrhythmic medications after ablation. Two patients who had severe ventricular dysfunction before RF ablation died 1.5 and 11 months after RF ablation without known arrhythmia recurrence. Clinical events related to IART increased steadily in frequency for 24 months before RF ablation. Radiofrequency ablation resulted in a reduction of event frequency to levels significantly lower than those in the 12-month period before RF ablation and not significantly different from those levels observed at baseline 3 to 4 years before RF ablation.Conclusions. In patients with successful RF ablation, the frequency of subsequent events was reduced compared with the 2 preceding years. However, recurrence of IART in patients who showed clinical improvement was frequent, and often revealed the presence of new IART configurations.

Radiofrequency ablation of intra-atrial reentrant tachycardia after surgical palliation of congenital heart disease.

Intra-atrial reentrant tachycardia (IART), also called atrial flutter, is a common and potentially lethal complication of surgical correction of congenital heart disease. Medical management of IART is often problematic, which prompts an investigation of the utility of radiofrequency (RF) ablation for management of these arrhythmias. Ten consecutive patients referred for treatment of recurrent IART after surgery for congenital heart disease were studied. Median age was 18.4 years, and median duration of arrhythmia was 6.4 years; a median of three antiarrhythmic drugs had been tried. Surgical procedures used were Fontan (6), Mustard/Senning (2), and biventricular repair (2). Intracardiac electrophysiological study demonstrated 30 distinct IART circuits, defined by activation sequence and cycle length. Mean IART cycle length was 323 +/- 114 ms. Cycle length was significantly longer in IART circuits that were successfully ablated compared with those that were not (381 versus 248 ms, P < .001). RF ablation was attempted in 22 of these circuits. Ablation sites were targeted to presumed exit points from zones of slow conduction by electrophysiological criteria. Sites chosen in this manner clustered in four distinct areas of the right atrium. Of 22 IART circuit ablations attempted, 17 (77%) resulted in acute termination of the tachycardia. In 8 of 10 patients in whom at least one IART circuit was successfully ablated, 4 are free of clinical tachycardia and 3 are improved over short-term follow-up. No complications were encountered. Multiple IART circuits may be present in patients after surgery for congenital heart defects. Activation sequences observed were diverse and different from those observed in atrial flutter in patients with normal anatomy. Interruption of IART circuits by RF ablation is feasible using mapping techniques aimed at identifying an exit point from a zone of slow conduction. Short-term follow-up suggests that RF ablation may be a useful adjunct in management of IART in these difficult patients.