Intra-atrial Reentry Tachycardia Research Articles

Continuous monitoring with implantable loop recorder detects arrhythmic risk in adults with systemic right ventricle following atrial switch

Abstract Background Patients with a systemic right ventricular circulation following atrial switch are at high risk of sudden death despite current monitoring strategies and advances in heart failure management. Arrhythmia represents a significant risk factor and early detection and intervention is of great value. The current surveillance approach with intermittent ambulatory monitoring is limited and cumbersome. Purpose We hypothesise that continuous rhythm monitoring with an implantable loop recorder (ILR) in the systemic right ventricle population will allow early detection of clinically significant arrhythmias. Methods Patients under follow up with a systemic right ventricular circulation following atrial switch were offered ILR implantation as an alternative to the standard of care (ambulatory 24-hour ECG). Patients with pre-existing intra-cardiac pacing devices or palliative were excluded. Following implantation, recordings made with symptoms or automatically following detection of significant arrhythmias. This included pauses over 3 seconds, atrioventricular block or supraventricular tachycardia. Transmission were reviewed daily and significant findings discussed in an adult congenital heart disease and electrophysiology MDT. Patients otherwise had routine clinical care. Results 24 patients had implantation of a loop recorder (67% of eligible cohort). They were aged 29-49 years (median 35 years) and 50% had additional lesions. Right ventricular function was normal in 42% and 29% had moderate or severe tricuspid regurgitation. 75% of the cohort were NYHA classification I. All but one patient were in sinus rhythm and 8 (33%) had previous intra-atrial re-entry tachycardia (IART). No patient had previously documented significant conduction disease. Implants were undertaken over 6 years without complications. 18 patients (75%) had automated or symptom activated recordings (52% automated) with a median of 2.8 recordings per patient (range 0 – 8 per patient) over 39.5 months (1.6 – 72.5 months). The recordings were clinically significant in 64% of the cohort (Table). This included 2 (9% of entire cohort) patients with atrioventricular block only, 11 patients (46%) with IART only and 4 patients (17%) with both IART and conduction disease (1 with atrioventricular block). These recordings resulted in 5 pacemaker implants (3 for atrioventricular block) and 2 further patients declined a device (1 subsequent death). 4 patients underwent, or are awaiting, ablation for IART. Risk scoring for sudden death did not predict arrhythmia events or atrioventricular block (1) (Figure). Conclusions Empirical ILR implantation in this low-risk systemic right ventricle cohort was well tolerated and detected a high burden of significant arrhythmias requiring intervention. Arrythmias were not predicted by risk scoring. This monitoring approach is an effective alternative to intermittent ambulatory surveillance however the impact on sudden death is unclear.

Arrhythmias and Clinical Outcomes in a Swiss Multicenter Cohort of Patients With Dextro-Transposition of the Great Arteries and Atrial Switch.

Background Data on the incidence of arrhythmias, associated cardiac interventions, and outcome in patients with dextro-transposition of the great arteries and atrial switch are scarce. Methods and Results In this multicenter analysis, we included adult patients with dextro-transposition of the great arteries and atrial switch regularly followed up at 3 Swiss tertiary care hospitals. The primary outcome was a composite of left ventricular assist device, heart transplantation, and death. The secondary outcome was occurrence of ventricular tachycardia, ventricular fibrillation, or sudden cardiac death. We identified 207 patients (34% women; median age at last follow-up, 35 years) with dextro-transposition of the great arteries and atrial switch. Arrhythmias occurred in 97 patients (47%) at a median age of 22 years. A pacemaker or an implantable cardioverter-defibrillator was implanted in 39 (19%) and 13 (6%) patients, respectively, and 33 (16%) patients underwent a total of 51 ablation procedures to target 60 intra-atrial re-entry tachycardias, 4 atrioventricular nodal re-entry tachycardias, and 1 atrial fibrillation. The primary outcome occurred in 21 patients (10%), and the secondary outcome occurred in 18 patients (9%); both were more common in patients with concomitant ventricular septum defect than in those without (hazard ratio [HR], 3.06 [95% CI, 1.29-7.27], P=0.011; and HR, 3.62 [95% CI, 1.43-9.18], P=0.007, respectively). Conclusions In patients with dextro-transposition of the great arteries and atrial switch reaching adulthood, arrhythmias occur in almost half of patients, and associated rhythm interventions are frequent. One-tenth of those patients do not survive until the age of 35 years free from left ventricular assist device or heart transplantation, and the outcome is worse in patients with concomitant ventricular septum defect.

Comparison of the effects of conventional method and primary sutureless techniques on early postoperative rhythm problems in patients with total abnormal pulmonary venous return anomaly.

Total abnormal pulmonary venous return anomaly is a CHD characterised by abnormal pulmonary venous flow directed to the right atrium. In this study, we aimed to compare the effects of these techniques on early rhythm problems in total abnormal pulmonary venous return anomaly cases operated with conventional or primary sutureless techniques. Seventy consecutive cases (median age 1 month, median weight 4 kg) who underwent total abnormal pulmonary venous return anomaly repair with conventional or primary sutureless technique between May 1 2020 and May 1 2022 were evaluated. The rate, diagnosis, and possible risk factors of postoperative arrhythmias were investigated. The results were evaluated statistically. When the total abnormal pulmonary venous return anomaly subgroup of 70 cases was evaluated, 40 cases were supracardiac, 18 cases were infracardiac, 7 cases were cardiac, and 5 cases were mixed type. Twenty-eight (40%) cases had a pulmonary venous obstruction. Primary sutureless technique (57%, supracardiac n = 24, mixed = 3, infracardiac = 13) was used in 40 patients. Median cardiopulmonary bypass time (110 versus 95 minutes) and median aortic clamp time (70 versus 60 minutes), median peak lactate (4.7 versus 4.8 mmol/l) in the first 72 hours, and median peak vasoactive inotropic score in the first 72 hours of the primary sutureless and conventional technique used cases value (8 versus 10) were similar. The total incidence of arrhythmias in the conventional group was significantly higher than in the primary sutureless group (46.7% versus 22.5%, p = 0.04). Supraventricular early beat was observed in 3 (7.5%), sinus tachycardia was seen in 6 (15%), junctional ectopic tachycardia was seen in 1 (2.5%), intra-atrial reentry tachycardia was seen in 1 (2.5%), usual supraventricular tachyarrhythmia was seen in 2 cases (5%) in the primary sutureless group. In the conventional group, supraventricular early beat was observed in six of the cases (20%), sinus tachycardia in five (16.7%), junctional ectopic tachycardia in four (13.3%), intra-atrial reentry tachycardia (10%) in three, and supraventricular tachyarrhythmia in seven cases (23.3%). In the first 30 days, there was a similar mortality rate (10% versus 10%), with four patients in the primary sutureless group and three in the conventional group. The median follow-up period of the cases was 8 months (interquartile range(IQR) 6-10 months). In the follow-up, arrhythmias were detected in two cases (one supraventricular tachyarrhythmia and one intra-atrial reentry tachycardia) in the primary sutureless group and three cases (two supraventricular tachyarrhythmia, one intra-atrial reentry tachycardia) in the conventional technique. All cases were converted to normal sinus rhythm with cardioversion and combined antiarrhythmic therapy. Different arrhythmias can be observed in the early period in patients with operated total abnormal pulmonary venous return anomaly. Although a higher rate of rhythm problems was observed in the early period in the conventional method compared to the primary sutureless technique, no significant effect was found on mortality and morbidity between the groups.

Arrhythmia burden, rhythm interventions and outcome in a large Swiss multicenter population of d-TGA patients with atrial switch

Abstract Funding Acknowledgements Type of funding sources: None. Background Patients with dextro-transposition of the great arteries (d-TGA) and atrial switch face a high life-time risk of arrhythmias. Purpose To describe the incidence of arrhythmias, associated cardiac interventions and outcome in a large Swiss population of patients with d-TGA and atrial switch. Methods In this multicenter analysis we included all consecutive patients with d-TGA and atrial switch treated at three Swiss tertiary care hospitals. The primary outcome was survival free from left ventricular assist device (LVAD), heart transplantation (HTx) and death. The secondary outcome was survival free from ventricular tachycardia, ventricular fibrillation and sudden cardiac death. Results We identified 207 patients (34% females; median age at last follow-up 35 years) with d-TGA and atrial switch. Arrhythmias occurred in 97 patients (47%) at a median age of 22 years. A pacemaker or an implantable cardioverter/defibrillator was implanted in 39 (19%) and 13 (6%) patients, respectively, and 33 (16%) underwent a total of 51 ablation procedures to target 60 intra-atrial reentry tachycardias, 4 AV nodal reentry tachycardias and one atrial fibrillation (Figure 1). The primary outcome occurred in 21 patients (10%) and the secondary outcome in 18 (9%) (Figure 2). Primary and secondary outcomes were more common in patients with concomitant ventricular septum defect (VSD) than in those without (hazard ratio [HR] 3.06; 95% confidence interval [CI] 1.29-7.27, p=0.011; and HR 3.62; 95% CI 1.43-9.18, p=0.007, respectively). Conclusions At a median age of 35 years, arrhythmias occur in almost half of patients with d-TGA and atrial switch and associated rhythm interventions are frequent. One in ten patients does not survive free from LVAD and HTx and outcome is worse in patients with concomitant VSD.

P1007Efficacy and safety of atrial ablation procedures in patients with complete d-TGA and atrial switch at a Swiss tertiary center

Abstract Introduction Patients with complete transposition of the great arteries (d-TGA) and atrial switch face a high lifetime risk of arrhythmias. Interventions in these patients are challenging because of their particular anatomy. Reports on ablation procedures in this patient population are scarce and missing for Switzerland. Method We retrospectively analyzed all ablation procedures performed in the above-mentioned population at a Swiss tertiary care center. Results Among 73 d-TGA pts. (71% male; N=37 Senning; N=36 Mustard) followed at our center, 17 ablations were performed in 11 pts. (15%; one ablation in 8 pts., two in 2 pts. and five in 1 patient). Median age at first ablation was 34 years (range 15–49 years). A total of 17 different intra-atrial reentry tachycardias (IART) and 3 AVNRT were targeted. Of the IART, 10 were cavotricuspid isthmus (CTI)-dependent and 7 were not. In two procedures (12%) only the systemic venous (SV) baffle was accessed for ablation. In 15 procedures (88%), ablation was performed within the pulmonary venous (PV) baffle. Access to the PV baffle was retrograde via the aorta in 6 cases (35%), via a baffle leak in 3 (18%) and via baffle puncture in 6 (35%). All procedures with retrograde approach to the PV baffle or with SV baffle only ablation were performed up to January 2012 and all remaining procedures afterwards. The 3 pts. requiring repeat procedures had retrograde or SV baffle approaches initially, and one additional ablation via baffle puncture was successful. The CTI was targeted in 10 pts. (91%) and ablation was finally successful in all with bidirectional block demonstrated in 8 pts. The coronary sinus was found to drain into the SV baffle in 5 pts. (46%) and useful for assessment of CTI block. The seven CTI-independent IART were scar-related micro-reentries. Ablation of all 3 AVNRTs was successful after one procedure without recurrence. Slow pathway ablation was performed in the SV baffle in two and in the PV baffle in one case (Figure). After a median follow-up of 7 months (range 2–186 months) 9 pts. are without recurrence and in 2 pts. rare self-limited arrhythmias still occur. No procedural complications occurred. Conclusion Arrhythmias in patients with complete d-TGA and atrial switch are mainly CTI-dependent IART or scar-related micro-reentries, and a few patients also have AVNRT. Ablation of these arrhythmias is safe and successful if PV baffle access is achieved via a baffle leak or baffle puncture.

Usefulness of High-Dose Oral Flecainide for Termination of Recent-Onset Atrial Fibrillation in Children

A high dose of oral flecainide has been used for acute termination of atrial fibrillation (AF) and atrial flutter or intra-atrial re-entry tachycardia (AFL-IART) in adults. The use of flecainide for these conditions in children has not been well described. We describe our institutional experience on acute termination of AF or AFL-IART in children with a single high dose of oral flecainide in a hospital setting. All patients who received a single high dose of oral flecainide from 2009 to 2016 who were <21 years of age were included. Patients were treated only if AF or AFL-IART was less than 24 hours of duration. The dose was 300 mg for patients >70 kg, 200 mg for patients 40 to 70 kg, and 5 mg/kg for patients <40 kg. Charts were reviewed to determine demographic information, flecainide dose, termination of arrhythmia, and time to termination. There were 22 patients identified. The median age was 16 years (range 4.6 to 20.3) with a median weight of 75 kg (range 19 to 112). There were 13 patients with AF (11 with a normal heart, 85%) and 9 patients with AFL-IART (1 with a normal heart, 11%) (p <0.05). The median dose of flecainide given was 3.6 mg/kg (range 2.7 to 6.1) or 136 mg/m2 (range 90 to 171). AF in all patients (13/13, 100%) and AFL-IART in 5 of 9 patients (55%) terminated acutely (p <0.05). All patients with normal heart (12/12, 100%) and 6 of the 10 patients (60%) with heart disease have their arrhythmia terminated acutely (p <0.05). The only patients whose tachycardia did not terminate were 4 patients with IART and heart disease. The arrhythmia terminated in a median time of 60 minutes (range 30 to 120). There were no adverse events or proarrhythmia encountered. In conclusion, a single high dose of oral flecainide successfully terminated AF of less than 24 hours' duration in all pediatric patients without side effects. This approach is less effective for AFL-IART in patients with heart disease.

Radiofrequency catheter ablation in infants and children

Background: Diagnosis and treatment of paediatric arrhythmias remain challenging. Antiarrhythmic - drugs beta-blockers, class Ic and class III drugs, were the only treatment available for many years. Radiofrequency catheter ablation (RFCA) was introduced for adult patients in 1981 and has been used for children since 1989. Questions remain regarding the efficacy and safety in paediatrics. Method: A retrospective analysis of patient records, 12 years and younger, at Leuven University Hospital, from January 2011 - July 2015 was performed. Results: From January 2011 - July 2015, 51 ablations were performed in 44 patients ≤12 years of age. Mean age was 7 years (range 3 weeks - 12 years), 11 (21.5%) ≤2 years; mean weight 16.5kg (range 3.4 - 56kg); average screening time 33.5min (SD } 22.7). Echocardiography was normal in 32 (72.7%) of patients. All cases were done under general anaesthesia. Diagnosis at electrophysiological study: Atrioventricular reentry tachycardia in 26 (50.9%), atrial ectopic tachycardia in 7 (13.7%), intra-atrial reentry tachycardia in 5 (9.8%), atrioventricular nodal reentry tachycardia in 11 (21.6%) and ventricular tachycardia in 2 (3.9%). RFCA was successful in 44 (86.3%) with recurrence rate of 13.7%. No signifi cant complications were noted. Conclusion: RFCA can be performed safely and effectively in even the very young. Recurrence and complication rates are similar to those reported in adults. RFCA should be the treatment of choice in selected paediatric patients.

Arrhythmias Following the Mustard and Senning Operations for Dextro-Transposition of the Great Arteries: Clinical Aspects and Catheter Ablation.

The atrial switch operations, the Mustard and Senning procedures, performed for dextro-transposition of the great arteries, have largely been supplanted by the arterial switch operation. As such, affected patients will only exist for approximately 30 more years. The main arrhythmias in these patients include sinoatrial node dysfunction, intraatrial reentry tachycardia, and sudden death. Device therapy for these patients is well-established, and catheter ablation for atrial tachycardias is highly efficacious. The application of meticulous procedural planning, customization of catheter courses, and electrophysiologic principles to this patient group may be extended to all postoperative complex congenital heart patients.

Early to Midterm Results of Total Cavopulmonary Connection in Adult Patients

Total cavopulmonary connection (TCPC) has not been studied in adults. We investigated early and midterm morbidity and mortality in adults undergoing TCPC and assessed risk factors for mortality. Between June 1994 and October 2010, 30 adults (21.3 ± 5.5 years) underwent TCPC (extracardiac conduit). Twenty-two patients who had palliated single ventricles underwent TCPC completions and 8 patients underwent TCPC conversions. Preoperative and perioperative data were reviewed retrospectively. Six of 9 patients with preoperative atrial flutter or fibrillation or intraatrial reentry tachycardia were treated in the catheterization room. An aortic cross-clamp was necessary in 12 patients, and 16 TCPCs were fenestrated. Mean follow-up was 51 months (range, 4-198 months). Early mortality was 10%: 2 of 8 conversions and 1 of 22 completions. There was 1 late conversion death (at 56 months postoperatively). Postoperatively, 4 patients required pacemakers and 1 patient required long-term antiarrhythmic medication, but no heart transplantations were necessary. Risk factors for early mortality were arrhythmia (p = 0.02), aortic cross-clamp (p = 0.054), and extracorporeal circulation in hypothermia (p = 0.03). Risk factors for overall mortality were conversion (p = 0.047), absence of fenestration (p = 0.036), surgery before January 2006 (p = 0.036), aortic cross-clamp (p = 0.018), extracorporeal circulation in hypothermia (p = 0.008), and arrhythmia (p = 0.005). New York Heart Association functional class had improved at the last follow-up: preoperatively, 17 patients were in class II and 12 patients were in class III versus 18 patients in class I and 9 patients in class II postoperatively (p < 0.001). At the last clinical visit, systemic ventricular function was maintained, and no late supraventricular arrhythmia was found. Early and midterm TCPC results for adults are encouraging for completion but are disappointing for conversion. Identified risk factors for mortality should improve patient selection for TCPC.

Cardiac Electrical System Involvement in Alström Syndrome: Uncommon Causes of Dilated Cardiomyopathies

Alström syndrome is a rare autosomal recessive disorder with dilated cardiomyopathy in 60% of patients. Despite the frequency of cardiac involvement in Alström syndrome, conduction system abnormalities or arrhythmias have not been characterized previously. We report two siblings with Alström syndrome with conduction system involvement with left bundle branch block on electrocardiogram (ECG). One patient had first degree atrioventricular block in addition to bundle branch block and underwent pacemaker implantation. This same patient developed intra-atrial reentry tachycardia requiring anti-arrhythmic medication and eventual trans-catheter ablation. The second patient developed atrial and ventricular arrhythmias and underwent placement of a bi-ventricular defibrillator. These findings suggest that cardiac conduction system involvement and clinical arrhythmia may be significant yet under-recognized complications in patients with Alström syndrome. Patients should be routinely screened with ECG and Holter monitoring in addition to echocardiographic assessment and a cardiologist experienced with cardiomyopathy should be an integral part of the care team.

Catheter Ablation of Arrhythmias in Ebstein's Anomaly: A Multicenter Study

In patients with Ebstein's anomaly (EA) arrhythmias are frequently encountered. Although most arrhythmias can be targeted with catheter ablation, specific issues render the procedure more challenging in EA. This study examines the mechanisms of the different arrhythmias related to EA and the outcome after catheter ablation. Clinical and procedural data of catheter ablation in patients with EA in 4 European centers were analyzed. In 32 patients (mean age 24 ± 15 years), 34 accessory pathways (APs), 8 intra-atrial reentry tachycardias (IART), 5 cavotricuspid isthmus-dependent atrial flutter (CTI-AFL), 2 focal atrial tachycardias, and 1 atrioventricular nodal reentry tachycardia were ablated. In 11 patients (34%), multiple ablation targets were present. Eighteen patients (56%) required multiple procedures either for repeat ablation of the same arrhythmia (n = 12), ablation of a different arrhythmia (n = 4), or both re-ablation of the same and of a different arrhythmia (n = 2). Procedural success rate after first ablation was 80% for APs and CTI-AFL ablation, and 100% for IART ablation. Redo procedures were necessary in 40% of the patients after ablation of an APs, and in 60% after CTI-AFL ablation, but in none of the patient with IART ablation. Most arrhythmias related to EA are amenable to catheter ablation. However, ablation procedures are challenging and the need for repeat procedure is particularly high, because some patients have multiple ablation targets and because of technical issues in relation with the dysplastic tricuspid annulus. In addition, several patients develop other arrhythmia mechanisms following ablation.

Experience with CartoSound for arrhythmia ablation in pediatric and congenital heart disease patients

Electro-anatomic mapping (EAM) has been used for more than a decade to assist in defining arrhythmia propagation for transcatheter ablation. Intra-cardiac echocardiography (ICE) has also gained acceptance as an adjunct to further define intracardiac anatomy. The integration of these two technologies (CartoSound, Biosense-Webster, Diamond Bar, CA, USA) is a recent development. In this report, we describe our early experience in the young, with and without congenital heart defects (CHD). The clinical and electrophysiologic records of the first 17 patients to undergo procedures with the CartoSound (EAM-ICE) system were reviewed. In all 17, the 3-dimensional shape of the chamber(s) of interest was created using serial tracing of ICE images. The ICE catheter was placed in the esophagus in three and through the femoral vein in 14. Descriptive analysis was performed on demographic data as well as procedural characteristics including procedure time, fluoroscopy time, geometry acquisition time, EAM duration, ablation time, procedure success, and complications. Arrhythmias comprised intra-atrial re-entry tachycardia (13 patients, 76%), Wolff-Parkinson-White syndrome (1; 6%), ventricular ectopic tachycardia (2; 12%), and atrioventricular node re-entrant tachycardia (1; 6%). Thirteen had CHD, with a median two palliative operations; six had single-ventricle anatomy. Procedure duration was 266 ± 134min (median ± SD), and fluoroscopy time was 29 ± 28.3min. Geometry acquisition took 41 ± 35.4min, or 16% of the total case duration. Ablation lesions were placed in 16 cases, (cooled tip in 12) of which 15 (94%) were successful. One patient experienced mild hypotension. ICE image quality in three patients with the probe placed in the esophagus was suboptimal. Advantages of CartoSound appear to be (1) anatomy modeling in the shape imposed by the arrhythmia, (2) more accurate geometry than EAM alone, and (3) demonstration of catheter position and lesions on echo during the study. Perceived disadvantages are (1) the large sheath required for ICE (11F), and (2) significant procedure time devoted to creation of anatomy. Optimal use may be to focus on key structures required for ablation, obtaining additional views as needed.

Atrial Arrhythmias in Adult Patients With Right- Versus Left-Sided Congenital Heart Disease Anomalies

Atrial arrhythmias (AAs) are a common complication in adult patients with congenital heart disease. We sought to compare the lifetime prevalence of AAs in patients with right- versus left-sided congenital cardiac lesions and their effect on the prognosis. A congenital heart disease diagnosis was assigned using the International Disease Classification, Ninth Revision, diagnostic codes in the administrative databases of Quebec, from 1983 to 2005. Patients with AAs were those diagnosed with an International Disease Classification, Ninth Revision, code for atrial fibrillation or intra-atrial reentry tachycardia. To ensure that the diagnosis of AA was new, a washout period of 5 years after entry into the database was used, a period during which the patient could not have received an International Disease Classification, Ninth Revision, code for AA. The cumulative lifetime risk of AA was estimated using the Practical Incidence Estimators method. The hazard ratios (HRs) for mortality, morbidity, and cardiac interventions were compared between those with right- and left-sided lesions after adjustment for age, gender, disease severity, and cardiac risk factors. In a population of 71,467 patients, 7,756 adults developed AAs (isolated right-sided, 2,229; isolated left-sided, 1,725). The lifetime risk of developing AAs was significantly greater in patients with right- sided than in patients with left-sided lesions (61.0% vs 55.4%, p <0.001). The HR for mortality and the development of stroke or heart failure was similar in both groups (HR 0.96, 95% confidence interval [CI] 0.86 to 1.09; HR 0.94, 95% CI 0.80 to 1.09; and HR 1.10, 95% CI 0.98 to 1.23, respectively). However, the rates of cardiac catheterization (HR 0.63, 95% CI 0.55 to 0.72), cardiac surgery (HR 0.40, 95% CI 0.36 to 0.45), and arrhythmia surgery (HR 0.77, 95% CI 0.6 to 0.98) were significantly less for patients with right-sided lesions. In conclusion, patients with right-sided lesions had a greater lifetime burden of AAs. However, their morbidity and mortality were no less than those with left-sided lesions, although the rate of intervention was substantially different.

Pearls for Ablation in Congenital Heart Disease

Tachyarrhythmias occur in patients having congenital heart disease most commonly related to surgically created or naturally occurring conduction obstacles, and to postoperative hemodynamic effects on cardiac muscle. Less frequently, the underlying disease is associated with tachycardia substrates. Thorough knowledge of the patient's congenital anatomy and surgical procedures is required before considering catheter ablation. In many instances, procedural considerations should include meticulous hemodynamic surveillance, analogous to patients having structurally normal heart but cardiomyopathy. This includes careful selection of sedating and anesthetic agents. Congenital heart defects that have a higher than expected incidence of naturally occurring tachyarrhythmia substrates include Ebstein anomaly of the tricuspid valve, congenitally corrected transposition, and some of the heterotaxies. Intraatrial reentry tachycardia and atrial flutter are especially prevalent following the Mustard or Senning operations for d-transposition of the great arteries and the earlier Fontan type operations. Although these tachyarrhythmias are not as frequent following atrial septal defect repair, the high incidence of this defect also makes these patients germaine to this discussion. Focal atrial tachyacrdia and atrioventricular nodal reentry tachycardia also occur in these patient groups. Macroreentry ventricular tachycardia occurs most frequently following right ventricular outflow tract surgery, especially following repair of tetralogy of Fallot. This article focuses on the technical aspects of catheter ablation of these arrhythmias, due to the challenges presented by the underlying anatomy compared with patients having normal hearts.

Tachyarrhythmias after pediatric heart transplantation

Tachyarrhythmias in pediatric post-heart transplant patients are not well defined. In this study we sought to further characterize these arrhythmias in terms of presentation, course, and outcome. This investigation was a retrospective review of heart transplant recipients at St. Louis Children's Hospital during the period of 1991 to 2006. Patients were excluded if they were >18 years at transplantation or if follow-up information was unavailable. Patients with tachyarrhythmias beyond the first 2 weeks post-transplant were identified. Twenty-eight tachyarrhythmias occurred in 25 of 237 heart transplant recipients. Freedom from arrhythmia was 92% at 1-year post-transplant and 86% at 15 years post-transplant. Intra-atrial reentry tachycardia (12 patients) and ectopic atrial tachycardia (10 patients) were the most common arrhythmias. Rejection was found in 3 (12%) and previously unrecognized coronary disease was found in another 2 (8%) at the time of presentation with arrhythmia. Fifteen of 25 (60%) were asymptomatic at presentation, but 4 of 25 (16%) presented with heart failure, including 3 without evidence of rejection. No risk factors for developing arrhythmia were identified. Twenty-one arrhythmias resolved with brief pharmacologic or no therapy. Only 3 had a recurrence after the initial arrhythmia. Five patients underwent catheter ablation. Our experience suggests that the presence of tachyarrhythmias after pediatric heart transplantation is not rare and usually not associated with rejection. Pediatric heart transplant recipients have a higher incidence of ectopic atrial tachycardia (EAT) than their adult counterparts. Most tachyarrhythmias resolve after a relatively brief period of medical treatment and recurrence is uncommon.

Combined Atrial Septal Defect Surgical Closure and Irrigated Radiofrequency Ablation in Adult Patients

Atrial arrhythmias are relatively common among patients over 40 years old with atrial septal defect (ASD) and are a precipitating cause of heart failure. Surgical closure of the ASD in these patients is feasible and is associated with a low mortality rate and a beneficial effect on the clinical status; however the occurrence of atrial arrhythmia does not decrease after surgery. We present the results of our preliminary experience with surgical ASD closure combined with intraoperative irrigated radiofrequency (IRF) ablation in adult patients. During a 26-month period between September 2002 and December 2004, 15 patients more than 40 years old with ASD and atrial arrhythmia underwent elective surgical closure of the defect and intraoperative IRF ablation. All patients had supraventricular arrhythmias: 8 had permanent atrial fibrillation, whereas 7 had previous episodes of atrial flutter or intra-atrial reentry tachycardia. The biatrial approach (Cox-Maze III procedure) was used in 7 patients and a right-sided Maze procedure (ablation lines on the right atrium only) was carried out in the remaining 8 patients. All patients survived the procedure. Fourteen patients left the operating room in sinus rhythm and 1 had a pacemaker implanted. There were no complications resulting from the IRF ablation. All 15 patients survived over the average follow-up period of 24 months. Thirteen patients were still in sinus rhythm, 1 had pacemaker rhythm, and only 1 (1 of 15; 6.5%) suffered a recurrence of atrial fibrillation 3 months after the procedure. We suggest adding intraoperative IRF ablation during surgical closure of an ASD in all adult ASD patients with arrhythmias. The IRF ablation is easy to perform, safe, and effective.

Mapping and ablation of atypical flutter in congenital heart disease with a novel three-dimensional mapping system (Carto Merge®)

Mapping and successful ablation of an intra-atrial re-entry tachycardia in a patient after Fontan operation were performed within the anatomy, superimposed from the computed tomography study. In this case, the new system enabled us to display the complex anatomy of the right atrium in detail, whereas the conventional electro-anatomic three-dimensional geometry showed significant inconsistencies.

Improved early results with the Fontan operation in adults with functional single ventricle

Background A growing number of adults with functional single ventricles are presenting as candidates for first-time and redo-Fontan operations. This study describes the clinical presentation and early operative results of adults who have undergone Fontan modifications. Methods Between July 1995 and April 2003, 23 patients (>18 years old) had Fontan operations. We retrospectively reviewed their perioperative courses. Results Twenty-three Fontan operations (first-time [n = 8] and redo [n = 15]) were performed with no early or late deaths. No patient has required reoperation. One patient has been listed for orthotopic heart transplantation. The overall mean age is 23 years (18 to 41 years); mean follow-up, 30 months; median postoperative hospital stay, 8 days (4 to 34 days); and median duration of chest tube drainage, 4 days (2 to 12 days). The postoperative New York Heart Association (NYHA) functional class was improved in 22 of 23 patients. Eight first-time Fontan operations (7 of 8 nonfenestrated) were performed; lateral tunnel (n = 7) and extracardiac conduit (n = 1). Two patients had preoperative arrhythmias. New onset arrhythmias (ventricular tachycardia and sinus node dysfunction), requiring treatment, occurred in two patients. Fifteen redo-Fontan operations (all nonfenestrated) were performed; lateral tunnel (n = 5) and extracardiac conduit (n = 10). Fifteen patients had preoperative arrhythmias, thirteen of which had intraatrial reentry tachycardia (IART) and required antiarrhythmic medications. Concomitant intraoperative radiofrequency ablation (RFA) (n = 11) and cryoablation (n = 1) procedures were performed. In the immediate postoperative period, there was IART recurrence in five patients (post-RFA [n = 4] and postcryoablation [n = 1]). At latest follow-up, no patient is being treated with antiarrhythmic medications. Two patients had new onset atrial arrhythmias that required treatment. Conclusions The Fontan operation can be performed in adults with minimal morbidity and improved NYHA functional class. New onset arrhythmias requiring treatment are sources of perioperative morbidity. Complete arrhythmia resolution of the preoperative arrhythmia may not be achieved in the immediate postoperative period in redo-Fontan patients. However, modification (intraoperative radiofrequency ablation-right atrial debulking) of the atrial tachycardia circuits in the redo-Fontan patients can result in complete resolution of preoperative atrial tachyarrhythmias at early follow-up.

Frequency of late recurrence of intra-atrial reentry tachycardia after radiofrequency catheter ablation in patients with congenital heart disease

Forty-seven catheter ablation procedures for intra-atrial reentry tachycardia were performed in 40 patients with palliated congenital heart disease. The acute success rate was 87% and the recurrence rate was 34% during an average follow-up of 36 months. Of those patients who had recurrence, 88% did so within 1 year of ablation. Of the 23 patients who were free of recurrence 1 year after ablation, 21 (91%) remain free from recurrence at an average of 45 months (median 39; range 15 to 88) after ablation.

Outcome of symptomatic patients undergoing extracardiac Fontan conversion and cryoablation

Objective We review our experience with Fontan conversion and cryoablation in patients with an atriopulmonary Fontan in low cardiac output from arrhythmia or venous obstruction, including 2 patients with protein-losing enteropathy. Methods Ten patients (mean age 21.1 ± 7.0 years) underwent extracardiac Fontan conversion, cryoablation, and pacemaker placement between November 1999 and April 2002 (13.1 ± 4.1 years after the original atriopulmonary connection). Eight patients were in New York Heart Association class III and 2 were in New York Heart Association class IV. Nine patients had clinically important intra-atrial reentry tachycardia refractory to medical therapy. Results Follow-up was between 3.1 and 32.6 months (16.8 ± 9). One death occurred at 7 days after surgery due to sepsis and multisystem organ failure. The second death occurred at 48 days from complications of protein-losing enteropathy. The second patient with protein-losing enteropathy had improved New York Heart Association classification, cessation of albumin transfusions, and a normal stool alpha antitrypsin level (down from 4.1 mg/g preoperatively). Five patients improved to New York Heart Association class I and 3 patients to New York Heart Association class II. Sustained arrhythmias could not be induced in any patient. Seven patients are on no antiarrhythmics. One patient had recurrence of intra-atrial reentrant tachycardia 11 months postoperatively, which required electrical cardioversion; this patient’s symptoms are currently well controlled on 1 medication. Conclusion Extracardiac Fontan, cryoablation, and pacemaker placement reduced atrial arrhythmias and improved New York Heart Association classification in all surviving patients. In selected patients, this operation offers improvement in clinical outcome and is an alternative to transplantation. Protein-losing enteropathy may not be a contraindication to performing Fontan conversion with cryoablation.