Atrial arrhythmias in adults after repair of tetralogy of Fallot. Correlations with clinical, exercise, and echocardiographic findings

The significance of P wave duration and P wave dispersion for risk assessment of atrial tachyarrhythmias in patients with corrected tetralogy of Fallot

BACKGROUND

The aim of the present study was to determine the potential role of P wave duration and P wave dispersion for risk assessment of atrial tachyarrhythmias in patients with corrected tetralogy of Fallot (ToF).

METHODS

The maximum P wave duration, minimum P wave duration, and the P wave dispersion from the 12-lead surface electrocardiogram of the patients and controls were measured. Electrophysiological study was performed only in the patient group.

RESULTS

The study group consisted of 25 patients with corrected ToF with a mean age of 16.4 +/- 4.25 years and 25 age-matched healthy control subjects. Patients underwent repair at a mean age of 4.6 +/- 3.41 years (range: 1-19), and the mean duration of follow-up of 11.8 +/- 1.7 years (range: 9-15) after surgery. On electrophysiological study sinus node dysfunction was detected in 3 patients (12%), atrial tachyarrythmias-atrial flutter or fibrillation-in 5 patients (20%), both sinus node dysfunction and atrial flutter in 1 patient (4%), and AV conduction delay in 1 patient (4%). P wave dispersion is significantly higher in patients with atrial tachyarrhythmia inducible by electrophysiological study than in other patients (P < 0.05). A P wave dispersion value of >35 ms has a high predictive accuracy (sensitivity = 83% and specificity = 89%) for inducible atrial tachyarrhythmia in patients with corrected tetralogy of Fallot.

CONCLUSION

P wave dispersion is an easily measured electrocardiographic marker with a good sensitivity and specificity for predicting atrial arrhythmias in patients after correction of ToF.

Timing and type of surgery for severe pulmonary regurgitation after repair of tetralogy of Fallot

Repaired tetralogy of Fallot (rTOF) has an excellent long-term prognosis; however, survival is somewhat less than normal. Of all the residual lesions and sequellae after rTOF, pulmonary regurgitation (PR) is the most important, correlating with right ventricular (RV) size, exercise intolerance and serious ventricular arrhythmias. Pulmonary valve replacement (PVR) has beneficial effects on RV size and function, provided it is performed early, before irreversible RV dysfunction ensues. Moreover, PVR is associated with an improvement in patients' symptoms and exercise tolerance and combined with arrhythmia surgery (cryoablation) it leads to a dramatic decrease in the incidence of fatal ventricular arrhythmias. Associated lesions, especially branch pulmonary artery stenosis, which aggravates PR, and tricuspid regurgitation, which further impacts on RV size and function, need addressing. Large right ventricular outflow (RVOT) akinetic and aneurysmal regions are frequent and further compromise RV function; therefore, resection during PVR should be attempted. Despite excellent mid-term results, homografts and xenografts, usually used for RVOT reconstruction, suffer late dysfunction and failure, committing patients and surgeons to further operations. Therefore, the decision to operate should be based on the balance between progressive RV dilatation, exercise intolerance, symptoms, arrhythmias and the fact that further reoperations will be needed. Research on the ideal valve for RVOT reconstruction is ongoing. Prospective follow-up of patients with rTOF with exercise testing and assessment of RV size and function, preferably with magnetic resonance, will define better the natural history of the disease and will probably provide firm guidelines for PVR timing especially in asymptomatic patients.

Surgery for arrhythmias in children

BACKGROUND

Transcatheter radiofrequency ablation to treat supraventricular and ventricular arrhythmias has supplanted routine surgical ablative therapy and redefined its role. A small population of arrhythmia patients now requires surgical ablation: those who have failed catheter ablation, patients with concomitant congenital heart disease in association with arrhythmias, those with atrial fibrillation and very young patients for whom transcatheter techniques are prohibitive because of small size, cyanosis or distorted anatomy.

METHODS

From July 1992 through August 2003, 133 patients underwent arrhythmia surgery at Children's Memorial Hospital, 50% (67/133) in association with Fontan conversion (FC), 22% (28/133) with concomitant initial Fontan (IF) procedure and 28% (38/133) for various arrhythmias (MISC) in patients with (36/38, 95%) or without (2/38, 5%) associated structural heart disease. Mean age at surgery in the FC group was 20+/-7.6 years (median 19 years), and in the IF group and the MISC group, mean ages were 8.1+/-8.9 (median 4.2) years and 16.4+/-10.9 (median 11.3) years, respectively.

RESULTS

There were three operative (3/133, 2.6%; 1 FC, 2 MISC) and three late deaths (2 FC, 1 MISC). Four patients in the FC group had progressive ventricular failure and underwent successful cardiac transplantation. Follow-up data are available for non-transplant, surviving patients and reveal 11 incidences of persistent arrhythmia recurrence and 2 new-onset arrhythmias. Five of the 11 recurrences occurred early in our series of FC patients, when isthmus block interruption of arrhythmia foci was performed. Four additional recurrences occurred later in the FC series, two post-maze and two post-Cox-maze III. In the MISC group, there were two recurrences. Atrial reentry tachycardia (ART) recurred in a patient with no structural heart disease and accessory connection-mediated tachycardia recurred in a child who underwent concomitant initial Fontan. Two patients had ventricular tachycardia inducible at postoperative studies (2/7, 29%), but no clinical recurrence. Two new-onset tachycardias occurred, one child developed ART post-surgical ablation of accessory connections and one patient with inducible ventricular tachycardia developed ART 5 years postoperatively.

CONCLUSION

Variations in atrial and ventricular anatomy that may limit the catheter approach can be addressed surgically. Patient size or anatomic complexity should not be limiting factors in the combined surgical arrhythmia approach. Incorporation of arrhythmia therapy into planned surgical revision should be considered.

Medical therapy for sudden death

Drug therapy can reduce the incidence of sudden death in many subgroups of patients. Patients who have long QT syndrome, in particular, benefit significantly from the use of beta-blockers and other antiarrhythmic agents. Although less useful, drug therapy has an important adjunctive role in patients who have conditions, such as hypertrophic cardiomyopathy and congestive heart failure. Proarrhythmia, which is a potentially dangerous side effect of drug therapy, needs to be watched for with special care in this group of high-risk patients.

High energy external cardioversion for refractory atrial fibrillation in postoperative tetralogy of fallot

Long-term complications of surgical repair of Tetralogy of Fallot include atrial arrhythmias. These can be difficult to treat, and loss of sinus rhythm can lead to profound hemodynamic consequences in the presence of residual structural abnormalities. We describe the first report of high-energy external cardioversion in a 46-year-old man with repaired tetralogy of Fallot with atrial fibrillation refractory to conversion with normal energy. This represents an alternative to internal cardioversion or rate control for these patients.

Predicting late sudden death from ventricular arrhythmia in adults following surgical repair of tetralogy of Fallot

Tetralogy of Fallot was the first complex congenital cardiac defect to undergo open repair. The life expectancy and quality of life of those surviving surgery is now good, although late survival is compromised by the occurrence of sudden death. The emergence of successful methods for both the prevention of arrhythmias (including valve replacements and electrophysiological ablation) and the treatment of arrhythmias when they occur (including implantable defibrillators), has meant the identification of those at risk is of even greater importance. This paper reviews the predictive methods currently available to the practising physician caring for these increasingly common patients.

Clinical update on adults with congenital heart disease

The number of patients with congenital cardiac disease reaching adulthood is increasing steadily. Many adults with such disease face both medical and surgical difficulties. Most clinicians know very little about basic cardiac defects, their natural history, complications after surgery, and adequate management of these patients. We aim to provide an overview of the most frequently encountered cardiac lesions and long-term complications and to outline an up-to-date approach to their management. We present a series of hypothetical cases and discuss their management.

Efficacy of atrial antitachycardia pacing using the Medtronic AT500 pacemaker in patients with congenital heart disease

Patients with congenital heart disease are vulnerable to atrial tachyarrhythmias, especially after atrial surgeries. We evaluated the efficacy of atrial arrhythmia detection and antitachycardia pacing (ATP) using the Medtronic AT500 pacemaker in 28 patients with congenital heart disease (age 30 +/- 18 years). Of 15 patients with atrial arrhythmias, 14 had atrial tachycardia events that were appropriately detected. ATP was enabled for 167 treatable episodes, successfully converting 90 (54%). Rhythms classified as ventricular tachycardia were detected 127 times, yet most were actually atrial or sinus tachycardia with 1:1 atrioventricular conduction. Atrial tachycardias in congenital heart disease are amenable to ATP algorithms in the AT500 pacemaker.

Beyond Fontan conversion: Surgical therapy of arrhythmias including patients with associated complex congenital heart disease

BACKGROUND

Arrhythmia operations may be extended to patients with failed ablation procedures or associated structural defects requiring surgical intervention. The purpose of this study is to review our experience with arrhythmia operations in 29 patients who did not have Fontan conversions after the introduction of catheter ablation.

METHODS

Between July 1992 and January 2002, 29 patients had operations for refractory atrial (n = 24) or ventricular (n = 5) arrhythmias. Mechanisms of arrhythmia included atrial reentry (n = 11), atrial fibrillation (n = 5), automatic atrial (n = 3), accessory connections (n = 6), atrioventricular nodal reentry (n = 2), and ventricular tachycardia (n = 5). Median age at operation was 12.3 years (range, 6 days to 45 years). Two patients had structurally normal hearts; the remaining 27 patients underwent concomitant repair of structural heart disease, including atrioventricular valve replacement or repair (n = 8), anatomy-specific repair of Ebstein's anomaly (n = 4), tetralogy of Fallot repair or revision (n = 4), atrial septal defect closure (n = 3), ventricular septal defect repair (n = 2), Mustard takedown with arterial switch (n = 2), initial Fontan (n = 2), right ventricle-to-pulmonary artery conduit revision (n = 2), Norwood procedure (n = 1), 1 ventricular repair for Uhl's anomaly (n = 1), Mustard baffle revision (n = 1), pulmonary valve replacement with aneurysm resection (n = 1), and aortic valve replacement with complex repair (n = 1).

RESULTS

No patient developed heart block, and the surgical mortality rate was 7%. One patient died after Mustard takedown and arterial switch operation, and 1 neonate died after repair of severe Ebstein's anomaly. There was one late death after arterial switch conversion at another institution. Recurrent clinical supraventricular tachycardia was present in 2 patients (2 of 27, 7.4%) and 2 patients had new-onset tachycardias with different underlying mechanisms of arrhythmia at late follow-up (median follow-up 47 months).

CONCLUSIONS

Successful surgical therapy of arrhythmias can be performed safely at the time of repair of complex congenital heart disease or in patients with failed catheter ablation procedures. Early consideration for single-stage therapy of arrhythmia and structural heart disease is indicated.

Detecting and diagnosing arrhythmias in adults with congenital heart disease

Arrhythmias are a major cause of morbidity and mortality in adults with congenital heart disease; they can range from occult asymptomatic sinus node disease to sudden death. Detecting and diagnosing these arrhythmias presents a challenge when caring for these patients. A high index of suspicion is necessary, as well as a thorough understanding of the underlying heart defect and subsequent surgical interventions. A careful history, noninvasive evaluation, and in some cases invasive testing are all necessary to determine arrhythmias in this population.

Pericaval and periannular intra-atrial reentrant tachycardias in patients with congenital heart disease

INTRODUCTION

Intra-atrial reentrant tachycardia (IART) is a frequent late sequel of congenital heart surgery, often involving the cavotricuspid isthmus. In this report, we characterize pericaval reentry, a novel mechanism of isthmus-dependent IART in congenital heart patients, and compare its electrophysiologic characteristics with periannular atrial flutter.

METHODS AND RESULTS

Electrophysiologic and electroanatomic mapping data and acute outcomes were reviewed in postoperative patients with congenital heart disease who underwent electrophysiologic study/radiofrequency catheter ablation at The Children's Hospital, Boston between January 1999 and November 2000. The study included all congenital heart patients with IART and who had undergone (1) the Fontan procedure and (2) a biventricular surgical repair other than atrial switch procedures. Thirty-seven IARTs were mapped in 22 Fontan patients. Twelve of 37 IARTs (33%) that revolved about the inferior vena cava (IVC) and involved the isthmus between the IVC and the tricuspid dimple/right-sided AV valve were identified in 12 patients (48%). Mean pericaval IART cycle length was 332 +/- 60 msec (range 240-410). An adjacent or surrounding area of scarring was observed in 10 of 12 IARTs. Slow zones (mean activation latency 39% +/- 11% IART cycle length) were detected in 8 of 12 circuits. The boundaries of the zone of slow conduction were scar-low crista (6) and scar-IVC (2). Periannular IART with CL 289 +/- 65 ms was observed in 14 of 20 patients with 4-chambered hearts. Slow zones (mean activation latency 28 +/- 9% IART cycle length) were found in 8 of 14 circuits. In both forms of IART, the predominant direction of activation of the isthmus was lateral to septal; 83% in pericaval IART and 87% in periannular IART. Radiofrequency catheter ablation successfully terminated 11 of 11 pericaval and 13 of 14 periannular IARTs.

CONCLUSION

Pericaval reentry is a novel and ablatable mechanism of IART in patients specific to the Fontan procedure. It is distinguished from periannular atrial reentry by its association with Fontan anatomy, longer cycle lengths, and occurrence of a prominent discrete zone(s) of slow conduction. Both pericaval and periannular reentry show a marked preference for utilization of the isthmus in a lateral-to-septal direction.

Right ventricular function in adults with repaired tetralogy of Fallot assessed with cardiovascular magnetic resonance imaging: detrimental role of right ventricular outflow aneurysms or akinesia and adverse right-to-left ventricular interaction

OBJECTIVES

We examined the relationship among biventricular hemodynamics, pulmonary regurgitant fraction (PRF), right ventricular outflow tract (RVOT) aneurysm or akinesia, and baseline and surgical characteristics in adults with repaired tetralogy of Fallot (rTOF).

BACKGROUND

The precise relationship of pulmonary regurgitation with biventricular hemodynamics has been hampered by limitations of right ventricular (RV) imaging.

METHODS

We assessed 85 consecutive adults with rTOF and 26 matched healthy controls using cardiovascular magnetic resonance imaging.

RESULTS

Patients had higher right ventricular end-diastolic volume index (RVEDVi) (p < 0.001), right ventricular end-systolic volume index (RVESVi) (p < 0.001), right ventricular mass index (RVMi) (p < 0.001), and lower right ventricular ejection fraction (RVEF) (p < 0.001) and left ventricular ejection fraction (LVEF) (p = 0.002) compared to controls. The PRF (range 0% to 55%) independently predicted RVEDVi (p < 0.01) and the latter predicted RVESVi (p < 0.01) and RVMi (p < 0.01). The RVOT aneurysm/akinesia was present in 48/85 (56.9%) of patients and predicted RV volumes (RVEDVi, p = 0.01, and RVESVi, p = 0.03). There was a negative effect of RVOT aneurysm/akinesia and RVMi on RVEF (p < 0.01 and p = 0.02, respectively). There was only a tendency among patients with transannular or RVOT patching toward RVOT aneurysm/akinesia (p = 0.09). The LVEF correlated with RVEF (r = 0.67, p < 0.001).

CONCLUSIONS

Pulmonary regurgitation and RVOT aneurysm/akinesia were independently associated with RV dilation and the latter with RV hypertrophy late after rTOF. The RVOT aneurysm/akinesia was common but related only in part to RVOT or transannular patching. Both RV hypertrophy and RVOT aneurysm/akinesia were associated with lower RVEF. Left ventricular systolic dysfunction correlated with RV dysfunction, suggesting an unfavorable ventricular-ventricular interaction. Measures to maintain or restore pulmonary valve function and avoid RVOT aneurysm/akinesia are mandatory for preserving biventricular function late after rTOF.

Late problems in tetralogy of Fallot--recognition, management, and prevention

Most adults with previous repair of tetralogy of Fallot lead unrestricted lives and are asymptomatic. Residual RVOT problems such as significant PR and/or RVOT obstruction however are common and often lead to gradual RV dilation and dysfunction with consequent supraventricular or ventricular arrhythmias. Hemodynamic causes for the tachyarrhythmia should be sought and corrected, and therapy directed towards suppressing the arrhythmia (antiarrhythmics, cryoablation or AICD) should be carried out as well. Recent changes in the surgical approaches to the repair of tetralogy at the time initial repair may well translate into a reduced incidence of late complications.

Atrial arrhythmias in congenital heart disease

Surgical scars, volume overload and pressure overload are the three main determinants of atrial arrhythmias in patients with prior congenital heart surgery. The workup should include a thorough hemodynamic assessment. Treatment modalities available include drugs, pacemakers, catheter ablation and surgery. Despite the above, arrhythmias have a significant negative impact on life expectancy and quality in these patients. Newer surgical strategies for repair of the heart defect may delay or prevent the development of arrhythmias and are being actively pursued.

The role of the atria in congenital heart disease

The atria play an important role in adult congenital heart disease. Atrial function is often altered due to longstanding pressure or volume overload. Cardiac surgery inflicts lasting damage to the atria, which leads to loss of atrial compliance. Both the history of atrial overload and the atrial scarring form substrates for atrial tachycardias. There has been a growing interest in the interatrial septum in the past few years. There is evidence for a role of the persisting foramen ovale and atrial septal aneurysm as a causative or permissive factor in cerebral stroke. Catheter closure of the PFO may be an attractive option, especially for younger patients.

Influence of early repair of tetralogy of fallot without an outflow patch on late arrhythmias and sudden death: a 27-year follow-up study following a uniform surgical approach

Pulmonary regurgitation and older age at the time of repair may have a large impact late after repair on subsequent mortality of patients with tetralogy of Fallot. We aimed to identify whether age at repair, and preservation of the pulmonary valve, had a favorable influence on morbidity and mortality. We also analyzed risk factors for late death subsequent to surgical repair. We identified 167 patients who, between 1965 and 1975, and at a mean age of 6 years, underwent total repair of tetralogy of Fallot by a single surgical team without use of an outflow patch. All patients were known to have survived for at least 30 days after repair, and late mortality was identified though the use of hospital records, interviews, and death certificates. The 29-year actuarial survival rate was 86%, with 24 late deaths. Of these deaths, seven occurred suddenly (4.2%). Morbidity was analyzed in 99 of the patients by means of a written questionnaire and telephone interview. It proved possible to analyze ventricular and valvar function in 50 of the patients. Survivors experienced no re-intervention, and 89% of them were in class I of the grading system of the New York Heart Association. We found evidence of 3 episodes of sustained ventricular tachycardia (3.0%), and two episodes of atrial tachycardia (2.0%). Of the 50 patients in whom serial examinations were available, 18 had pulmonary regurgitation of moderate degree or greater, and none had more than moderate tricuspid regurgitation, with a mean QRS duration of 148 ms and an ejection fraction for the left ventricle of 50%. Older age at repair (p = 0.03), and longer periods of cardiac arrest during repair (p = 0.02), were associated with late mortality. Although the mortality was similar to that observed in previous reports, our operative method might have a better effect in terms of late morbidity.

Tetralogy of Fallot: Late outcome after repair and surgical implications

Cardiac surgery has transformed the outcome for patients with tetralogy of Fallot. Repair has conveyed excellent long-term results with most patients remaining well and leading normal lives. However, there are problems with late morbidity and mortality primarily due to right ventricular dysfunction, exercise intolerance, arrythmia, and sudden cardiac death. There has been a dynamic shift in our surgical approach to managing patients with tetralogy over the past 5 decades. This in part accounts for persisting difficulties in predicting late outcome for evry single patient with repaired tetralogy of Fallot. There are, however, several confounding variables, influencing long-term outcome for these patients, namely the underlying anatomical substrate, age at repair, surgical approach to repair, and residual hemodynamic abnormalities. It is gratifying to see that recent knowledge accumulated from long-term follow-up studies is influencing contemporary surgical practice. Individualized strategies aiming to minimize the potential for free pulmonary regurgitation, and the long-term detrimental effects associated with it, need to continue to develop. Preservation of right ventricular and pulmonary valve function combined with early restoration of normal pulmonary blood flow are likely to convey an even better long-term outlook for these patients. Further follow-up studies with assessment of bi-venticular function, however, are needed in both our older and contemporary cohorts with repaired tetralogy of Fallot. Copyright 2000 by W.B. Saunders Company

Sustained atrial arrhythmias in adults late after repair of tetralogy of fallot

We determined the prevalence of sustained atrial tachyarrhythmia (AT) in adults late after repair of tetralogy of Fallot (ToF) and examined its impact on subsequent heart failure, reoperation, and mortality. Ventricular arrhythmias are associated with increased morbidity and mortality in patients with repair of ToF. The clinical impact of AT in this population has not been established. A retrospective cohort study of 242 patients with repaired ToF identified 29 patients (prevalence of 12%) with sustained episodes of AT. Patients with repaired ToF but without sustained arrhythmia (n = 213) constituted a comparison group. Baseline characteristics and clinical outcomes in the 2 groups were compared. An echocardiographic analysis compared 15 patients with AT and 15 matched for age at operation and timing of echocardiography. The development of AT was associated with substantial morbidity including congestive heart failure, reoperation, subsequent ventricular tachycardia, stroke, and death (combined events, 20 of 29 patients [69%]). The rate of combined events (congestive heart failure, stroke, and deaths) in the 213 "arrhythmia-free" patients was 30% (64 of 213 patients). Event-free survival after repair was 18 +/- 2 years for the AT group and 28 +/- 1 years for the arrhythmia-free group (p < 0.001). Patients with AT were older at surgical repair (25 +/- 16 vs 10 +/- 9 years, p = 0.001), and at most recent assessment were aged 48 +/- 12 vs 32 +/- 10 years (p = 0.001). The AT group had a higher mean right atrial volume and proportion of significant pulmonary regurgitation than matched controls. The development of AT in the adult late after ToF repair identifies patients at risk and is associated with older age at repair, a higher frequency of hemodynamic abnormalities, and increased morbidity.

Risk factors for arrhythmia and sudden cardiac death late after repair of tetralogy of Fallot: a multicentre study

BACKGROUND

Ventricular arrhythmia and sudden cardiac death late after repair of tetralogy of Fallot are devastating complications in adult survivors of early surgery, but their prediction remains difficult.

METHODS

We examined surgical, electrocardiographic, and late haemodynamic data, and their relation to clinical arrhythmia and sudden death occurring over 10 years, in a multicentre cohort of patients with repaired tetralogy, who were alive in 1985.

RESULTS

Of 793 patients (mean age at repair 8.2 years [SD 8], mean time from repair 21.1 years [8.7]) who entered the study, 33 patients developed sustained monomorphic ventricular tachycardia, 16 died suddenly, and 29 had new-onset sustained atrial flutter or fibrillation. Electrocardiographic markers (QRS duration, QRS rate of change between 1985 and 1995) were significantly greater in the ventricular tachycardia and sudden-death groups. Older age at repair was associated with a higher risk of sudden death and atrial tachyarrhythmia. Pulmonary regurgitation was the main underlying haemodynamic lesion for patients with ventricular tachycardia and sudden death, whereas tricuspid regurgitation was for those with atrial flutter/fibrillation. Despite adverse haemodynamics, no patient who died suddenly had undergone late reoperation.

CONCLUSION

Arrhythmia and sudden death are important late sequelae for patients after repair of tetralogy of Fallot. The electrophysiological and haemodynamic substrate of sudden death resembled that of sustained ventricular tachycardia, with pulmonary regurgitation being the predominant haemodynamic lesion. Preservation or restoration of pulmonary valve function may thus reduce the risk of sudden death. Furthermore, electrocardiographic markers can help to identify patients at risk.

Atrial flutter in grown-up congenital heart (GUCH) patients. Clinical characteristics of affected population

OBJECTIVE

To define occurrence, lesions and clinical characteristics of grown-up congenital heart (GUCH) patients who develop atrial flutter (AFL).

DESIGN

All GUCH patients who presented as inpatients or outpatients with documented sustained AFL between 1996 and 1998 were studied prospectively. Retrospective review of case notes for basic data relating to underlying anomaly, prior surgery and age at onset of AFL, enquiry into events before the first attack. Clinical state was assessed by Ability Index before AFL and at last visit.

SETTING

Designated quaternary service for GUC in a tertiary referral centre.

RESULTS

From October 1996 to April 1998, 100 consecutive patients (49 female) aged 17-77 (mean 35) years, who presented to the GUCH Unit at Royal Brompton Hospital with a sustained attack of AEL documented by a 12 lead electrocardiogram were studied. Four basic cardiac anomalies accounted for 75% patients: one ventricle (26), atrial septal defect (ASD) (19), transposition of great arteries (TGA) (17) and Tetralogy of Fallot (13). AFL occurred occasionally in small ventricular septal defect (VSD), congenital corrected TGA (CC-TGA), pulmonary stenosis and pulmonary atresia with or without VSD. 86/100 patients had undergone cardiac surgery: Fontan 19 (22%), reconstruction of right ventricular outflow tract 17 (20%), closure of ASD 15 (17%), Mustard for TGA 13 (15%), and other palliative surgery 22 (26%). AFL occurred in 'natural history' (unoperated) in 14 (14%) mostly in CC-TGA, ASD and Fallot. Age at first attack was 6-64 (mean 28) years with the first attack occurring at younger age after Mustard (22+/-7 years) and Fontan (24+/-7), than in un-operated ASD (46+/-13) and CCTGA (31+/-10). Haemodynamic abnormalities from anatomical causes were present in 62/74 (84%) patients who had undergone reparative surgery and included venous pathway obstruction, pulmonary regurgitation and pulmonary hypertension. Additional factors which could have precipitated AFL in prone patients were present in 63. New symptoms appeared in 96 patients with the first attack of AFL. Ability Index prior to onset in 90 patients who have been followed-up for more than 1 year since the first onset was 1 in 52, 2 in 31, 3 in 6 and 4 in 1 patients. At the last visit (mean time from the first onset 6.6+/-4.7 years), only 9 patients remained with Ability Index 1, 43 in 2, 20 in 3 and 18 in 4 despite return to sinus rhythm.

CONCLUSION

One ventricle heart, ASD, transposition of great arteries and Tetrology of Fallot are the most common underlying anomalies in GUCH patients who develop AFL. It is less commonly seen in unoperated patients. When occurs AFL compromises patients' activities and deteriorates the clinical condition. Residual or developed haemodynamic abnormalities and precipitating factor are often present in this patients, hence full investigation and close follow up are necessary once AFL develops.

Use of a 3-dimensional electroanatomical mapping system for catheter ablation of macroreentrant right atrial tachycardia following atriotomy

The purpose of this study was to utilize a 3-dimensional (3D) electroanatomical mapping system (CARTO) to characterize the reentrant circuit in macroreentrant right atrial tachycardia (AT) following right atriotomy. Right atrial mapping was performed during incessant AT in a patient who had a right atriotomy for closure of an atrial septal defect. During AT, the right atrial free wall exhibited a large contiguous area of low bipolar voltage (< or =0.5 mV, 7.3 cm in length, and 6.3 cm in width). Two discrete scars, showing no electrical potential, were identified within the large low-voltage area. A larger vertical scar (thought to be from the atriotomy) and a smaller second scar (possible inferior vena cava cannulation scar) formed a narrow channel (1.5 cm in width) between these 2 scars. Right atrial activation propagated around the large upper scar, and then propagated through the channel between the 2 scars. A single application of radiofrequency current within the channel eliminated the macroreentrant AT. In conclusion, macroreentrant AT following right atriotomy was associated with 2 discrete scars and utilized the isolated channel between the 2 scars. Ablation within the channel effectively eliminated macroreentrant AT after atriotomy and eliminated the requirement for linear ablation between one or more of the scars and the tricuspid annulus.

Arrhythmias in Congenital Heart Disease

Improvements in surgical and medical treatment have led to improved survival of infants with congenital heart disease. Coincident with this improved survival has been an increase in the number of patients with congenital heart disease and arrhythmia. Arrhythmias in this population can be life threatening but are more commonly life altering, creating considerable patient distress--both from the symptoms of the arrhythmia and from fear of paroxysmal events. Arrhythmia in the setting of congenital heart disease can result from hemodynamic compromise and can in turn result in more hemodynamic compromise, creating a cycle of clinical deterioration. Aggressive treatment of arrhythmia and aggressive evaluation for surgically correctable hemodynamic burdens is therefore warranted. Treatment options for arrhythmia in patients with congenital heart disease include pharmacologic therapy, catheter intervention, implantable device therapy, and surgical intervention. Pharmacologic therapy is currently the primary mode of treatment of arrhythmia in this setting; however, data from large trials of patients with ischemic or dilated cardiomyopathy suggest that many antiarrhythmic agents may increase overall mortality rates in certain patient groups. In addition, pharmacologic therapy is associated with significant short- and long-term side effects, relatively low success rates, and problems with compliance. For these reasons and because of recent advances in catheter and device therapy, nonpharmacologic therapy should be considered in lieu of medication, whenever possible.

Preventing sudden death after repair of tetralogy of Fallot: complex therapy for complex patients

Sudden arrhythmic death in patients with repaired tetralogy of Fallot or its variants has a variety of causes. Consequently, it can serve as a paradigm for management of potentially malignant arrhythmias in all pediatric patients, particularly with regard to the use of nonpharmacologic therapy for management. Five cases are presented as touchpoints for discussion and demonstrate a number of important issues concerning the assessment and reduction of sudden cardiac death risk in these patients. First, there are no clinical parameters that can be used to accurately assess risk. Second, pharmacologic agents alone rarely are adequate therapy. Third, catheter ablation and antitachycardia devices continue to play an ever increasing role in management of these patients, and, finally, additional data are necessary to establish clear management guidelines in patients with congenital heart disease at risk for arrhythmic death.

Twenty-to-thirty-seven-year follow-up after repair for Tetralogy of Fallot

OBJECTIVE

To describe the long-term prognosis after repair of Tetralogy of Fallot with pulmonary stenosis beyond 20 years.

METHODS

One hundred and eighty five patients underwent corrective repair of Tetralogy of Fallot at Rigshospitalet in Copenhagen between January 1960 and July 1977. Ninety seven patients had undergone a palliative operation prior to Tetralogy of Fallot repair. All the 125 patients who were discharged from the hospital were traced through the population register and the patients alive July 1997 were contacted by mail and/or telephone and questioned about use of medicine, professional status, family status and ability to perform sport activities.

RESULTS

Sixty patients died in hospital and 125 patients, 78 males and 47 females, were discharged alive. Among operative survivors, median age at operation was 12.8 years (range 0.4-41 years). Thirteen patients required a reoperation, the main indication was failed VSD closure. There were 16 late cardiac deaths, out of which seven were sudden and unexpected and three were in immediate relation to reoperations. One hundred and nine patients were alive at follow-up. The mean follow-up time was 25.5 years (range 20-38 years). Sixteen percent used cardiac drugs, 89% were, or had been, working normally (all professions from academics to hard manual labors were represented), 53% (64% of women) had given birth after the repair and 51% performed sport activities regularly. No patients were lost to follow-up.

CONCLUSIONS

The vast majority of the patients seemed to live normal lives 20-37 years after Tetralogy of Fallot repair. Late deaths were cardiac in origin, including sudden death from arrhythmias. The number of late reoperation has been low. Considering the natural history of the disease, Fallot repair has proven to be a beneficial procedure even including the very early experience short after introduction of open heart surgery.

Value of programmed ventricular stimulation in patients with congenital heart disease

INTRODUCTION

The role of programmed ventricular stimulation (VSTIM) for risk stratification in congenital heart disease is unclear. We analyzed the results of VSTIM in selected congenital heart disease survivors at a single center to determine whether it improved the ability to predict a serious outcome.

METHODS AND RESULTS

Between July 1985 and September 1996, 140 primary VSTIM studies were performed on 130 patients (median age 18.1 years, range 0 to 51). Tetralogy of Fallot (33 %), d-transposition of the great arteries (25 %), and left ventricular outflow tract obstruction (12%) accounted for the majority of patients. Indications included spontaneous ventricular tachycardia (VT) of > or = 3 beats (72%) and/or symptoms (68%). Sustained VT was induced in 25% of the studies, and nonsustained VT in 12%. Atrial flutter or other supraventricular tachycardia was documented in 32% and bradyarrhythmias in 26%. By univariate analysis, mortality was increased in patients with positive VSTIM versus negative VSTIM (18% vs 7%, P = 0.04). Using multivariate analysis, positive VSTIM was associated with a sixfold increased risk of decreased survival and a threefold increased risk of serious arrhythmic events, allowing up to 87% sensitivity in predicting mortality. However, 7 (33%) of 21 patients with documented clinical VT had false-negative studies.

CONCLUSION

VSTIM in a large, selected group of congenital heart disease patients identified a subgroup with significantly increased mortality and sudden arrhythmic events. Failure to induce VT was a favorable prognostic sign, but the frequency of false-negative studies was high. Frequent supraventricular tachycardia further complicated risk stratification. Although VSTIM appears to be a reasonable tool for evaluation of this population, a larger, multicenter trial is recommended to clarify its utility.

[Arrhythmias in patients with congenital heart disease and their impact on prognosis]

Patients with congenital heart disease have an increased chance to suffer from brady- as well as tachyarrhythmias. The impact of these on quality of life, morbidity and mortality is more often imperative as compared to heart-healthy individuals. The substrate for these may be either congenital or acquired. Improvements of the surgical management of these patients have led, on the one hand, to improved survival rates with prolonged life expectancy within the last 2 decades, which on the other hand provided the basis for a higher rate of acquired cardiac arrhythmias. Together, this not only challenges diagnostics and therapy but also the prognostic relevance of these arrhythmias. The therapeutic strategies and prognostic markers have until now mostly been based on retrospective studies limited by the low number of patients and inhomogeneous patient selection. Despite these limitations, an increased risk of sudden cardiac death has been substantiated for certain patient groups, e.g., those operated on by the Mustard- or Senning procedures in patients with transposition of the great arteries and patients operated on with correction of the tetralogy of Fallot. However, until now it has not been possible to identify reliable markers for establishing the risk on an individual basis within these patient cohorts. For achieving reliable data on the symptomatic and prognostic effects of present-day--as well as new-coming--therapeutic strategies, it is mandatory to perform prospectively based, randomized multicenter studies. Furthermore, the well-appreciated synergism of hemodynamically and primarily of arrhythmia-based effects on prognosis could potentially be divided into their relative weight to better guide appropriate, substrate-related therapy. In addition, this should help to get better estimates of the risk for sudden cardiac death in different, etiologically homogeneous, groups of patients with congenital heart disease.

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 intraatrial reentrant tachycardia after surgery for congenital heart disease

Intraatrial reentry tachycardia is a common cause of both morbidity and mortality after surgery for a variety of congenital heart defects. Despite an armamentarium of arrhythmia management tools, including drug therapy, antibradycardia, and antitachycardia pacing, and catheter ablation, management of these arrhythmias remains a challenge. This report briefly reviews the problem, assesses the current successes and failures of radiofrequency catheter ablation for treating it, and discusses a number of ongoing developments that may improve both early and late outcome.

Sotalol for atrial tachycardias after surgery for congenital heart disease

Atrial tachycardias, in particular atrial flutter after surgery for congenital heart disease, is associated with a high mortality. Treatment with various antiarrhythmic drugs and/or antitachycardia pacemakers is not very successful. Sotalol, a Class III drug, has shown to be a promising drug in adults with atrial tachycardias. However, the experience with sotalol in children after surgery for congenital heart disease is limited. Therefore, we describe our results here. Between December 1990 and February 1997, 26 children with atrial tachycardias, most of them with atrial flutter or fibrillation (n = 20), after surgery for congenital heart disease were treated with sotalol orally. The age of the children at the start of treatment was 7.5 +/- 5.8 years (mean +/- SD). The time interval between surgery and the start of atrial tachycardia ranged from 1 day to 14.3 years (3.8 +/- 3.8 years). Conversion to sinus rhythm was achieved in 16 out of 22 hemodynamically stable children with a dosage of 4.0 +/- 1.6 mg/kg per day. The six children without sinus rhythm on sotalol and four hemodynamically unstable patients were treated prophylactically with sotalol after DC cardioversion for their tachycardias. Two children complained of mild transient fatigue. Heart rate decreased during therapy (95 +/- 33 vs 81 +/- 21 beats/min; P = 0.01). QTc-intervals did not change. Proarrhythmias such as torsades de pointes were not encountered. Two children with a preexistent sick sinus syndrome showed aggravation of bradycardia and needed pacemaker implantation. The percentage of children with a recurrence-free interval of 1 and 2 years was 96% and 81%, respectively, for all atrial tachycardias, and 92% and 66% for atrial flutter. The recurrences of atrial tachycardias during the follow-up period, which ranged from 0.1-6.1 years (2.5 +/- 1.8 years) could be treated with only an increase of the dosage of sotalol in all but one patient. We conclude that sotalol is an effective drug for the treatment and prevention of atrial tachycardia in children after surgery for congenital heart disease.

Intra-atrial reentrant tachycardia after palliation of congenital heart disease: characterization of multiple macroreentrant circuits using fluoroscopically based three-dimensional endocardial mapping

INTRODUCTION

The anatomic substrate of intra-atrial reentrant tachycardia (IART) following congenital heart surgery is poorly understood, but is presumed to be different than common atrial flutter.

METHODS AND RESULTS

To study the mechanisms of IART, we used a new technique for high-density endocardial mapping using recordings from a multipolar basket recording catheter (25 bipolar pairs). For each recording, biplane fluorographic reference points were digitized to obtain the spatial locations of electrode pairs, and activation times were calculated using temporal reference points from the surface ECG. Using custom software, data were combined to create three-dimensional atrial activation sequence maps, which were displayed as animated sequences. Using this technique, recordings were made in induced and/or spontaneous IART in 8 patients following congenital heart surgery (5 Fontan, 2 tetralogy of Fallot repair, 1 ventricular septal defect repair), and in 3 patients with normal intracardiac anatomy (1 with type I atrial flutter). Ten discrete IART activation sequences were recorded; 2 patients had 2 sequences each. IART maps were constructed using a median of 108 electrode positions (range 27 to 197) from a median of 6 recordings/sequence (range 3 to 11). Sinus or paced atrial rhythms were also recorded, and maps were created in a similar fashion. Visual analysis of activation sequences of sinus and paced rhythm were anatomically concordant with known mechanisms of atrial activation. IART sequences revealed diverse mechanisms; only 1 IART circuit was similar to that associated with common atrial flutter. Activation wavefront emergence from presumed zones of slow conduction, lines of conduction block, and apparent bystander activation were observed.

CONCLUSIONS

High-density atrial activation sequence maps demonstrate that IART following congenital heart surgery utilizes diverse circuits and is distinct from common atrial flutter. The technique used to create these three-dimensional activation sequences may improve understanding of these complex atrial arrhythmias and assist in the development of ablative therapies.

Mechanisms and therapy of complex arrhythmias in pediatric patients

In recent years, the distinction between the diagnostic and therapeutic techniques used in the assessment and management of pediatric and adult patients with arrhythmias has gradually blurred. Nonetheless, arrhythmias in the pediatric patient are still often different from the adult patient in one of two important ways. First, a variety of arrhythmia mechanisms remain relatively unique to the pediatric population, some because of developmental issues and others because of early presentation of an incessant tachycardia. Second, the presentation and management of certain arrhythmias is sometimes markedly affected by patient age or the presence of structural congenital heart disease. A sampling from each of the above categories is reviewed and discussed.