Ablation of 'incisional' reentrant atrial tachycardia complicating surgery for congenital heart disease. Use of entrainment to define a critical isthmus of conduction

Management of atrial fibrillation in patients with congenital heart defects

Due to improved surgical technologies and post-operative care, long-term survival has improved in patients with congenital heart disease. Atrial fibrillation (AF) is increasingly observed in this aging population and is associated with morbidity and mortality; however, reports about the pathophysiology and the outcome of different treatment modalities of AF are still scarce in patients with congenital heart disease. In this review, the authors describe the epidemiology, pathophysiology and outcome of the different therapies of AF in this specific patient population.

Arrhythmias in Complex Congenital Heart Disease

Late after surgical repair of complex congenital heart disease, atrial arrhythmias are a major cause of morbidity, and ventricular arrhythmias and sudden cardiac death are a major cause of mortality. The six cases in this article highlight common challenges in the management of arrhythmias in the adult congenital heart disease population.

[Interventional treatment of tachyarrhythmia in children with congenital heart disease]

In children and adolescents with congenital heart disease (CHD) tachyarrhythmia occurs more frequently compared to patients with otherwise normal hearts. Arrhythmia substrates may be a natural part of certain congenital cardiac malformations or may result from long lasting myocardial deterioration as a result of CHD and/or cardiac surgery. Treatment of tachycardia is more frequently required even in early childhood, as the impact on quality of life, morbidity and mortality is higher due to an often reduced hemodynamic tolerance. Over the past 20 years interventional electrophysiology has been established as the therapy of choice for the majority of chronic or chronically recurrent tachycardia even in children with CHD. The success and risks of treatment are predominantly influenced by the individual expression of the cardiac anomaly and, if surgery has been performed, the highly variant postoperative anatomy. Introduction of 3D electroanatomical mapping systems together with modern cardiac imaging tools have significantly contributed to an improved understanding, particularly in postoperative tachycardia. Despite such progress, success rates are lower and recurrences are more frequent compared to patients without CHD. Complex and often multiple tachycardia courses account for the still limited performance as well as a frequently insufficient lesion formation with the use of radiofrequency current in the hypertrophic and fibrotic myocardium. Electrophysiology in children and adolescents, particularly if CHD is present, represents a highly specialized discipline requiring a high expertise in CHD, CHD surgery and cardiac electrophysiology and is ideally imbedded within an interdisciplinary cardiological and cardiosurgical setting.

Simplified progressive approach for the ablation of scar related atrial macroreentrant tachycardias

INTRODUCTION

Radiofrequency ablation of scar related right atrial flutter is challenging. Long procedures, prolonged fluoroscopic times and high percentages of recurrences are of concern. We present a simple and progressive approach based on a single electroanatomic map of the right atrium.

METHODS

Twenty-two consecutive patients with atrial flutter and history of cardiac surgery were included. An electrophysiologic study was performed to define localization (left or right) and cavo-tricuspid isthmus participation using entrainment mapping. After a critical isthmus was localized, ablation was performed with an external irrigated tip catheter with a power limit of 30 W. Potential ablation sites were confirmed by entrainment.

RESULTS

The predominant cardiopathy was atrial septal defect. All arrhythmias were localized in the right atrium; mean cycle length of the clinical flutter was 274 ± 31 ms. Only 40% had cavo-tricuspid isthmus participation. None of the patients with successful ablation had recurrences after 13 ± 9.4 months of follow-up.

CONCLUSIONS

A progressive approach with only one activation/voltage CARTO(®) map of the atrium and ablation of all potential circuits is a highly effective method for ablating scar related macroreentrant atrial arrhythmias.

Catheter ablation of atrial arrhythmias: state of the art

Catheter ablation is at the forefront of the management of a range of atrial arrhythmias. In this Series paper, we discuss the underlying mechanisms and the current role of catheter ablation for the three most common atrial arrhythmias encountered in clinical practice: focal atrial tachycardia, atrial flutter, and atrial fibrillation. The mechanisms of focal atrial tachycardia and atrial flutter are well understood, and these arrhythmias are amenable to curative catheter ablation with high success rates. In most cases, paroxysmal atrial fibrillation is initiated by triggers located within pulmonary vein musculature. Circumferential ablation to isolate this musculature is associated with high success rates for elimination of paroxysmal atrial fibrillation in selected populations. Because of the problem of recurrent pulmonary vein connection, more than one procedure will be needed in about 30% of patients, and new technologies are being developed to reduce this occurrence. The mechanisms that sustain persistent atrial fibrillation are not well understood and are the subject of continuing investigation. As such, ablation approaches and technologies for this arrhythmia are still evolving.

Importance of tachycardia cycle length for differentiating typical atrial flutter from scar-related in adult congenital heart disease

BACKGROUND

 Radiofrequency catheter ablation (RFCA) for intraatrial reentrant tachycardia (IART) in congenital heart disease (CHD) remains difficult.

METHODS

 Thirty-four consecutive adult patients (age, 37.6 ± 12.8 years; male, 21) with previously repaired CHD and IART underwent an electrophysiological study and RFCA. CHD included atrial septal defect (ASD, n = 14), tetralogy of Fallot (n = 11), ventricular septal defect (n = 4), pulmonary atresia (n = 2), atrioventricular septal defect (n = 1), transposition of the great arteries (n = 1), and double-outlet right ventricle (n = 1).

RESULTS

 Duration of CHD repair to IART onset was 19.1 ± 8.5 years. Thirty and four patients had single- and double-loop reentrant tachycardia, respectively. Among the total of 38 IARTs, which were mapped, 22 (57.9%) and 13 (34.2%) IARTs were cavotricuspid isthmus (CTI)-dependent atrial flutter (AFL) and scar-related AFL, respectively. Typical AFL electrocardiography findings including definite sawtooth appearance in inferior leads and positive F wave in lead V1 were observed in only 12 of 21 patients (57.1%) with CTI-dependent AFL. CTI-dependent AFL had a significantly longer tachycardia cycle length (TCL) than scar-related AFL (267.6 ± 34.4 ms and 235.9 ± 37.0 ms, respectively; P = 0.031). TCL > 250 ms had 79% sensitivity as the cutoff value for differentiating CTI-dependent from scar-related AFL. The acute success rates of RFCA in CTI-dependent and scar-related AFLs were 85.7% and 90.0%, respectively. The recurrence rates in CTI-dependent and scar-related AFLs were 11.1% and 11.1%, respectively, during a follow-up of 21.2 ± 28.3 months.

CONCLUSIONS

 CTI-dependent AFL was the most common IART in adult patients with repaired CHD and was easily manageable by RFCA. TCL might help to differentiate CTI-dependent AFL from other IARTs.

Safety and feasibility of intra-operative device closure of atrial septal defect with transthoracic minimal invasion

OBJECTIVE

The study aims to evaluate the safety and feasibility of intra-operative device closure of atrial septal defect with transthoracic minimal invasion.

METHODS

From May 2006 to June 2009, 252 patients with secundum-type atrial septal defect closure were enrolled in our institution. The patients were divided into two groups, with 182 patients in group I with intra-operative device closure and 72 in group II with surgical closure. In group I, the patients' age ranged from 3 months to 62 years (mean±standard deviation, 19.0±16.7 years). This approach involved a transthoracic minimal invasion that was performed after full evaluation of the atrial septal defect by transthoracic echocardiography, deploying the device through the delivery sheath to occlude the atrial septal defect.

RESULTS

In group I, 180 patients were occluded successfully under this approach. The size of the occluder device implanted ranged from 6 to 48 mm. Minor complications occurred, which included transient arrhythmias (n=23) and pleural effusion (n=15). Two patients with postoperative cardiac arrest were successfully cardiopulmonary resuscitated. Another two patients with occluder dislodged back into the right atrium were turned to surgical repair with cardiopulmonary bypass on the postoperative day. In group II, all patients were occluded successfully, and almost all patients needed blood transfusion and suffered from various minor complications. All discharged patients were followed up for 1-5 years. During this period, we found no recurrence, no thrombosis, even no device failure. In our comparative studies, group II had significantly longer intensive care unit (ICU) stay and hospital stay than group I (p<0.05). The cost for group I was less than group II (p<0.05).

CONCLUSIONS

Intra-operative device closure of atrial septal defect with transthoracic minimal invasion is a safe and feasible technique. It had the advantages of cost savings, yielding better cosmetic results, and leaving less trauma than surgical closure.

Supraventricular arrhythmias late after orthotopic cardiac transplantation: electrocardiographic and electrophysiological characterization and radiofrequency ablation

AIMS

Cardiac transplantation (CTX) is an effective treatment for end-stage heart disease. Cardiac arrhythmias are increasingly recognized and associated with significant morbidity and mortality. We aim to describe the clinical and electrophysiological characteristics of patients with atrial arrhythmias occurring late after CTX.

METHODS AND RESULTS

Sixteen patients with prior CTX who presented with late atrial arrhythmias for electrophysiological studies (EPS) were identified at two cardiac transplant centres. Among 859 patients, 16 (mean age 52 ± 14 years, 11 of 16 were men) patients underwent EPS for atrial arrhythmias presenting 8.6 ± 5.7 years following CTX. Among 16 patients, 14 underwent cardiac alone and 2 included lung transplantation. There were no cases of cardiac rejection. Arrhythmias were due to counterclockwise cavotricuspid-dependent atrial flutter (AFL) in 10 of 16, atrial tachycardia (AT) in 6 (1 patient had AFL and AT), and 1 due to atrioventricular nodal re-entrant tachycardia. Recipient-donor atrial electrical connection was seen in two of six AT and in no cases of AFL. In two cases, a focal AT was mapped to the remnant atrium conducting 2 : 1 or at variable block to the donor atrium. In four cases a focal/micro re-entrant AT originated within the vicinity of the interatrial suture scar. All cases were successfully ablated with radiofrequency energy; however, one case of AFL required a repeat ablation. Patients remained free of arrhythmia at 34 ± 15 months post-ablation.

CONCLUSION

Typical AFL and AT are the most frequent supraventricular arrhythmias occurring late following CTX. Focal ATs may originate in low-voltage or border zones immediately adjacent to the atrio-atrial anastomosis. Radiofrequency ablation is an effective treatment strategy with high long-term success.

Intraoperative device closure of atrial septal defects in the older population

Objective

This study sought to prove the safety and feasibility of intraoperative device closure of atrial septal defect (ASD) with transthoracic minimal invasion in the older patients.

Methods

From January 2006 to December 2009, 47 patients aged 50 years or more and suffered from atrial septal defect were enrolled in our institution. Patients were divided into two groups, 27 of which in group I with intraoperative device closure and the other 20 in group II with surgical closure. In group I, the method involved a minimal intercostal incision, which was performed after full evaluation of the atrial septal defect by transthoracic echocardiography, and the insertion of the device through the delivery sheath to occlude the atrial septal defect.

Results

In group I, implantation was ultimately successful in all patients. The complete closure rate at 24 hours and 1 year were 81.5% and 100% respectively. In 6 of 27 patients, minor complications occurred: transient arrhythmia (n = 5) and blood transfusion (n = 3). In group II, all patients were closured successfully; almost all of them needed blood transfusion and suffered from various minor complications though. During a follow-up period of 1 to 5 years, no residual shunt, noticeable mitral regurgitation, significant arrhythmias, thrombosis, or device failure were found. In our comparative studies, group II had significantly longer ICU stay and hospital stay than group I (p < 0.05). The cost of group I was less than that of group II(p < 0.05).

Conclusions

Minimally invasive transthoracic device closure of the atrial septal defect at advanced age with a domestically made device without cardiopulmonary bypass is safe and feasible under transthoracic echocardiographic guidance. It was cost-savings, yielding better cosmetic results and leaving fewer traumas than surgical closure. Early and mid-term results are encouraging. However, it is necessary to evaluate the long-term results.

Congenital heart defects in adulthood

BACKGROUND

More than 90% of children with congenital heart defects now survive into adulthood; just a few decades ago, survival was rare, particularly among patients with complex defects. The new population of adults with congenital heart disease presents a special challenge to physicians from all of the involved specialties.

METHODS

Selective literature review.

RESULTS AND CONCLUSION

A complete cure of the congenital heart defect in childhood is exceptional, and most adult patients continue to suffer from residual problems and sequelae. Further surgery or catheter interventions may be needed. Potential late complications include arrhythmias, heart failure, pulmonary hypertension, endocarditis, and thromboembolic events. The management of these patients during pregnancy or non-cardiac surgery remains a challenge. If this evolving patient population is to receive the best possible care, the adequate provision of specialized medical services is a necessary, but not sufficient, condition: patients and their referring physicians will also need to be aware that these services are available, and then actually make use of them. Moreover, optimal communication among all of the involved physicians is essential.

Catheter ablation of non-inducible atrial tachycardia after surgical repair of heart disease

We present a patient with non-inducible atrial tachycardia (AT) after atriotomy for surgical repair of heart disease who underwent ablation successfully. Using a 3-D mapping system, we presumed the atriotomy site on the lateral right atrial wall by searching for linear double potentials (DP) during sinus/paced rhythm from the coronary sinus, but it was evaluated incompletely. We could verify the edges of the atriotomy scar precisely by pacing from close to the linear DP lesion and the opposite site. After ablation between the presumed atriotomy scar and the inferior vena cava and cavotricuspid isthmus, no AT recurred without anti-arrhythmic drugs.

Long-term outcome following ablation of atrial flutter occurring late after atrial septal defect repair

AIMS

In patients with surgical atrial septal defect (ASD) repair, late atrial flutters (AFLs), including cavotricuspid isthmus (CTI)-dependent and non-CTI-dependent scar-related flutter (AFL), are common. Radiofrequency ablation (RFA) of these arrhythmias has a high acute success rate. We aimed to characterize the long-term freedom from atrial arrhythmias in this population.

METHODS

Twenty consecutive patients undergoing RFA for AFL late after ASD repair were included. Electrophysiological assessment included multipolar activation, entrainment, and electroanatomic mapping. Clinical, electrocardiograph, and Holter monitoring follow-up was conducted every 6 months.

RESULTS

Mean age was 53 ± 13 years. Time from surgical repair to RFA was 29 ± 15 years. All patients had CTI-dependent AFL (20/20). There were 1.6 ± 0.7 arrhythmias per patient; other arrhythmias included non-CTI-dependent AFL (14), focal atrial tachycardia (two), and atrioventricular nodal reentry tachycardia (two) . Acute success was obtained in 100%. Five patients with recurrent AFL (three CTI dependent, two non-CTI dependent) at 13 ± 8 months had successful repeat RFA. At 3.2 ± 1.6 years follow-up since the last procedure, 90% of patients with successful RFA for AFL remained free of their clinical arrhythmia. However, 30% of the original 20 patients had documented atrial fibrillation (AF) 2.1 ± 1.6 years after the last procedure; five (25%) required AF intervention. One stroke (5%) occurred in the context of late AF.

CONCLUSION

RFA of AFL occurring late after surgical ASD repair has a low long-term risk of recurrence, although 25% of patients required two procedures. However, there is a high late incidence of AF (30%), with an additional 25% of patients requiring intervention for AF.

Arrhythmogenic causes of chest pain in children

Although cardiac causes of chest pain in children are infrequent, arrhythmias are implicated in most cardiac related cases. The most common arrhythmias associated with chest pain are supraventricular tachycardias, but more ominous rhythms, such as ventricular tachycardia or bradycardias, can manifest as chest pain. Investigation of all children with chest pain suspected of arrhythmia should include detailed history and physical examination and a 12- or 15-lead electrocardiogram. In some cases echocardiogram, 24-hour Holter monitoring, exercise stress testing, or other cardiac evaluations may be indicated. Children with a history of cardiac disease or cardiac surgery are particularly at risk for arrhythmias and may experience chest pain in association with their arrhythmias.

Outcome of intra-atrial re-entrant tachycardia catheter ablation in adults with congenital heart disease: negative impact of age and complex atrial surgery

OBJECTIVES

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.

BACKGROUND

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.

METHODS

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.

RESULTS

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.

CONCLUSIONS

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.

Higher rate of recurrent atrial flutter and atrial fibrillation following atrial flutter ablation after cardiac surgery

INTRODUCTION

Atrial flutter (AFL) is common after cardiac surgery. However, the types of post-cardiac surgery AFL, its response to catheter-based radiofrequency ablation, and its relationship to atrial fibrillation (AF) are unknown.

METHODS AND RESULTS

We retrospectively studied all patients who underwent mapping and ablation for AFL after cardiac surgery from January 1990 to July 2004. One hundred randomly selected patients without prior cardiac surgery (PCS) who underwent mapping and ablation of AFL served as the control population. A total of 236 patients formed the study population (mean age 62 + 13 years, 22% female) and 100 patients formed the control population (mean age 60 + 13 years, 25% female). The majority of patients without PCS had cavo-tricuspid isthmus (CTI)-dependent AFL when compared to patients with PCS (93% vs 72%, respectively, P < 0.0001). In contrast, scar-related AFL was more common in patients with PCS as compared to patients without PCS (22% vs 3%, P < 0.0001). Predictors of scar related AFL in multivariable regression analysis included PCS and left-sided AFL. Acute success rates and complications were similar between the groups. When compared to patients with AFL ablation without PCS, those that had AFL after PCS had higher rates of recurrence of both AFL (1% vs 12%, P < 0.0001; mean time to recurrence 1.85 years) and AF (16% vs 28%, P = 0.02; mean time to recurrence 2.67 years).

CONCLUSION

Despite ablation of AFL, patients with PCS have a higher rate of AFL and AF when compared to patients without PCS who underwent ablation of atrial flutter during long-term follow-up.

Linear ablation of right atrial free wall flutter: demonstration of bidirectional conduction block as an endpoint associated with long-term success

INTRODUCTION

Ablation for atypical atrial flutter (AFL) is often performed during tachycardia, with termination or noninducibility of AFL as the endpoint. Termination alone is, however, an inadequate endpoint for typical AFL ablation, where incomplete isthmus block leads to high recurrence rates. We assessed conduction block across a low lateral right atrial (RA) ablation line (LRA) from free wall scar to the inferior vena cava (IVC) or tricuspid annulus in 11 consecutive patients with atypical RA free wall flutter.

METHOD AND RESULTS

LRA block was assessed following termination of AFL, by pacing from the ablation catheter in the low lateral RA posterior to the ablation line and recording the sequence and timing of activation anterior to the line with a duodecapole catheter, and vice versa for bidirectional block. LRA block resulted in a high to low activation pattern on the halo and a mean conduction time of 201 +/- 48 ms to distal halo. LRA conduction block was present in only 2 out of 6 patients after termination of AFL by ablation. Ablation was performed during sinus rhythm (SR) in 9 patients to achieve LRA conduction block. No recurrence of AFL was observed at long-term follow-up (22 +/- 12 months); 3 patients developed AF.

CONCLUSION

Termination of right free wall flutter is often associated with persistent LRA conduction and additional radiofrequency ablation (RFA) in SR is usually required. Low RA pacing may be used to assess LRA conduction block and offers a robust endpoint for atypical RA free wall flutter ablation, which results in a high long-term cure rate.

Congenitally closed tricuspid annulus functions as arrhythmogenic substrate of atrial arrhythmia in patient with tricuspid atresia

An intraatrial reentrant circuit was identified using an electroanatomical mapping system and evaluation of postpacing intervals in a patient with tricuspid annulus. Intraatrial reentrant tachycardia was successfully eliminated on the basis of the interpretation that the reentry circuit depends on a congenitally closed tricuspid annulus. We report that a congenitally closed tricuspid annulus is one of the anatomical obstacles when we consider atrial tachyarrhythmia.

Cluster of multiple atrial tachycardias limited to pregnancy after radiofrequency ablation following senning operation

This case report describes a female patient with a cluster of four supraventricular tachycardias during the third trimester of pregnancy. The patient was surgically corrected with a Senning operation at the age of 15. Due to numerous monomorphic atrial tachycardias at the age of 28 an ablation using the noncontact mapping system EnSite 3000 was successfully performed. She remained free of tachycardias for 2 years until the third trimester of pregnancy, where 4 electrical cardioversions and eventually a caesarean section were performed. Subsequently, the patient was free of tachycardias during a 36 month follow-up and the child is healthy.

Arrhythmia management in the Fontan patient

With longer duration of follow-up, as many as 50% of Fontan patients will develop atrial tachycardia, usually in association with significant hemodynamic abnormalities. Arrhythmia management in the Fontan patient is reviewed. The incidence and type of arrhythmia occurrence are examined, including macro-reentrant rhythm which involves the right atrium, reentrant rhythm localized to the pulmonary venous atrium (seen in patients with lateral tunnel procedures), and atrial fibrillation. Risk factors for development of these arrhythmias are considered, and short- and long-term therapeutic options for medical and surgical treatment are discussed. Surgical results are presented for 117 patients undergoing Fontan conversion and arrhythmia surgery (isthmus ablation (9), modified right atrial maze (38) or Cox-maze III (70)). Operative mortality is low (1/117, 0.8%). Seven late deaths occurred, and include two patients who died shortly following cardiac transplantation (2/6, 33%) after Fontan conversion and arrhythmia surgery. Overall arrhythmia recurrence is 12.8% during a mean follow-up of 56 months. Fontan conversion with arrhythmia surgery can be performed with low operative mortality, low risk of recurrent tachycardia, and marked improvement in functional status in most patients. Because the development of tachycardia is usually an electromechanical problem, attention to only the arrhythmia with medications or ablation may allow progression of hemodynamic abnormalities to either a life-threatening outcome or a point at which transplantation is the only potential option. Because cardiac transplantation in Fontan patients is associated with high early mortality, earlier consideration for surgical intervention is warranted.