p.41 抽出テキスト

................................................................................................................................................................ studies do not confer absolute certainty about risk assessment. In a recent retrospective study in 912 young patients (aged <_21 years) with WPW syndrome, 96 experienced life-threatening events,405 of whom 49% had rapidly conducted pre-excited AF. In patients with events subjected to EPS risk stratification, 22 of 60 (37%) did not have EPS-determined high-risk characteristics, and 15 of 60 (25%) had neither concerning pathway characteristics nor inducible AVRT. There has also been evidence supporting the notion of LV dysfunction related to electrical asynchrony in patients, especially children, with asymptomatic pre-excitation.478481 It seems reasonable to recommend EPS and consider ablation if a link between pre-excitation and LV dysfunction can be made.

Catheter ablation of an asymptomatic ‘low-risk’ AP also appears reasonable in appropriately experienced centres according to informed patient choice. However, when a decision is made to perform catheter ablation, it is important to recognise that ablation of APs in the anteroseptal or mid-septal (MS) region is associated with a small risk of AV block. The risk of heart block associated with ablation of anteroseptal or MS APs may preclude ablation of an anteroseptal or MS AP in an asymptomatic patient. Thus, the approach for patients with asymptomatic pre-excitation that does not exhibit high-risk characteristics at EPS depends on the experience and expertise of the electrophysiologist performing the procedure, as well as the preferences and values of the patient. In the CASPED registry involving 182 children and adolescents with asymptomatic pre-excitation, catheter ablation achieved a 91% success rate without significant complications.482

12 Supraventricular tachycardia in

adults with congenital heart disease

The number of adults with congenital heart disease is increasing at a rate of 60% per decade in developed countries.483,484 Currently, it is estimated that 1 million adults with congenital heart disease live in the European Union. Despite ongoing advances in paediatric surgery and cardiology, allowing >90% of children born with congenital heart disease to survive to adulthood,485 these patients usually continue to be afflicted by late complications leading to increased morbidity and mortality. Alongside HF, cardiac arrhythmias are a common late complication in adults with congenital heart defects.486 This is due to the underlying cardiac defect, previous or persisting haemodynamic issues, and previous surgical interventions resulting in myocardial damage and scarring.487 Arrhythmic burden ranges from bradycardia arrhythmias to SVTs, and life-threatening VTs or fibrillation. Owing to preceding operations and underlying anatomy, patients with tetralogy of Fallot, Ebstein’s anomaly, transposition of the great arteries after atrial switch procedure, and complex patients with univentricular hearts and Fontan palliation are especially prone to late development of arrhythmias, such as incisional or intra-atrial re-entry tachycardia, and ventricular tachycardia.488 However, even patients with usually non-complex lesions such as atrial septal defects have an increased life risk of atrial arrhythmias.

In addition to being related to symptoms, SVTs have been reported as risk factors for sudden cardiac death in patients with ACHD. This issue particularly affects patients with obstructive lesions of the systemic ventricle, tetralogy of Fallot, after Fontan operation, and a systemic right ventricle.489,490 Unfortunately, diagnosis and treatment of arrhythmias in ACHD patients is complicated by the unusual nature of tachycardia, complex intracardiac anatomy, and especially by difficulties in accessing the heart, for example due to abnormal venous anatomy (e.g. azygos continuity or previous Fontan operation). As a consequence, specific expertise in patients with ACHD and access to adequate electrophysiological tools are required when performing catheter ablation procedures in these patients.

12.1 Pharmacological antiarrhythmic

therapy Acute therapy of SVT in the context of ACHD is as described for narrow QRS SVT, in general.491,492 Randomized controlled trials of chronic antiarrhythmic therapy in patients with complex ACHD are lacking. All antiarrhythmic drugs carry a proarrhythmic risk, and many patients with ACHD have underlying sinus node dysfunction or a predisposition for AVN disease. Antiarrhythmic drugs should therefore be used with particular caution, and are generally reserved for symptomatic patients after options for catheter ablation procedures and haemodynamic optimization (e.g. correction of underlying valvular problems) have been exhausted. Beta-blockers may be used to slow AV nodal conduction and may be considered, with caution, in patients with transposition of the great arteries after the atrial switch operation. This is supported by studies reporting a reduction in ventricular fibrillation and/or appropriate ICD shocks in patients treated with beta-blocking drugs.493,494 However, care is needed as these patients may suffer from chronotropic incompetence and cannot tolerate beta-blockade.495 Owing to recognized pro-arrhythmic effects, class IC drugs should be used with appropriate caution in the ACHD setting. Similar considerations refer to quinidine, disopyramide, and sotalol. In the recent report of the DARE study cohort, amiodarone, flecainide, and sotalol were clearly found to be pro-arrhythmic, especially in the presence of a prolonged QT, in older women, and in patients with underlying cardiovascular comorbidity, family history of sudden death, and hypokalaemia.496 Flecainide is highly effective in infants with SVT, but there are concerns about its toxicity at older ages.496,497 Most centres have a lower threshold for the use of amiodarone in patients with ACHD as it is perceived to be less proarrhythmic. However, it is commonly associated with thyroid disorders and less commonly with other well-described potentially life-changing complications. These considerations should severely limit its long-term use in patients with ACHD, thus further supporting the first-line use of ablation attempts wherever possible.498 Downloaded from academic.oup.com/eurheartj/article/41/5/655/5556821 by guest on 07 October 2026