Материал: 2019 ESC - supraventricular tachycardia

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.478 481 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

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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

12.2 Catheter and surgical ablation

Owing to underlying anatomy and previous operations, interventional access for ablation procedures may be challenging in patients with ACHD. In addition, the nature of SVT is often atypical, and related to multiple re-entrant circuits and fibrotic atrial tissue. As a consequence, special expertise and experience with ablation of complex tachyarrhythmias and scar-related procedures are necessary.506 It is recommended that patients with complex incisional tachycardias are referred to specialist centres with adequate experience, volumes of ablation procedures, and advanced mapping capabilities. Catheter ablation procedures in the setting of ACHD are associated with lower success rates compared with the general cohort of patients with AF or atrial flutter.484 However, ablation of CTI-related arrhythmias has been reported to have a high acute success rate (>95%), although the mid-term recurrence rate may approach 20%.507 Pre-operative catheter ablation or concomitant arrhythmia surgery should be considered in patients with ACHD undergoing cardiac surgery, as its incorporation can result in improved functional class and potentially decreased requirements for chronic antiarrhythmic medication in this vulnerable population.502 504

12.3 Specific disease states

12.3.1 Atrial septal defect

The incidence of atrial arrhythmias in patients with atrial septal defects ranges between 5 15%.508 The exact impact of atrial septal defect closure, especially of late closure, on the risk of developing AT is controversial. Patients commonly present with RA MRAT. The leading

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mechanism is CTI-dependent tachycardia and this is generally susceptible to catheter ablation. However, CTI-dependent and ‘incisional’ atrial flutter may coexist. Closure of an existing atrial septal defect, in isolation, is generally insufficient to abolish an existing AT and catheter ablation should be considered before defect closure. Mid-term recurrence rates of 40 44% have been reported in atrial septal defect patients post-flutter or AF ablation508,509; however, this should not preclude ablation procedures wherever possible.

12.3.2 Ebstein’s anomaly

ATs are common in Ebstein’s anomaly, occurring in 25 65% of patients.501,510 512 The types of arrhythmia include atrial flutter, focal AT, and AF. In addition, 10 45% of patients have right-sided APs, including WPW syndrome. More than one AP is common in this setting, and can in itself increase the risk of haemodynamic compromise and sudden cardiac death. Catheter ablation of APs has a high success rate; however, ablation procedures may be challenging and repeat procedures may be necessary as some patients have multiple ablation targets. In addition, patients may develop different arrhythmia mechanisms following ablation.501 In patients undergoing surgical repair, routine pre-operative EPS can be recommended as the diagnostic and therapeutic yield in this population is high.513

12.3.3 Transposition of the great arteries (dextrotransposition of the great arteries) after atrial switch operation (Mustard or Senning)

Owing to previous surgery and scarring, atrial re-entrant tachycardias are common in patients with a Mustard or Senning repair. In addition,

sinus node dysfunction may occur as a consequence of the atrial redirection procedure.495 As tachycardia is not well tolerated in patients with asystemic right ventricular and diastolic dysfunction, maintaining long-term sinus rhythm is highly desirable in this setting. Use of antiarrhythmic drugs is limited due to ventricular and sinus node dysfunction, and pro-arrhythmic risk. Ablation procedures in patients with a Mustard or Senning repair have a high acute success rate; however, recurrence rates approach 30% during long-term follow-up.500,514 516

12.3.4 Tetralogy of Fallot

SVTs are not uncommon in patients with tetralogy of Fallot. In addition to being related to symptoms, the occurrence of supraventricular arrhythmias has been linked to a statistically higher risk of sudden cardiac death in this population.517 As catheter ablation has a high procedural success rate, it should be considered as a first-line option in this setting.518 In addition, patients with new-onset atrial arrhythmias should be thoroughly evaluated to exclude addressable haemodynamic lesions such as severe pulmonary valve regurgitation, which may be amenable to surgical or interventional therapy leading indirectly to reduced arrhythmia burden.

12.3.5 Fontan repairs

AT is common in patients post-Fontan palliation. Patients with a classic (atriopulmonary) Fontan procedure are at especially high risk for AT, with <60% developing SVTs after 15 years of follow-up.519 In addition to symptoms and the risk of cardiac thromboembolism, AT is poorly tolerated haemodynamically in patients with univentricular hearts, and may lead to acute deterioration and overt HF in this setting.520 Catheter ablation is often effective but challenging, due to the nature of the arrhythmia circuits as well as issues with cardiac access.514,515 Various surgical modifications, such as the conversion to total cavopulmonary connection, have evolved and can ameliorate the risk of atrial arrhythmias.521

13 Supraventricular tachycardia in the paediatric population

Specific detailed recommendations for paediatric patients are published elsewhere522,523 and are beyond the scope of this document. In general, certain aspects are different in the paediatric population and should be taken into account.

Immaturity of the cardiac structures, including conduction tissue, may lead to modifications in the electrophysiology of the heart. Therefore, some APs present in the first months of life (even those associated with tachycardias) may disappear before the first year of age.522 Actually, AVRT due to WPW that begins in infancy may resolve in 90% of patients, but may recur in later childhood in

30 - 50% of patients; however, if the tachycardia is present after the age of 5, it persists in >75% of patients.524

It is clear that small children may not complain of symptoms, so indirect signs have to be assessed when SVT is suspected, i.e. irritability, failure to thrive, and even flat growing curves. It is not uncommon to discover an incessant SVT in a patient presenting with cardiogenic

shock due to TCM. This most frequently occurs in relatively slow SVTs, such as PJRT and focal AT.525,526

Pharmacokinetics and pharmacodynamics in children are different to those in adults; therefore, special attention has to be given when prescribing drugs.527 This is particularly important in newborns as

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milk can substantially modify the absorption of the drug and, as feeding schedules tend to be erratic, can affect effective drug availability. Furthermore, many drugs have to be prepared at specialized pharmacies, adding to the risk of incorrect dosing, and drug solutions may also need to be stored under special conditions to maintain their stability. This can be inconvenient when long-term treatment is required as, for example, a portable cooler bag must be carried. In addition, the long-term effects of some drugs, as they accumulate, are especially dangerous in growing bodies. This is of special interest regarding amiodarone, which can chronically provoke the same secondary effects as it does in adults. Verapamil has to be avoided whenever possible or given very carefully to small patients as it can provoke severe hypotension.522 A decreased response of adenosine in younger children has also been suggested.528

Invasive techniques are possible and effective even in very small children, when indicated, but there are several limiting factors. First, radiofrequency lesion formation in immature sheep myocardium is similar to that in adult sheep myocardium acutely, but is associated with late lesion enlargement and fibrous tissue invasion of normal myocardium. These observations may have implications for clinical radiofrequency ablation procedures in infants529 and avoidance of radiofrequency ablation, if at all possible, in the first 2 years of life is prudent. Second, no specific catheters and tools exist for the paediatric population. Currently, available catheters (minimum 5 French for non-irrigated radiofrequency tips) and curves are, in general, too large. This is particularly limiting in small children needing an ablation to resolve incessant tachycardia. Finally, the experience of the operator and the centre is crucial. Small patients requiring ablation should be referred to experienced reference centres for treatment. The number of catheters used, and procedural and radiation times, should be minimized in these growing bodies.530 Electroanatomical mapping systems are most valuable in this setting.

13.1 Foetal arrhythmias

Foetal arrhythmias can be detected at an early gestational age, with incessant, rapid SVTs associated with foetal death due to hydrops. Therefore, a special effort has to be made to detect and control foetal arrhythmias. A strong correlation between post-natal SVT and later gestational age at foetal SVT diagnosis has been reported.531 Diagnosis relies on echocardiography as foetal ECGs are not available in most clinics (it is used in just a few centres worldwide and primarily for research purposes).532 When sustained foetal tachycardia is observed, treatment is mandated. There are several protocols for this purpose, and they are mostly based on digoxin, flecainide, and sotalol alone or in combination depending on the type of tachycardia. These drugs have to be given to the mother, with a fraction reaching the foetus. This means that the secondary effects of these drugs can manifest in both the foetus and mother. Close follow-up is therefore needed.522,533,534

14 Supraventricular tachycardia in pregnancy

Sustained SVT becomes more frequent during pregnancy, occurring in 22 24/100 000 pregnancies. It may even manifest for the first time, particularly in the third trimester or peri-partum, according to comprehensive discharge data from hospitals.535 The overall

frequency of any arrhythmia is greater in women aged 41 50 years (199/100 000) than in those aged 18 30 years (55/100 000), which may be due to more prevalent AF and VT, whereas SVT seems stable over time.535 Arrhythmias are also more frequent among women with congenital heart disease, particularly atrial flutter, compared with women without congenital defects.536

As substantive prospective or randomized studies are unavailable, recommendations are primarily based on small cohorts or case reports in conjunction with expert opinion.

14.1 Maternal, obstetric, and offspring risk

SVT is associated with an increased risk of death during pregnancy, and the reported frequency is 68 per 100 000 pregnancy-related hospitalizations for any arrhythmia, 22 per 100 000 for SVT, 4 per 100 000 for atrial flutter, 27 per 100 000 for AF, 2 per 100 000 for ventricular fibrillation, and 16 per 100 000 for VT.535

Identification and treatment of underlying conditions are the first priorities. Although most of the exacerbations of SVT during pregnancy are benign and can be treated effectively with standard medical therapy,537 the circumstances that should be considered include the well-being of the foetus and the effects on labour, delivery, and lactation. The haemodynamic effect of tachycardia, as well as side effects of treatments, must be balanced and addressed for the foetus. Catheter ablation should therefore be considered before pregnancy when possible in patients with a known history of symptomatic tachyarrhythmia. Trials evaluating the level of surveillance at delivery are needed.

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14.2 Therapy

14.2.1 Antiarrhythmic drugs

Treatment with antiarrhythmic drugs for the prevention of SVT should, in general, be reserved for SVTs causing haemodynamic compromise or significant symptoms. The major concern regarding the use of antiarrhythmic drugs during pregnancy is potential adverse effects on the foetus. While the first trimester is associated with the greatest teratogenic risk, drug exposure later in pregnancy may result in adverse effects on foetal growth and development, and on uterine contractility, and an increased risk of pro-arrhythmia. The risks and benefits of continuing vs. stopping medication must be carefully considered in terms of the risk of recurring SVT, and the potential for haemodynamic compromise. Decisions should be individualized, based on the clinical situation and possible additional structural heart disease. Major controlled studies of antiarrhythmic drugs during pregnancy are lacking. If non-invasive manoeuvres fail, adenosine should be the first-line drug for treatment if needed during the second and third trimesters. There is a paucity of data on management of SVT in the first trimester.542 All beta-blockers can cause bradycardia and hypoglycaemia in the foetus. As beta-1 selective beta-blockers are less likely to affect uterine relaxation, they are preferred.546 Maternal use of beta-blockers in the first trimester has not been associated with a large increase in the risk for overall or cardiac malformations.548,553 However, in the EUROmediCAT study, an association between alpha/beta-adrenergic blocker use in the first trimester with multicystic renal dysplasia was reported.554 There have been concerns about ‘low weight for gestational age’ with beta-blockers, although the effects reported may not be large enough to be of clinical importance. Exposure to atenolol has been associated with a

higher risk of infants born small for their gestational age compared with metoprolol and propranolol, consistent with this association not being a class effect.543,555 Diltiazem has been found to be teratogenic in animals, with only limited human data, and its use is not generally recommended in pregnancy. Verapamil is considered safer than diltiazem and could be used as a second-line drug.153,543

14.2.2 Electrical cardioversion

Electrical cardioversion should be the first choice when arrhythmias are haemodynamically unstable. Cardioversion seems safe in all phases of pregnancy as it does not compromise foetal blood flow, and has low risk of inducing foetal arrhythmias or initiating pre-term labour.539 The foetal heart rate should be routinely controlled after cardioversion.

14.2.3 Catheter ablation

Catheter ablation should be postponed to the second trimester if possible, but may be necessary in the case of drug-refractory and poorly tolerated tachycardia. It should then be performed at an experienced centre using non-fluoroscopic electroanatomical mapping and catheter navigation systems.556 Catheter ablation of recurrent, drug-refractory AVNRT, AVRT, focal AT, and CTI-dependent atrial flutter has been successful during pregnancy.550 552

15 Tachycardia-induced cardiomyopathy

15.1 Definition

Tachycardia-induced cardiomyopathy (TCM), or more accurately arrhythmia-induced cardiomyopathy, is a reversible cause of impaired LV function due to persistent tachycardia or very frequent ventricular premature beats that can lead to HF and death. The incidence of TCM is unknown but has been reported in all age groups, from foetuses to the elderly.

15.2 Mechanism

The syndrome was initially described with PJRT, but we now know that any chronic cardiac arrhythmia may cause TCM. Incessant AVRTs due to septal APs, rapid AF, idiopathic VT, AT, and persistent ectopic beats are best described.196,233,526,557 563 In patients aged <18 years, focal AT is the commonest cause.408

Rapid pacing in animal models induces cytoskeletal changes and remodelling of the extracellular matrix attributed to abnormal calcium cycling, increased catecholamines, decreased beta-1 adrenergic receptor density, oxidative stress, depletion of myocardial energy stores, and myocardial ischaemia due to increased heart rate.559,564 Endomyocardial biopsy specimens from patients with TCM exhibit features distinct from those of other types of cardiomyopathy, including deranged cardiomyocyte and mitochondrial morphology, and macrophage-dominated cardiac inflammation.565 However, it has not been fully established how the majority of patients with frequent premature ventricular contractions have a benign course, whereas <30% of them may develop cardiomyopathy.566

Recommendations for the therapy of supraventricular tachycardia in patients with suspected or established heart failure due to tachycardiomyopathy

b.p.m. = beats per minute; ECG = electrocardiogram; HFrEF = heart failure with reduced ejection fraction; LV = left ventricular; SVT = supraventricular tachycardia; TCM = tachycardiomyopathy.

aClass of recommendation. bLevel of evidence.

In TCM, LV function frequently improves after 3 months of restoration of a normal heart rate. In IST, beta-blockers are indicated. Catheter ablation is indicated when TCM is due to another SVT. When the tachycardia itself cannot be ablated, AV nodal ablation