THEMED ARTICLE y Congenital

Commentary

ICDs in adults with congenital heart disease: an overview Expert Review of Cardiovascular Therapy Downloaded from informahealthcare.com by Washington University Library on 01/05/15 For personal use only.

Expert Rev. Cardiovasc. Ther. 11(12), 1591–1593 (2013)

Sunita J Ferns Author for correspondence: University of North Carolina, College of Medicine, Chapel Hill, USA [email protected]

Gerald Naccarelli Penn State College of Medicine, PA, USA

Advances in cardiac surgery have led to a growing population of adult congenital heart disease (ACHD) patients. Rhythm disturbances in these patients are due to the inherent cardiac anomaly, complex physiology or are acquired after surgery. Sudden cardiac death (SCD) remains a leading cause of mortality in ACHD and arrhythmias are an important risk factor for sudden death. An implantable cardioverter-defibrillator (ICD) is an established therapy for primary and secondary prevention of SCD due to ventricular arrhythmias in the adult population, however there are no universally accepted guidelines for ACHD patients. This editorial aims to explore the unique considerations of ICD implantation in patients with ACHD. Magnitude of the problem

An estimated one million ACHD patients live in the USA alone [1,2]. The incidence of SCD has been estimated to be approximately one per 1000 patient-years, about 25–100times greater than in the general population [3]. The incidence of supraventricular tachycardia (SVT) and ventricular tachycardia (VT) in Tetralogy of Fallot (TOF) patients alone is 34% and 9%, respectively with an estimate of sudden death at 100 per year nationally or 2% per decade [4]. Older atriopulmonary Fontan have an estimated 50% incidence of atrial tachycardia within a decade of palliation with SCD accounting for 16% of deaths. In a recent series, 13% of patients with Fontan circulations had pacemakers or ICDs [5]. The reported prevalence of SCD in patients with

transposition of great arteries (TGA) and an atrial switch operation is up to 15% [6]. Pathophysiology

Surgical scars and long standing hemodynamic changes in repaired ACHD are the primary contributors to longterm electrical sequelae. Scar formation is secondary to chronic fibrosis or surgical lines create conduction isthmuses for re-entry circuits. Long-term pacing due to congenital or surgically induced atrioventricular block or bundle branch block further contributes to cardiac dyssynchrony. Scarring and stretch can lead to changes in ionic properties, shortening of the action potential and increased excitability contributing to arrhythmias [7,8]. Abnormal electrical connections such as rapidly conducting accessory pathways and twin AV nodes can also cause rapidly conducting atrial arrhythmias, heart failure and sudden death [9,10]. Intra-atrial reentrant tachycardia (IART) is the most common type of supraventricular arrhythmia in CHD. IART can conduct rapidly and in the setting of an already compromised systemic right ventricle (RV), lead to a secondary VT and SCD [11,12]. The focus of device therapy is maintaining chronotropic competence, resynchronization and preventing sudden death. Indications for ICD therapy

Since the absolute risk of SCD in ACHD is still largely unknown, accurate risk assessment of individual patients is challenging. There are no guidelines, as such, for ICD implant in

KEYWORDS: adult congenital heart disease • arrhythmia • implantable cardioverter-defibrillator inappropriate shock • sudden cardiac death

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10.1586/14779072.2013.839213

Ó 2013 Informa UK Ltd

ISSN 1477-9072

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Expert Review of Cardiovascular Therapy Downloaded from informahealthcare.com by Washington University Library on 01/05/15 For personal use only.

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Ferns & Naccarelli

ACHD potentially at risk of SCD. However, implant indications are similar to that for patients without congenital heart disease and include a history of sustained VT or cardiac arrest, inducible VT, syncopal or near syncopal events, left ventricular (LV) dysfunction and QRS duration [13]. For patients, in which, the ventricle at risk is not a LV, use of ICDs for primary prevention is much less clear. Risk stratification for these groups of patients is complex and evolving, and scores have been proposed for disease specific conditions like repaired TOF and TGA [14&16]. Though the occurrence of RV dysfunction contributes to increased risk of sudden death in patients with TOF, recent reports have shown that LV dysfunction is an indicator of SCD and predicted appropriate ICD therapies [15]. Sequential changes of QRS duration and of ventricular function may add to identify high-risk patients [13]. Indications for cardiac resynchronization therapy

In patients with single ventricles or a systemic RV, standard antiheart failure medications such as ACE inhibitors and ARBs are often ineffective [17,18]. As with primary prevention ICDs, in this population, indications for cardiac resynchronization therapy (CRT) are also unclear and data from clinical trials in adults with ischemic or dilated cardiomyopathy are often extrapolated to this group. In patients with a systemic LV, a prolonged QRS of 120 ms or higher on maximal pharmacologic therapy and NYHA class 3–4 symptoms, CRT may be beneficial in improving symptoms, cardiac function and survival. Special considerations

In contrast to patients with a structurally normal heart who require ICDs for coronary heart disease, cardiomyopathies or channelopathies, patients with CHD often have abnormal intracardiac anatomy, difficulties with access and altered hemodynamics. Due to a high incidence of sinus node dysfunction and arrhythmias a dual chamber ICD may be preferable to a single chamber device. Alternately presence of limited venous access, may pose a problem when considering multiple transvenous leads. In patients with a Fontan circulation with no transvenous access to the ventricle, subcutaneous arrays, epicardial and/or subcutaneous ICD leads is an option [19]. Optimal electrode configuration remains empirical. In the presence of persistent intracardiac shunts, transvenous leads are contraindicated due to the risk of paradoxical embolism. Diseased RV states, tricuspid and pulmonary regurgitation can increase the risk of lead dislodgement and failure. Pacemaker-induced dyssynchrony is a complication of life long pacemaker utilization in patients with additional conduction abnormalities. Steps to minimize dyssynchrony included alternate site pacing, pacing algorithms that increase AV delays to favor intrinsic conduction and atrial-based programming options with backup ventricular pacing. In patients with systemic RVs or a univentricular heart tachycardia induced cardiomyopathy may develop more rapidly than in a biventricular circulation. 1592

Complications

The immediate procedure-related complication rate is usually higher given the unusual cardiac anatomy and high-risk nature of some of these cardiac lesions. Moreover these patients tend to be relatively young and active compared to the majority of non-congenital adult patients receiving ICDs. The incidence of lead failure is up to 20%, which is higher than that in the general population. Lead failure can be especially challenging to manage due to the high risk associated with reintervention. The incidence of inappropriate shocks is also high with SVT accounting for 41% of shocks in a recent cohort [20]. The presence of TOF was associated with less appropriate shocks, compared with patients with other congenital heart defects. Careful attention to programming of discriminators and antiarrhythmic adjustments is a key to management. The impact of ICD therapy on the quality of life in this population may warrant specific considerations especially given the preexisting psychosocial problems associated with the underlying cardiac diagnosis in severe ACHD. Anxiety, depression and problems with low self-esteem can be a significant problem especially with inappropriate shocks. A meta-analysis of nine ICD intervention studies showed that interventions such as cognitive-behavioral therapy, cardiac education and rehabilitative approaches are typically most effective in reducing anxiety and improving exercise capacity in ICD patients. Future of ACHD & ICDs

It is important to understand that the ACHD population is constantly evolving. Changes in surgical techniques in the last few decades are reflected as changing population of ACHD. The relative number of patients with an arterial switch operation will overtake patients with an atrial switch repair in the coming decade. Arterial switch patients have a morphologic LV supporting the systemic circulation and experience has thus far shown that they tend to do better than atrial switch patients with a systemic RV. Myocardial ischemia due to replantation of coronaries is a risk not only in the early postoperative period but also several years out of surgery. More patients being followed will have an extracardiac Fontan compared to the atriopulmonary Fontan and the incidence of atrial arrhythmias is expected to be less in this group of patients. Current survival rates for complex heart disease are excellent and in the last decade the use of ICDs have contributed toward increased survival. Conclusion

ICDs play an important role in the management of SCD in ACHD. Current consensus is that survivors of sudden cardiac death are candidates for ICD therapy however selection of patients for secondary prevention remains a challenge. Identified risk factors have a high sensitivity, however low specificity and event rate contribute to a low predictive power. Technical challenges during implant and a higher complication rate mandate careful selection and planning. Expert Rev. Cardiovasc. Ther. 11(12), (2013)

ICDs in adults with congenital heart disease: an overview

Financial & competing interests disclosure

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This

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1

2

3

Webb G, Williams R et al. 32nd bethesda conference: care of the adult with congenital heart disease. J. Am. Coll. Cardiol. 37, 1161–1198 (2001). Marelli AJ, Mackie AS, Ionescu-Ittu R, Rahme E, Pilote L. Congenital heart disease in the general population: changing prevalence and age distribution. Circulation 115, 63–72 (2007). Silka MJ, Hardy BG, Menashe VD, Morris CD. A population-based prospective evaluation of risk of sudden cardiac death after operation for common congenital heart defects. J. Am. Coll. Cardiol.. 32(, 245–251 (1998).

4

Lam W, Friedman RA. Electrophysiology issues in adult congenital heart disease. Methodist Debakey Cardiovasc. J. 7, 13–17 (2011).

5

Stephenson EA, Lu M, Berul C et al. Arrhythmias in a contemporary Fontan cohort: prevalence and clinical associations in a multicenter crosssectional study. J. Am. Coll. Cardiol. 56, 890–896 (2010).

6

Janousek J, Paul T, Luhmer I, Wilken M, Hruda J, Kallfelz HC. Atrial baffle procedures for complete transposition of the great arteries: natural course of sinus node dysfunction and risk factors for dysrhythmias and sudden death. Z. Kardiol. 83, 933–938 (1994).

7

Ravelli F, Allessie M. Effects of atrial dilatation on refractory period and vulnerability to atrial fibrillation in the

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includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties. No writing assistance was utilized in the production of this manuscript.

isolated Langendorff-perfused rabbit heart. Circulation. 96, 1686–1695 (1997).

References 8

9

10

11

12

13

Commentary

Iyer V, Heller V, Armoundas AA. Altered spatial calcium regulation enhances electrical heterogeneity in the failing canine left ventricle: implications for electrical instability. J. Appl. Physiol. 112, 944–955 (2012). Sreeram N, Wren C. Supraventricular tachycardia in infants: response to initial treatment. Arch. Dis. Child. 65, 127–129 (1990). Wang YS, Scheinman MM, Chien WW et al. Patients with supraventricular tachycardia presenting with aborted sudden death: incidence, mechanism and long-term follow-up. J. Am. Coll. Cardiol. 18, 1711–1719 (1991). Kammeraad JA, van Deurzen CH, Sreeram N et al. Predictors of sudden cardiac death after Mustard or Senning repair for transposition of the great arteries. J. Am. Coll. Cardiol. 44, 1095–102 (2004). Khairy P, Landzberg MJ, Lambert J, O’Donnell CP. Long-term outcomes after the atrial switch for surgical correction of transposition: a meta-analysis comparing the Mustard and Senning procedures. Cardiol. Young14, 284–292 (2004). Koyak Z, Harris L, de Groot JR et al. Sudden cardiac death in adult congenital heart disease. Circulation 126, 1944–1954 (2012).

14

Gatzoulis MA, Balaji S, Webber S et al. Risk factors for arrhythmia and sudden cardiac death late after repair of tetralogy of Fallot: a multicentre study. Lancet 356, 975–981 (2000).

15

Khairy P, Harris L, Landzberg M et al. Implantable cardioverterdefibrillators in tetralogy of Fallot. Circulation 117, 363–370 (2008).

16

Schwerzmann M, Salehian O, Harris L et al. Ventricular arrhythmias and sudden death in adults after a Mustard operation for transposition of the great arteries. Eur. Heart J. 30, 1873–1879 (2009).

17

Dore A, Houde C, Chan K et al. Angiotensin receptor blockade and exercise capacity in adults with systemic right ventricles: a multicenter, randomized, placebo-controlled clinical trial. Circulation 112, 2411–2416 (2005).

18

Hechter SJ, Fredriksen PM, Liu P et al. Angiotensin-converting enzyme inhibitors in adults after the Mustard procedure. Am. J. Cardiol. 87, 660-663, A611 (2001).

19

Bardy GH, Smith WM, Hood M et al. An entirely subcutaneous implantable cardioverter-defibrillator. N. Engl. J. Med. 363, 36–44 (2010).

20

Yap SC, Harris L. Sudden cardiac death in adults with congenital heart disease. Expert Rev. Cardiovasc. Ther. 7, 1605–1620 (2009).

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ICDs in adults with congenital heart disease: an overview.

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