Abstract
Syncope is a clinical measure of increased risk for sudden death in the genetic diseases being considered in this chapter. Distinguishing a syncopal episode that is due to an arrhythmic cause from benign causes of syncope can be difficult. Nonetheless, the clinician needs to make that distinction as the therapy for arrhythmic syncope is entirely different from a case of syncope due to an autonomic cause.
In the patient with known hypertrophic cardiomyopathy (HCM), syncope is a major predictor of sudden death. Other well described risk factors contribute to the overall risk of sudden death. By employing all clinical modalities of treatment in hypertrophic cardiomyopathy patients the risk of death due to complications of the disease, including sudden death, can be reduced to less than 1% per year.
Arrhythmogenic right ventricular cardiomyopathy (ARVC) patients who present with syncope are candidates for an implantable cardioverter defibrillator (ICD) in the ACC/AHA/HRS syncope guidelines. The ESC guidelines recommend an ICD only if the syncope is shown to be due to a ventricular arrhythmia. Implantable loop recorders are recommended for ARVC syncope patients without ventricular tachycardia. Precise risk stratification is difficult in the ARVC patient.
The long QT syndrome (particularly Types 1 and 2) has benefited from large clinical reports in the literature and risk stratification is clear. The patient with long QT (>460 ms) is treated with a beta blocker even if asymptomatic. If syncope occurs an ICD is recommended by both European and ACC/AHA/HRS guidelines.
Brugada syndrome may be both difficult to diagnose and difficult to risk stratify. A sudden cardiac death (SCD) survivor is a candidate for an ICD. Syncope alone without a cardiac arrest is a class IIa recommendation for an ICD in the AHA/ACC/HRS guidelines whereas the ESC guidelines recommend a loop recorder. Genetic testing and electrophysiology studies are not recommended as adding to clinical features for risk stratification.
Catecholaminergic polymorphic tachycardia (CPVT) patients who have a cardiac arrest or multiple syncopal spells without a cardiac arrest are recommended for an ICD. Flecainide can be given to reduce frequent defibrillator shocks. Genetic testing is useful in making the diagnosis of CPVT.
This is a preview of subscription content, log in via an institution.
Buying options
Tax calculation will be finalised at checkout
Purchases are for personal use only
Learn about institutional subscriptionsReferences
Brignole M, Moya A, de Lange FJ, Deharo JC, Elliott PM, Fanciulli A, Fedorowski A, Furlan R, Kenny RA, Martín A, ESC Scientific Document Group, et al. 2018 ESC guidelines for the diagnosis and management of syncope. Eur Heart J. 2018;39(21):1883–948. https://doi.org/10.1093/eurheartj/ehy037.
Shen WK, Sheldon RS, Benditt DG, Cohen MI, Forman DE, Goldberger ZD, Grubb BP, Hamdan MH, Krahn AD, Link MS, Writing Committee Members, et al. 2017 ACC/AHA/HRS guideline for the evaluation and management of patients with syncope: a report of the American College of Cardiology/American Heart Association Task Force on Clinical Practice Guidelines and the Heart Rhythm Society. Heart Rhythm. 2017;14(8):e155–217. https://doi.org/10.1016/j.hrthm.2017.03.004.
Priori SG, Blomström-Lundqvist C, Mazzanti A, Blom N, Borggrefe M, Camm J, Elliott PM, Fitzsimons D, Hatala R, Hindricks G, ESC Scientific Document Group, et al. 2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC). Eur Heart J. 2015;36(41):2793–867. https://doi.org/10.1093/eurheartj/ehv316.
Køber L, Thune JJ, Nielsen JC, Haarbo J, Videbæk L, Korup E, Jensen G, Hildebrandt P, Steffensen FH, Bruun NE, DANISH Investigators, et al. Defibrillator implantation in patients with nonischemic systolic heart failure. N Engl J Med. 2016;375(13):1221–30. https://doi.org/10.1056/NEJMoa1608029.
Olshansky B, Poole JE, Johnson G, Anderson J, Hellkamp AS, Packer D, Mark DB, Lee KL, Bardy GH, SCD-HeFT Investigators. Syncope predicts the outcome of cardiomyopathy patients: analysis of the SCD-HeFT study. J Am Coll Cardiol. 2008;51(13):1277–82. https://doi.org/10.1016/j.jacc.2007.11.065.
Ruwald MH, Okumura K, Kimura T, Aonuma K, Shoda M, Kutyifa V, Ruwald AC, McNitt S, Zareba W, Moss AJ. Syncope in high-risk cardiomyopathy patients with implantable defibrillators: frequency, risk factors, mechanisms, and association with mortality: results from the multicenter automatic defibrillator implantation trial-reduce inappropriate therapy (MADIT-RIT) study. Circulation. 2014;129(5):545–52. https://doi.org/10.1161/CIRCULATIONAHA.113.004196.
Elliott PM, Poloniecki J, Dickie S, Sharma S, Monserrat L, Varnava A, Mahon NG, McKenna WJ. Sudden death in hypertrophic cardiomyopathy: identification of high risk patients. J Am Coll Cardiol. 2000;36(7):2212.
Maron BJ, Rowin EJ, Casey SA, Link MS, Lesser JR, Chan RH, Garberich RF, Udelson JE, Maron MS. Hypertrophic cardiomyopathy in adulthood associated with low cardiovascular mortality with contemporary management strategies. J Am Coll Cardiol. 2015;65(18):1915–28. https://doi.org/10.1016/j.jacc.2015.02.061.
Al-Khatib SM, Stevenson WG, Ackerman MJ, Bryant WJ, Callans DJ, Curtis AB, Deal BJ, Dickfeld T, Field ME, Fonarow GC, et al. 2017 AHA/ACC/HRS guideline for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death. Circulation. 2018;138(13):e272–391. https://doi.org/10.1161/CIR.0000000000000549.
Maron BJ, Casey SA, Chan RH, Garberich RF, Rowin EJ, Maron MS. Independent assessment of the European society of cardiology sudden death risk model for hypertrophic cardiomyopathy. Am J Cardiol. 2015;116(5):757–64. https://doi.org/10.1016/j.amjcard.2015.05.047.
Wang W, Orgeron G, Tichnell C, Murray B, Crosson J, Monfredi O, Cadrin-Tourigny J, Tandri H, Calkins H, James CA. Impact of exercise restriction on arrhythmic risk among patients with arrhythmogenic right ventricular cardiomyopathy. J Am Heart Assoc. 2018;7(12):e008843. https://doi.org/10.1161/JAHA.118.008843.
Schwartz PJ, Moss AJ, Vincent GM, Crampton RS. Diagnostic criteria for the long QT syndrome. An update. Circulation. 1993;88(2):782–4.
Moss AJ, Schwartz PJ, Crampton RS, Tzivoni D, Locati EH, MacCluer J, Hall WJ, Weitkamp L, Vincent GM, Garson A Jr, et al. The long QT syndrome. Prospective longitudinal study of 328 families. Circulation. 1991;84(3):1136–44.
Ackerman MJ, Priori SG, Dubin AM, Kowey P, Linker NJ, Slotwiner D, Triedman J, Van Hare GF, Gold MR. Beta-blocker therapy for long QT syndrome and catecholaminergic polymorphic ventricular tachycardia: are all beta-blockers equivalent? Heart Rhythm. 2017;14(1):e41–4. https://doi.org/10.1016/j.hrthm.2016.09.012.
Schwartz PJ, Priori SG, Spazzolini C, Moss AJ, Vincent GM, Napolitano C, Denjoy I, Guicheney P, Breithardt G, Keating MT, et al. Genotype-phenotype correlation in the long-QT syndrome: gene-specific triggers for life-threatening arrhythmias. Circulation. 2001;103(1):89–95.
Probst V, Veltmann C, Eckardt L, Meregalli PG, Gaita F, Tan HL, Babuty D, Sacher F, Giustetto C, Schulze-Bahr E, et al. Term prognosis of patients diagnosed with Brugada syndrome: results from the FINGER Brugada Syndrome Registry. Circulation. 2010;121(5):635–43. https://doi.org/10.1161/CIRCULATIONAHA.109.887026.
Priori SG, Napolitano C, Tiso N, Memmi M, Vignati G, Bloise R, Sorrentino V, Danieli GA. Mutations in the cardiac ryanodine receptor gene (hRyR2) underlie catecholaminergic polymorphic ventricular tachycardia. Circulation. 2001;103(2):196–2.
Author information
Authors and Affiliations
Corresponding author
Editor information
Editors and Affiliations
Rights and permissions
Copyright information
© 2020 Springer Nature Switzerland AG
About this chapter
Cite this chapter
Cannom, D.S. (2020). Unexplained Syncope in Patients with High Risk of Sudden Death. In: Brignole, M., Benditt, D. (eds) Syncope. Springer, Cham. https://doi.org/10.1007/978-3-030-44507-2_22
Download citation
DOI: https://doi.org/10.1007/978-3-030-44507-2_22
Published:
Publisher Name: Springer, Cham
Print ISBN: 978-3-030-44506-5
Online ISBN: 978-3-030-44507-2
eBook Packages: MedicineMedicine (R0)