| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
(Circulation. 2001;103:2361.)
© 2001 American Heart Association, Inc.
Clinical Investigation and Reports |
From the National Heart, Lung, and Blood Institute (P.M.S., R.B.), Bethesda, Md; Brigham and Womens Hospital (C.A.), Boston, Mass; Boston University (E.J.B.), Boston, Mass; Case Western Reserve University (R.C.E.), Cleveland, Ohio; Vanderbilt University (A.L.G.), Nashville, Tenn; Hospital Boucicaut, Paris, France (X.J.); University of Pittsburgh (L.H.K.), Pittsburgh, Pa; Southwest Foundation for Biomedical Research (J.W.M.), San Antonio, Texas; Johns Hopkins Medical School (E.M.), Baltimore, Md; Harvard Medical School (J.E.M.), Boston, Mass; University of Pavia (P.J.S.) Pavia, Italy; University of Washington (D.S.S.), Seattle; University of Vermont (R.P.T.), Colchester; University of Rochester (W.Z.), Rochester, NY; and Indiana University (D.P.Z.), Indianapolis.
Correspondence to Peter M. Spooner, PhD, Director, Arrhythmias, Ischemia, and Sudden Cardiac Death, Division of Heart and Vascular Diseases, National Heart, Lung, and Blood Institute, Two Rockledge Center, Suite 9192, 6701 Rockledge Dr, MSC 7940, Bethesda, MD 20892-7940. E-mail PS48J{at}nih.gov
| Abstract |
|---|
|
|
|---|
Key Words: genetics death, sudden arrhythmia tachyarrhythmias epidemiology mortality ion channels
| Introduction |
|---|
|
|
|---|
To explore these issues, the National Heart, Lung, and Blood Institute (NHLBI) convened an Expert Workshop to consider the evidence that new elements of familial association may be involved, to explore etiologies of these relationships, and to provide ideas on how they might best be addressed. This report represents the results of those deliberations. The ideas expressed here represent the views of the participants, not opinions or positions endorsed in any way by the NHLBI. The workshop considered four major questions: (1) What factors contribute to arrhythmia susceptibility? (2) Do new data on familial SCD risks justify a search for additional susceptibility elements? (3) What molecular processes might be involved? and (4) How can new genetic and population investigations help resolve these issues? The major focus of the discussions involved the identification of "susceptibility candidates" most likely to elevate risk of SCD in common cardiac conditions. The approach taken in the discussion that follows is to consider factors that contribute to lethal arrhythmias in rare inherited cardiac conditions and then to explore new evidence on risk factors for SCD in common patient populations.
| Inherited Causes of SCD and Ventricular Arrhythmias |
|---|
|
|
|---|
-subunits
KvLQT1 (LQT-1) and Herg (LQT-2); 2 genes coding the K channel
regulatory ß-subunits, minK (LQT-5) and MiRP1 (LQT-6); and a gene
associated with one form of LQTS, designated LQT-4, of unknown origin
(reviewed in Roden and
Spooner8 ). Most recently,
mutations in the cardiac ryanodine receptor Ca channel gene were
identified in a related form of inherited
tachycardia.9
In addition to the rare, ion channelbased
arrhythmias, occurrence of inherited susceptibility to SCD is
associated with other, less well understood pathologies. Prominent
among these are mutations in contractile, structural, and cytoskeletal
proteins. Familial hypertrophic cardiomyopathies
with a high incidence of SCD have been linked to mutations in at least
9 cardiac sarcomeric proteins (the ß-myosin heavy chain, myosin
binding protein C,
-actin, troponins I and T,
-tropomyosin, the
cardiac essential and regulatory light chains, and titin [reviewed in
Bonne et al10 and Seidman
and Seidman11 ]). Enhanced
SCD has also been reported in inherited dilated
cardiomyopathy to be associated with mutations in
cytoskeletal proteins such as dystrophin, desmin, and
-actin and the
nuclear envelope proteins lamins A and C, with the latter involving
primarily conduction system
disease.12 13
With some of these conditions, there appear to be plausible functional
associations (eg, alterations in Ca handling) between molecular
aberration and electrical performance, whereas with others (eg,
mutations in lamins or
NKX2.514 ) in which there are
overt electrical disturbances, connection with processes that
could affect electrical stability would appear far downstream of the
lesions detected to date. As with LQTS, most of these aberrations have
been thought to reflect effects in the working myocardium,
but defects in sinoatrial or AV node cells and His-Purkinje conduction
may also occur and manifest clinically with symptoms of heart block and
bradyarrhythmias. For other conditions, of which arrhythmogenic
right ventricular cardiomyopathy is a
prime example, genes are just beginning to be identified, but
chromosomal sites, now at least 7 in number, have been mapped and the
incidence of electrical disturbances, as well as extensive
myocardial remodeling, has been well documented. In the first case to
be successfully resolved, a mutation in the structural protein
plakoglobin, a component of adherent intercellular junctions, was
identified in an autosomal recessive form of arrhythmogenic right
ventricular cardiomyopathy, Naxos
disease, but whether this results in altered patterns of cell-cell
conduction has not been
established.15
| SCD: The "Phenotype Problem" |
|---|
|
|
|---|
Phenotypic dissonance with inherited forms of SCD may thus be similar to that encountered with other complex, multigene diseases, such as highly familial forms of hypertension, diabetes, or atherosclerosis, but with little in the way of identification of the specific traits involved. Genetic influences on SCD events are suggested, however, by observations such as the finding that women have a lower overall incidence of SCD than men24 yet also appear more sensitive to drug-induced or LQTS arrhythmias. Such findings may be attributable in part to differences in repolarization parameters that are under hormonal control,25 and it seems likely that other factors are also involved.
Much of the genotype-phenotype problem with arrhythmic diseases also reflects the fact that SCD simply represents a clinical outcome, ie, cardiac arrest, a common mechanism of death, rather than a change in identifiable metabolic, biochemical, or pathological events. As such, it can be the result of various clinical events, and the standard accepted definition of SCD (any near instantaneous, electrically based, cessation of cardiac output in individuals with otherwise uncompromised circulatory function26 ) is, from a mechanistic perspective, as ambiguous a phenotype imaginable. At issue is the differentiation of comorbid conditions from proximal arrhythmogenic events. Until we learn more about the combinations of terminal processes in arrhythmogenesis in different acquired diseases, it seems unlikely a more precise characterization of common high-risk SCD phenotypes, which apply in progressive chronic diseases, will emerge. What may be possible instead is identification of "signature" combinations of particularly destabilizing molecular events that could then help guide prevention efforts. In conjunction with conventional stratification approaches including standard and T-wave alternans, ECG analyses, or ejection fraction, improved SCD phenotyping with new approaches and recognition of new information, for example, on ventricular ectopy,27 could add considerably to our abilities to recognize differing degrees of arrhythmia risk.
| Multiple Elements of SCD Risk |
|---|
|
|
|---|
New studies on conventional risk factors in population-based studies on coronary heart disease, hypertension, atherosclerosis, and other predisposing conditions will also be important in therapy selection. There are now abundant data from large-scale epidemiological studies undertaken over the past 20 years, such as the Framingham Heart Study, the Physicians Health Study, and the Nurses Health Study, as well as others, that are proving quite useful in deciphering heritable arrhythmia susceptibilities. In the past, such approaches have proven most useful in identifying traditional metabolic, behavioral, and dietary risk factors for CAD, such as blood pressure, smoking, gender, diabetes, physical inactivity, and triglyceride, cholesterol, LDL, and HDL levels and ratios, as well as their influence on overall cardiac mortality.28 In many of these studies, however, it has not been possible to determine whether the resulting morbidity and mortality data can be directly associated with an arrhythmic pathology. The work has nevertheless been valuable in identifying relative and absolute risks associated with these elements, and the results have had important public health implications. Algorithms that attempt to extend conventional risk factor prediction studies to assessment of specific individuals and classes of cardiac patients have also been promulgated but appear to be of much more limited value. This reflects many factors, including reliance on population-based "normal values" and the problem that extension of norms to individuals does not generally consider differences in genetic diversity between the groups sampled and those being assessed. Evidence of the unreliability of focusing on only those previously identified risk factors for CAD as a means of reducing premature cardiovascular mortality is, for example, well reflected in the observation that a high percentage of SCDs still occur in individuals with no elevation in currently recognized traditional risk factors.1 New approaches applicable to understanding individual and disease-specific elements of molecular SCD susceptibility are thus likely to play an increasingly significant role in reducing cardiovascular mortality in the future.
| Appendix 1 |
|---|
|
|
|---|
Organizing Committee
Eric A. Boerwinkle, PhD; Jean W. MacCluer, PhD; James
E. Muller, MD; David S. Siscovick, MD; Jeffrey A. Towbin, MD;
and Russell P. Tracy, MD, PhD.
NHLBI Staff
Peter M. Spooner, PhD, and Robin Boineau,
MD.
| Acknowledgments |
|---|
| Footnotes |
|---|
2 The authors listed here provided summary material reflecting contributions from the full group of workshop participants (see Appendix). Dr Spooner was responsible for the manuscript. ![]()
Received November 7, 2000; revision received February 1, 2001; accepted February 16, 2001.
| References |
|---|
|
|
|---|
2.
Uretsky BF,
Thygesen K, Armstrong PW, et al. Acute coronary findings at
autopsy in heart failure patients with sudden death: results from the
Assessment of Treatment with Lisinopril And Survival
(ATLAS) trial. Circulation. 2000;102:611616.
3. Myerburg RJ, Kessler KM, Castellanous A. Epidemiology of sudden cardiac death: population characteristics, conditioning risk factors, and dynamic risk factors. In: Spooner PM, Brown AM, eds. Ion Channels in the Cardiovascular System: Function and Dysfunction. Armonk, NY: Futura Publishing; 1994:1535.
4.
Priori SG, Bahranin
J, Haver RNW, et al. Genetic and molecular basis of cardiac
arrhythmias: impact on clinical management, parts I and II.
Circulation. 1999;99:518528.
5. Keating MT, Sanguinetti MC. Molecular genetic insights into cardiovascular disease. Science. 1996;272:681685.[Abstract]
6. Chen Q, Kirsch GE, Zhang D, et al. Genetic basis and molecular mechanism for idiopathic ventricular fibrillation. Nature. 1998;392:293296.[Medline] [Order article via Infotrieve]
7. Schott JJ, Alshinawi C, Kyndt F, et al. Cardiac conduction defects associate with mutations in SCN5A. Nat Genet. 1999;23:2021.[Medline] [Order article via Infotrieve]
8. Roden DM, Spooner PM. Inherited long QT syndromes: a paradigm for understanding arrhythmogenesis. J Cardiovasc Electrophysiol. 1999;10:16641683.[Medline] [Order article via Infotrieve]
9. Priori SG, Napolitano C, Tiso N, et al. Mutations in the cardiac ryanodine receptor gene (hRyR2) underlie catecholaminergic polymorphic ventricular tachycardia. Circulation. 2000;102:r49r53.
10.
Bonne G, Carrier
L, Richard P, et al. Familial hypertrophic
cardiomyopathy: from mutation to functional
defects. Circ Res. 1998;83:580593.
11. Seidman CE, Seidman JG. Gene mutations that cause familial hypertrophic cardiomyopathy. In: Haber E, ed. Scientific American: Molecular Cardiovascular Medicine. New York, NY: Scientific American; 1995:193210.
12.
Fatkin D, MacRae
C, Sasaki T, et al. Missense mutations in the rod domain of the lamin
a/c gene as causes of dilated cardiomyopathy and
conduction system disease. N Engl
J Med. 1999;341:17151724.
13.
Muchir A, Bonne
G, van der Kooi AJ, et al. Identification of mutations in the gene
encoding lamins A/C in autosomal dominant limb girdle muscular
dystrophy with atrioventricular conduction
disturbances. Hum Mol
Genet. 2000;9:14531459.
14. Benson DW, Silberbich GM, McHugh AK, et al. Mutations in the cardiac transcription factor NKX2.5 affect diverse cardiac developmental pathways. J Clin Invest. 1999;104:15671573.[Medline] [Order article via Infotrieve]
15. Li D, Ahmad F, Gardner MJ, et al. The locus of a novel gene responsible for arrhythmogenic right-ventricular dysplasia characterized by early onset and high penetrance maps to chromosome 10p12-p14. Am J Hum Genet. 2000;66:148156.[Medline] [Order article via Infotrieve]
16. Fatkin D, McConnell BK, Mudd JO, et al. An abnormal Ca2+ response in mutant sarcomere protein-mediated familial hypertrophic cardiomyopathy. J Clin Invest. 2000;106:13511359.[Medline] [Order article via Infotrieve]
17. Wu Y, MacMillan LB, McNeill RB, et al. CaM kinase augments cardiac L-type Ca2+ current: a cellular mechanism for long Q-T arrhythmias. Am J Physiol. 1999;276:H2168H2178.
18.
Schwartz PJ,
Priori SG, Spazzolini C, et al. Genotype-phenotype
correlation in the long-QT syndrome.
Circulation. 2001;103:8995.
19. Watkins H, Rosenzweig A, Hwang D, et al. Characteristics and prognostic implications of myosin missense mutations in familial hypertrophic cardiomyopathy associated with mutations of the beta myosin heavy chain gene. N Engl J Med. 1992;326:11081114.[Abstract]
20.
Nimura H,
Bachinski LL, Sangwatanaroj S, et al. Mutations in the gene for cardiac
myosin-binding protein C and late-onset familial hypertrophic
cardiomyopathy. N
Engl J Med. 1998;338:12481257.
21.
Bezzina C,
Veldkamp MW, van den Berg MP, et al. A single
Na+ channel mutation causing both long-QT
and Brugada syndromes. Circ
Res. 1999;85:12061213.
22.
Priori SG,
Napolitano C, Schwartz PJ. Low penetrance in the long-QT syndrome.
Circulation. 1999;99:529533.
23.
Sesti F, Abbott
GW, Wei J, et al. A common polymorphism associated with
antibiotic-induced cardiac arrhythmia.
Proc Natl Acad Sci
U S A. 2000;97:1061310618.
24.
Schatzkin A,
Cupples LA, Heeran T, et al. Sudden death in the Framingham Heart
Study: differences in incidence and risk factors by sex and
coronary disease status. Am J
Epidemiol. 1984;120:888899.
25. Ebert SN, Liu XK, Woosley RL. Female gender as a risk factor for drug-induced cardiac arrhythmias: evaluation of clinical and experimental evidence. J Womens Health. 1998;7:547557.[Medline] [Order article via Infotrieve]
26.
Hinkle LE, Thaler
HT. Clinical classification of cardiac deaths.
Circulation. 1982;65:457464.
27.
Jouven X, Zureik
M, Desnos M, et al. Long-term outcome in asymptomatic men
with exercise-induced premature ventricular depolarization.
N Engl J Med. 2000;343:826833.
28.
Wilson PW,
DAgostino RB, Levy D, et al. Prediction of coronary heart
disease using risk factor categories.
Circulation. 1998;97:18371847.
This article has been cited by other articles:
![]() |
D. W. Wang, R. R. Desai, L. Crotti, M. Arnestad, R. Insolia, M. Pedrazzini, C. Ferrandi, A. Vege, T. Rognum, P. J. Schwartz, et al. Cardiac Sodium Channel Dysfunction in Sudden Infant Death Syndrome Circulation, January 23, 2007; 115(3): 368 - 376. [Abstract] [Full Text] [PDF] |
||||
![]() |
E. Schulze-Bahr Arrhythmia Predisposition: Between Rare Disease Paradigms and Common Ion Channel Gene Variants J. Am. Coll. Cardiol., October 27, 2006; 48(9_Suppl_A): A67 - A78. [Abstract] [Full Text] [PDF] |
||||
![]() |
Developed in Collaboration With the European Heart, D. P. Zipes, A. J. Camm, M. Borggrefe, A. E. Buxton, B. Chaitman, M. Fromer, G. Gregoratos, G. Klein, A. J. Moss, et al. ACC/AHA/ESC 2006 Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death: A Report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death) J. Am. Coll. Cardiol., September 5, 2006; 48(5): e247 - e346. [Full Text] [PDF] |
||||
![]() |
Writing Committee Members, D. P. Zipes, A. J. Camm, M. Borggrefe, A. E. Buxton, B. Chaitman, M. Fromer, G. Gregoratos, G. Klein, A. J. Moss, et al. ACC/AHA/ESC 2006 guidelines for management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: A report of the American College of Cardiology/American Heart Association Task Force and the European Society of Cardiology Committee for Practice Guidelines (Writing Committee to Develop Guidelines for Management of Patients With Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death) Developed in collaboration with the European Heart Rhythm Association and the Heart Rhythm Society Europace, September 1, 2006; 8(9): 746 - 837. [Full Text] [PDF] |
||||
![]() |
D. J. Milan and C. A. MacRae Animal models for arrhythmias Cardiovasc Res, August 15, 2005; 67(3): 426 - 437. [Abstract] [Full Text] [PDF] |
||||
![]() |
J H Sullivan, A B Schreuder, C A Trenga, S L-J Liu, T V Larson, J Q Koenig, and J D Kaufman Association between short term exposure to fine particulate matter and heart rate variability in older subjects with and without heart disease Thorax, June 1, 2005; 60(6): 462 - 466. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. Josephson and H. J.J. Wellens Implantable Defibrillators and Sudden Cardiac Death Circulation, June 8, 2004; 109(22): 2685 - 2691. [Full Text] [PDF] |
||||
![]() |
C. Bellocq, A. C.G. van Ginneken, C. R. Bezzina, M. Alders, D. Escande, M. M.A.M. Mannens, I. Baro, and A. A.M. Wilde Mutation in the KCNQ1 Gene Leading to the Short QT-Interval Syndrome Circulation, May 25, 2004; 109(20): 2394 - 2397. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. E. Arking, S. S. Chugh, A. Chakravarti, and P. M. Spooner Genomics in Sudden Cardiac Death Circ. Res., April 2, 2004; 94(6): 712 - 723. [Abstract] [Full Text] [PDF] |
||||
![]() |
M. J. Ackerman, D. J. Tester, G. S. Jones, M. L. Will, C. R. Burrow, and M. E. Curran Ethnic Differences in Cardiac Potassium Channel Variants: Implications for Genetic Susceptibility to Sudden Cardiac Death and Genetic Testing for Congenital Long QT Syndrome Mayo Clin. Proc., December 1, 2003; 78(12): 1479 - 1487. [Abstract] [PDF] |
||||
![]() |
D. E. Gutstein, S. B. Danik, J. B. Sereysky, G. E. Morley, and G. I. Fishman Subdiaphragmatic murine electrophysiological studies: sequential determination of ventricular refractoriness and arrhythmia induction Am J Physiol Heart Circ Physiol, August 7, 2003; 285(3): H1091 - H1096. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. P.M Gorgels, C. Gijsbers, J. de Vreede-Swagemakers, A. Lousberg, and H. J.J Wellens Out-of-hospital cardiac arrest-the relevance of heart failure. The Maastricht Circulatory Arrest Registry Eur. Heart J., July 1, 2003; 24(13): 1204 - 1209. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. P. Zipes Less Heart Is More Circulation, May 27, 2003; 107(20): 2531 - 2532. [Full Text] [PDF] |
||||
![]() |
J. Sullivan, N. Ishikawa, L. Sheppard, D. Siscovick, H. Checkoway, and J. Kaufman Exposure to Ambient Fine Particulate Matter and Primary Cardiac Arrest among Persons With and Without Clinically Recognized Heart Disease Am. J. Epidemiol., March 15, 2003; 157(6): 501 - 509. [Abstract] [Full Text] [PDF] |
||||
![]() |
D. M. Roden The problem, challenge and opportunity of genetic heterogeneity in monogenic diseases predisposing to sudden death J. Am. Coll. Cardiol., July 17, 2002; 40(2): 357 - 359. [Full Text] [PDF] |
||||
![]() |
P. M. Spooner and D. P. Zipes Sudden Death Predictors: An Inflammatory Association Circulation, June 4, 2002; 105(22): 2574 - 2576. [Full Text] [PDF] |
||||
![]() |
W. S. Rubenstein and R. I. Lopez-Soler The Genetics of Sudden Death JAMA, October 3, 2001; 286(13): 1636 - 1636. [Full Text] [PDF] |
||||
| ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
|
Circulation Home | Subscriptions | Archives | Feedback | Authors | Help | AHA Journals Home | Search Copyright © 2001 American Heart Association, Inc. All rights reserved. Unauthorized use prohibited. |