CORRESPONDENCE: LETTER TO THE EDITOR
Reply
Domenico Corrado, MD, PhD*,
Cristina Basso, MD, PhD,
Maurizio Schiavon, MD,
Antonio Pelliccia, MD and
Gaetano Thiene, MD
* Department of Cardiac, Thoracic and Vascular Sciences, University of Padua Medical School, Via Giustiniani, 2, Padua 35121, Italy (Email: domenico.corrado{at}unipd.it).
We appreciate the interest of Dr. van der Werf and colleagues in our review (1). Their comments provide an opportunity to further clarify some aspects concerning appropriate strategies for sudden death prevention. The majority of conditions carrying risk of arrhythmic cardiac arrest in young people and athletes are genetically determined diseases with an autosomal dominant pattern of inheritance. Universal evaluation of the general population for inherited heart diseases is not currently feasible, because of the prohibitive costs and the limited diagnostic accuracy of both clinical and genetic evaluation. A reasonable alternative strategy is to target high-risk subgroups (1,2). Patients with cardiac symptoms, such as syncope or pre-syncope, are the first group that needs accurate cardiologic assessment. However, most inherited cardiomyopathies (including ion channel diseases) show a silent clinical course that might lead to arrhythmic cardiac arrest in the absence of warning disabling symptoms and ventricular dysfunction (1,3). Because the individuals at risk are unlikely to be identified on the basis of spontaneous symptoms, strategies for prevention of sudden death rely on programs of actively searching for high-risk subjects. These prevention strategies include: 1) pre-participation screening of competitive athletes who show a 3-fold increase of the relative risk of sudden cardiac death compared with their nonathletic counterparts; and 2) cascade screening of relatives of sudden cardiac death victims or probands with a inherited heart disease, who have a 50% chance of inheriting the gene defect and the potentially malignant clinical phenotype. The current evidence is that pre-participation electrocardiographic evaluation of young competitive athletes is effective in identifying athletes with potentially lethal cardiovascular disease and actually saves lives, although no data on the efficacy of clinical cascade screening for sudden death prevention are available. At the present time, systematic molecular genetic screening for inherited heart diseases is impractical because it is time-consuming, costly, and—particularly—lacks accuracy given that many disease-causing genes remain to be discovered. Instead, a selective genetic screening of family members of a proband who has been identified with a causative mutation is feasible and offers clear advantages over clinical screening. Genotyping facilitates cascade screening, because it allows for definitive reassurance of true gene-negative family members and focuses prevention strategies on proven gene-carriers. Clinical manifestations of inherited heart diseases are usually preceded by a long "pre-clinical" phase, and cardiac arrest often occurs in previously asymptomatic young adults and competitive athletes. All efforts should be made to identify and manage younger affected family members before life-threatening ventricular arrhythmias occur. These efforts are justified by the recognition that early diagnosis and timely therapy, predominantly by implantable defibrillator, provides life-saving protection (3). Although we agree with the comments that a nationwide clinical and genetic screening for inherited heart diseases is warranted, we believe that pre-participation evaluation of young competitive athletes and familial cascade screening should not be considered mutually exclusive—rather, they should interact synergistically to achieve early (pre-symptomatic) identification of individuals affected by inherited cardiomyopathies at risk of sudden cardiac death.
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1. Corrado D, Basso C, Schiavon M, Pelliccia A, Thiene G. Pre-participation screening of young competitive athletes for prevention of sudden cardiac death J Am Coll Cardiol 2008;52:1981-1989.[Abstract/Free Full Text]2. Sen-Chowdhry S, McKenna WJ. Sudden cardiac death in the young: a strategy for prevention by targeted evaluation Cardiology 2006;105:196-206.[CrossRef][Web of Science][Medline] 3. Corrado D, Thiene G. Arrhythmogenic right ventricular cardiomyopathy/dysplasia: clinical impact of molecular genetic studies Circulation 2006;113:1634-1637.[Free Full Text]
Related Article
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The Relationship Between Pre-Participation Screening of Young Competitive Athletes and Family Screening
- Christian van der Werf, Irene M. van Langen, and Arthur A.M. Wilde
J. Am. Coll. Cardiol. 2009 53: 2309.
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