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type=\u0022text\/css\u0022 rel=\u0022stylesheet\u0022 href=\u0022\/\/d282kpwvnogo5m.cloudfront.net\/sites\/default\/files\/advagg_css\/css__ce2QY63WIanKyr8eSq7eavr1XQRRmFD6ZSmwpyJi8lM__zXwFqpqmxrZOXXcd_TpBQpjuELbmIP9wBR5UuTDWAO4__YJWWMMdfCJuAFm5cUEp88OsodhO3ZA-2lzRfoBsSlk4.css\u0022 media=\u0022all\u0022 \/\u003E\n\u003Clink rel=\u0027stylesheet\u0027 type=\u0027text\/css\u0027 href=\u0027\/sites\/all\/modules\/contrib\/panels\/plugins\/layouts\/onecol\/onecol.css\u0027 \/\u003E\u003C\/head\u003E\u003Cbody\u003E\u003Cdiv class=\u0022panels-ajax-tab-panel panels-ajax-tab-panel-sageoa-tab-art\u0022\u003E\u003Cdiv class=\u0022panel-display panel-1col clearfix\u0022 \u003E\n  \u003Cdiv class=\u0022panel-panel panel-col\u0022\u003E\n    \u003Cdiv\u003E\u003Cdiv class=\u0022panel-pane pane-highwire-markup\u0022 \u003E\n  \n      \n  \n  \u003Cdiv class=\u0022pane-content\u0022\u003E\n    \u003Cdiv class=\u0022highwire-markup\u0022\u003E\u003Cdiv xmlns=\u0022http:\/\/www.w3.org\/1999\/xhtml\u0022 id=\u0022content-block-markup\u0022 xmlns:xhtml=\u0022http:\/\/www.w3.org\/1999\/xhtml\u0022\u003E\u003Cdiv class=\u0022article fulltext-view \u0022\u003E\u003Cspan class=\u0022highwire-journal-article-marker-start\u0022\u003E\u003C\/span\u003E\u003Cdiv class=\u0022section abstract\u0022 id=\u0022abstract-1\u0022\u003E\u003Ch2\u003ESummary\u003C\/h2\u003E\n            \u003Cp id=\u0022p-1\u0022\u003ESudden cardiac death (SCD) is a leading cause of death in the United States (amounting to 1 death every 80 seconds, or 450,000 deaths annually), with \u0026gt;50% of these events having a genetic etiology [Behr ER et al. \u003Cem\u003EEur Heart J\u003C\/em\u003E 2008]. There are several syndromes that are associated with SCD in the young, including congenital long QT syndrome, hypertrophic cardiomyopathy, arrhythmic right ventricular dysplasia, Brugada syndrome, and cathecholamine polymorphic ventricular tachycardia. This article discusses ways to identify these high-risk syndromes and current clinical approaches to SCD prevention in the young.\u003C\/p\u003E\n         \u003C\/div\u003E\u003Cul class=\u0022kwd-group\u0022\u003E\u003Cli class=\u0022kwd\u0022\u003ECardiology Clinical Trials\u003C\/li\u003E\u003Cli class=\u0022kwd\u0022\u003EPrevention \u0026amp; Screening Genomics\u003C\/li\u003E\u003C\/ul\u003E\u003Cp id=\u0022p-2\u0022\u003ESudden cardiac death (SCD) is a leading cause of death in the United States (amounting to 1 death every 80 seconds, or 450,000 deaths annually), with \u0026gt;50% of these events having a genetic etiology [Behr ER et al. \u003Cem\u003EEur Heart J\u003C\/em\u003E 2008]. There are several syndromes that are associated with SCD in the young, including congenital long QT syndrome (LQTS), hypertrophic cardiomyopathy (HCM), arrhythmic right ventricular dysplasia (ARVD), Brugada syndrome (BrS), and cathecholamine polymorphic ventricular tachycardia (CPVT). Kent Stephenson, MD, Huntington Hospital, Huntington, New York, USA, discussed ways to identify these high-risk syndromes and current clinical approaches to SCD prevention in the young.\u003C\/p\u003E\u003Cp id=\u0022p-3\u0022\u003EHCM is the major cause of SCD among athletes and people aged \u226430 years in the United States. It is the most common inherited cardiac disorder, with mutations occurring primarily within the cardiac sarcomere, particularly involving the \u03b2-myosin heavy chain (\u003Ca id=\u0022xref-fig-1-1\u0022 class=\u0022xref-fig\u0022 href=\u0022#F1\u0022\u003EFigure 1\u003C\/a\u003E) [Keren A et al. \u003Cem\u003ENature\u003C\/em\u003E 2008; Spirito P et al. \u003Cem\u003EN Engl J Med\u003C\/em\u003E 1997]. HCM is characterized by unexplained thickening of the heart, and presentation varies from asymptomatic to severe limitation. Overall, mutation carriers tend to be younger, have greater left ventricular hypertrophy, and have a reverse curvature septal morphology (p\u0026lt;0.001) [Binder J et al. \u003Cem\u003EMayo Clinic Proc\u003C\/em\u003E 2006]. Calcium channel blockers, \u03b2-blockers, pacemakers, and implantable defibrillators are viable treatment options for HCM. However, in patients with obstructive symptoms, septal myomectomy is preferred over alcohol septal ablation (ASA), as ASA is associated with less favorable long-term outcomes [ten Cate FJ et al. \u003Cem\u003ECirc Heart Fail\u003C\/em\u003E 2010].\u003C\/p\u003E\u003Cdiv id=\u0022F1\u0022 class=\u0022fig pos-float  odd\u0022\u003E\u003Cdiv class=\u0022highwire-figure\u0022\u003E\u003Cdiv class=\u0022fig-inline-img-wrapper\u0022\u003E\u003Cdiv class=\u0022fig-inline-img\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/10\/7\/11\/F1.large.jpg?width=800\u0026amp;height=600\u0026amp;carousel=1\u0022 title=\u0022Cardiac Sarcomere.\u0022 class=\u0022fragment-images colorbox-load\u0022 rel=\u0022gallery-fragment-images-135449462\u0022 data-figure-caption=\u0022Cardiac Sarcomere.\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003E\u003Cimg class=\u0022fragment-image\u0022 alt=\u0022Figure 1.\u0022 src=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/10\/7\/11\/F1.medium.gif\u0022\/\u003E\u003C\/a\u003E\u003C\/div\u003E\u003C\/div\u003E\u003Cul class=\u0022highwire-figure-links inline\u0022\u003E\u003Cli class=\u00220 first\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/10\/7\/11\/F1.large.jpg?download=true\u0022 class=\u0022highwire-figure-link highwire-figure-link-download\u0022 title=\u0022Download Figure 1.\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EDownload figure\u003C\/a\u003E\u003C\/li\u003E\u003Cli class=\u00221\u0022\u003E\u003Ca href=\u0022http:\/\/d282kpwvnogo5m.cloudfront.net\/content\/spmdc\/10\/7\/11\/F1.large.jpg\u0022 class=\u0022highwire-figure-link highwire-figure-link-newtab\u0022 target=\u0022_blank\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EOpen in new tab\u003C\/a\u003E\u003C\/li\u003E\u003Cli class=\u00222 last\u0022\u003E\u003Ca href=\u0022\/highwire\/powerpoint\/11411\u0022 class=\u0022highwire-figure-link highwire-figure-link-ppt\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EDownload powerpoint\u003C\/a\u003E\u003C\/li\u003E\u003C\/ul\u003E\u003C\/div\u003E\u003Cdiv class=\u0022fig-caption attrib\u0022\u003E\u003Cspan class=\u0022fig-label\u0022\u003EFigure 1.\u003C\/span\u003E \n            \u003Cp id=\u0022p-4\u0022 class=\u0022first-child\u0022\u003ECardiac Sarcomere.\u003C\/p\u003E\n         \u003Cq class=\u0022attrib\u0022 id=\u0022attrib-1\u0022\u003ECopyright \u00a9 1997 Massachusetts Medical Society. All rights reserved.\u003C\/q\u003E\u003Cdiv class=\u0022sb-div caption-clear\u0022\u003E\u003C\/div\u003E\u003C\/div\u003E\u003C\/div\u003E\u003Cp id=\u0022p-5\u0022\u003EBrS is a syndrome that is associated with SCD that often stems from genetic mutations of the SCN5A gene (which regulates the sodium channel), among others. The BrS phenotype is most commonly found in males aged 30 to 40 years with malignant arrhythmias and a history of syncope. BrS can be identified by the presence of coved- or saddleback-shaped ST-segment elevation in ECG leads V1 through V3, complete or incomplete right bundle branch block (RBBB), or T-wave inversion, but there are BrS mimics that may contribute to ST-segment elevation in the right precordial leads that should be considered [Wilde et al. \u003Cem\u003ECirculation\u003C\/em\u003E 2002]. Potential treatments for BrS include quinidine to prevent recurrent syncope, isuprel to treat ventricular electrical storm, and implantable defibrillators for treatment of ventricular tachycardia\/fibrillation and prophylaxis of sudden cardiac death. LQTS is characterized by delayed repolarization of individual action potentials and ECG, potentially resulting in QT interval prolongation and subsequent tachyarrhythmias [Roden DM et al. \u003Cem\u003EJ Cardiovasc Electrophysiol\u003C\/em\u003E 1999]. The most common LQTS genotype that is associated with sudden cardiac arrest at age \u0026lt;40 years is LQT1, though LQTS patients maintain a high risk for life-threatening cardiac events even after age 40. \u03b2-blockers are effective for treatment of LQTS, particularly among patients with LQT1 and LQT2 genotypes (p\u0026lt;0.001) [Moss AJ et al. \u003Cem\u003ECirculation\u003C\/em\u003E 2000].\u003C\/p\u003E\u003Cp id=\u0022p-6\u0022\u003ECatecholaminergic polymorphic ventricular tachycardia (CPVT) is a genetically transmitted cardiac ion channel disorder with an extremely high risk of SCD. If untreated, approximately 50% of individuals will present with a cardiac event that is possibly lethal by the age of 30 years. First recognized in 1975, this disorder involves mutations that lead to loss of calcium homeostasis in the heart, resulting in malignant arrhythmias.\u003C\/p\u003E\u003Cp id=\u0022p-7\u0022\u003EThe most common symptom is syncope, usually during periods of emotional or exertional stress. Syncope most often appears during the first or second decade of life. It is important to distinguish this from LQTS, since \u03b2-blocker therapy in individuals with this syndrome is less effective. In addition, the cardinal finding of prolongation of the QT interval that is seen in LQTS is absent in this disorder [Liu N et al. \u003Cem\u003EProgress in Cardiovascular Diseases\u003C\/em\u003E 2008].\u003C\/p\u003E\u003Cp id=\u0022p-8\u0022\u003EARVD is a genetically determined disease of the heart muscle that is associated with arrhythmia, heart failure, and SCD. It is thought to be most common cause of SCD in the young in European countries. Unfortunately, SCD is often the first clinical manifestation of ARVD, especially among young people who are engaged in strenuous activity. While ARVD is often characterized by intramyocardial RV fatty infiltration, as seen on MRI, Dr. Stephenson cautions that reliance on this diagnostic indicator alone is not sufficient. Therefore, it is important to determine the diagnosis of ARVD, based on the composite of a number of possible findings, including ECG abnormalities (T-wave inversion in V1 to V3, RBBB, and\/or epsilon wave), right ventricular structural abnormalities that are seen on imaging, abnormal myocardial biopsy, positive family history, and genetic testing. No one criterion is robust enough to adequately diagnose ARVD with confidence.\u003C\/p\u003E\u003Cp id=\u0022p-9\u0022\u003EDetecting an increased risk of SCD in young patients is a clinical challenge, and often this risk is not detected until an event occurs, at which point it may be too late. However, there are various syndromes that may serve as early indicators of SCD risk. Thus, identifying these predictive markers is crucial to early detection and risk reduction. Recognizing the ECG footprints of these disorders is paramount to making a diagnosis in the asymptomatic individual. Genetic testing may also provide valuable prognostic and diagnostic data, as genetic mutations play a large role in SCD in the young.\u003C\/p\u003E\u003Cul class=\u0022copyright-statement\u0022\u003E\u003Cli class=\u0022fn\u0022 id=\u0022copyright-statement-1\u0022\u003E\u00a9 2010 MD Conference Express\u003C\/li\u003E\u003C\/ul\u003E\u003Cspan class=\u0022highwire-journal-article-marker-end\u0022\u003E\u003C\/span\u003E\u003C\/div\u003E\u003Cspan id=\u0022related-urls\u0022\u003E\u003C\/span\u003E\u003C\/div\u003E\u003Ca href=\u0022http:\/\/mdc.sagepub.com\/content\/10\/7\/11.abstract\u0022 class=\u0022hw-link hw-link-article-abstract\u0022 data-icon-position=\u0022\u0022 data-hide-link-title=\u00220\u0022\u003EView Summary\u003C\/a\u003E\u003C\/div\u003E  \u003C\/div\u003E\n\n  \n  \u003C\/div\u003E\n\u003C\/div\u003E\n  \u003C\/div\u003E\n\u003C\/div\u003E\n\u003C\/div\u003E\u003Cscript type=\u0022text\/javascript\u0022 src=\u0022http:\/\/mdc.sagepub.com\/sites\/all\/modules\/highwire\/highwire\/plugins\/highwire_markup_process\/js\/highwire_figures.js?nzmpqp\u0022\u003E\u003C\/script\u003E\n\u003Cscript type=\u0022text\/javascript\u0022 src=\u0022http:\/\/mdc.sagepub.com\/sites\/all\/modules\/highwire\/highwire\/plugins\/highwire_markup_process\/js\/highwire_openurl.js?nzmpqp\u0022\u003E\u003C\/script\u003E\n\u003C\/body\u003E\u003C\/html\u003E"}