Whole collection based on Evidence

Sudden Cardiac Death in the Young

Hypertrophic cardiomyopathy remains the most common structural cause of SCD in the young, although in some regions of the world, arrhythmogenic right ventricular cardiomyopathy (ARVC) is more prevalent. Myocarditis, congenital heart diseases including coronary artery anomalies, and coronary artery disease are other structural causes of SCD. Structural cardiac abnormalities account for approximately 70% of cases of SCD.

Normal postmortem examination at autopsy including normal histology and negative toxicology testing is present in the remaining 30% of SCD cases, and suggests a primary arrhythmia as the cause of death. Termed sudden arrhythmic death syndrome (SADS), these deaths are due to familial long-QT syndrome (LQTS), catecholaminergic polymorphic ventricular tachycardia (CPVT), Brugada syndrome (BrS), idiopathic ventricular fibrillation, and short-QT syndrome.

Heart Rhythm Society/European Heart Rhythm Association guidelines recommend postmortem genetic testing, also referred to as a molecular autopsy, in SADS cases, if circumstantial evidence points towards a clinical diagnosis of LQTS or CPVT. This includes direct DNA sequencing of the protein coding exons of four genes, i.e., the three major LQTS genes (KCNQ1, KCNH2, SCN5A) and the CPVT gene (RYR2). Mutations in the SCN5A gene also cause BrS.

While initial studies in selected SADS populations reported detection rates for a causative mutation of up to 34%, more recent population-based studies suggest that the detection rate with the four-gene molecular autopsy is more likely to be up to 15–20%.

– See more at: http://www.acc.org/latest-in-cardiology/ten-points-to-remember/2015/03/26/15/19/sudden-cardiac-death-in-the-young?w_nav=LC#sthash.hOO4qzD9.dpuf

Sudden Cardiac Death in the Young: The Molecular Autopsy and a Practical Approach to Surviving Relatives. Eur Heart J 2015;Mar 12:[Epub ahead of print].