Genetic Causes in Cardiac Arrest Survivors
Fake News or the Real Deal?
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Sudden cardiac death is a tragic and devastating complication of several cardiovascular diseases. In those aged >35 years, the most common underlying cause is coronary artery disease and its sequelae, while under the age of 35 years, genetic heart diseases, such as the inherited cardiomyopathies and primary arrhythmia syndromes, are the predominant causes.1,2 In ≤40% of young sudden cardiac death cases, no cause is identified after a comprehensive postmortem examination.3,4 While the majority of young individuals who suffer a cardiac arrest do not survive the event, a smaller proportion of individuals (≤25%) are cardiac arrest survivors. A common scenario in these cardiac arrest survivors is the absence of a definite clinical phenotype after comprehensive clinical investigation.
See Article by Mellor et al
In this month’s edition of Circulation: Cardiovascular Genetics, Mellor et al5 attempt to define the causes underlying cardiac arrest in survivors who have no clear phenotype using a comprehensive genetic testing approach. Using the landmark CASPER (Cardiac Arrest Survivors with Preserved Ejection Fraction) registry, 174 cardiac arrest survivors underwent genetic testing of 50 to 100 cardiac genes on average. The key finding was that 29 (17%) of cardiac arrest survivors had a pathogenic (disease-causing) mutation identified, of which 60% were in arrhythmia-related genes and 40% in cardiomyopathy-related genes. Prior syncope and a family history of sudden death were independently associated with a positive genetic result.5
The authors of this study need to be commended for their outstanding efforts in trying to define the role of genetic testing in this unique, and tragically, relatively rare cohort of young cardiac arrest survivors. These studies are challenging to perform. Key factors include access to a cohort size large enough to draw meaningful conclusions, collection of all available medical information before, during, and …