Originally published by 2 Minute Medicine® (view original article). Reused on AccessMedicine with permission.

1. Nearly 20% of participants with unexplained sudden cardiac death carried pathogenic or likely pathogenic variants of cardiomyopathies and arrhythmia syndromes.

Evidence Rating Level: 2 (Good)

Genetic testing allows for diagnosing inheritable cardiac diseases in unexplained sudden cardiac death (SCD). However, it is currently unknown the degree to which pathogenic or likely pathogenic (P/LP) variants of inherited cardiomyopathies (CMs) and arrhythmia syndromes contribute to SCD in White and Black adults in the U.S. This genetic association study of 683 White and Black adults who passed away due to unexplained SCD were initially reviewed. A total of 413 participants had acceptable DNA data for genetic sequencing between January 1995 and December 2015 (median [IQR] age at death = 41 [29 to 48] years, 62.7% male, 50.4% Black). A total of 38 arrythmia genes and 30 CM genes were sequenced and curated as P/LP. A total of 18.4% of those with unexplained SCD had variants considered P/LP for arrhythmia and CM genes. Approximately 12.6% had 49 P/LP CM variants, 5.3% had 23 P/LP arrhythmia variants, and 0.5% had P/LP variants for both arrhythmia and CM. More specifically, 45 patients (10.9%) had 41 P/LP variants for hypertrophic CM, 11 patients (2.7%) had 9 P/LP variants for dilated CM, and 11 patients (2.7%) had 10 P/LP variants for long QT syndromes. White individuals were as likely to have P/LP variants as Black individuals and no significant difference was found in heart and clinical characteristics between those with and without P/LP variants. Overall, this study suggests that up to 20% of participants with unexplained SCD carried P/LP variants, such that genetics may contribute to many of these cases.

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