"Concealed cardiomyopathy" as a cause of previously unexplained sudden cardiac arrest

Int J Cardiol. 2021 Feb 1:324:96-101. doi: 10.1016/j.ijcard.2020.09.031. Epub 2020 Sep 12.

Abstract

Background: Genetic heart disease is a common cause of sudden cardiac arrest (SCA) in the young and those without an ischaemic precipitant. Identifying a cause of SCA in these patients allows for targeted care and family screening. Current guidelines recommend limited, phenotype-guided genetic testing in SCA survivors where a specific genetic condition is suspected and genetic testing is not recommended in clinically-idiopathic SCA survivors.

Objective: To investigate the diagnostic utility of broad, multi-phenotype genetic testing in clinically-idiopathic SCA survivors.

Methods: Clinically-idiopathic SCA survivors underwent analysis of genes known to be associated with either cardiomyopathy or primary arrhythmia syndromes, following referral to a specialised genetic heart disease clinic in Sydney, Australia between 1997 and 2019. Comprehensive review of clinical records, investigations and re-appraisal of genetic data according to current variant classification criteria was performed.

Results: In total, 22% (n = 8/36) of clinically-idiopathic SCA survivors (mean age 36.9 ± 16.9 years, 61% male) had a disease-causing variant identified on broad genetic testing. Of these, 7 (88%) variants resided in cardiomyopathy-associated genes (ACTN2, DES, DSP, MYBPC3, MYH7, PKP2) despite structurally normal hearts or sub-diagnostic structural changes at the time of arrest, so-called "concealed cardiomyopathy". Only one SCA survivor had a variant identified in a channelopathy associated gene (SCN5A).

Conclusion: Extended molecular analysis with multi-phenotype genetic testing can identify a "concealed cardiomyopathy", and increase the diagnosis rate for clinically-idiopathic SCA survivors.

Keywords: Clinically-idiopathic; Concealed cardiomyopathy; Genetic testing; Multi-phenotype genetic testing; Sudden cardiac arrest.

Publication types

  • Review

MeSH terms

  • Adult
  • Arrhythmias, Cardiac
  • Australia
  • Cardiomyopathies* / diagnosis
  • Cardiomyopathies* / epidemiology
  • Cardiomyopathies* / genetics
  • Death, Sudden, Cardiac / epidemiology
  • Death, Sudden, Cardiac / etiology
  • Female
  • Heart Arrest*
  • Humans
  • Male
  • Middle Aged
  • Young Adult