Familial Dilated Cardiomyopathy – Enhancing Detection Using Systematic Screening

Abstract

Background: Dilated cardiomyopathy (DCM) is the leading indication for heart transplantation in New Zealand (NZ). The familial subtype (FDCM) is aggressive, presents early, and is implicated in up to 50% of idiopathic DCM (IDCM). Diagnosis requires an affected individual having ≥2 affected close relatives. Adequate family pedigree analysis is diagnostically essential, and screening relatives is imperative as pre-symptomatic therapy improves outcomes. We utilised a validated family history survey to screen our NZ heart transplant population for FDCM more systematically. Methods: Medical records of living heart transplant patients with IDCM or FDCM diagnoses (77/339 patients) were reviewed. Patients were provided our survey via post/email and at clinic visits. We evaluated our 12 question clinical survey's efficacy in obtaining a complete three-generation family history and compared that to information documented in the medical records. Results: Fifty-one (66%) surveys were returned. Complete family history was obtained in 47/51 (92.2%), compared with 10/51 (19.6%) specifically documented in medical records. Responders identified 16 relatives who were also referred for heart transplantation, or who died ≤50 years with cardiomyopathy. The tool diagnosed FDCM in 25/51 (49.0%, with a further 3 possible FDCM), already yielding 6 additional patients not previously diagnosed. The mean age at first presentation of FDCM was 37 years (23 were male, 2 female), compared with 43 years in the IDCM group. Conclusion: Utilising a formal family screening tool improves pedigree analysis ensuring more effective detection of FDCM, which is prevalent in the NZ transplant cohort. Formalised systematic screening has great potential to improve outcomes.