Improving Detection of Familial Dilated Cardiomyopathy by Systematic Screening

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