Diagnostic yield and predictive value on left ventricular remodelling of genetic testing in dilated cardiomyopathy

Aims: We assessed the diagnostic yield of genetic testing and the relationship of left ventricular (LV) reverse remodelling (LVRR) with the presence of DNA pathogenic (P) or likely pathogenic (LP) variants in patients with dilated cardiomyopathy (DCM). Methods and results: From 680 outpatients followed at the Heart Failure Outpatient Clinic of our institution, we selected subjects with a diagnosis of DCM as defined by LV ejection fraction (LVEF) ≤40% and LV dilatation not explained by coronary artery disease or other causes. All patients were offered genetic investigation of 42 disease-associated DCM genes with next-generation sequencing. Seventy patients fulfilled the definition of DCM and 66 underwent genetic investigation. We identified 18 P/LP variants in 16 patients, with a diagnostic yield of 24%. The most common variants were truncating TTN variants (n = 7), followed by LMNA (n = 3), cytoskeleton Z-disc (n = 3), ion channel (n = 2), motor sarcomeric (n = 2), and desmosomal (n = 1) genes. After a median follow-up of 53 months (inter-quartile range 20-111), patients without P/LP variants exhibited higher systolic and diastolic blood pressure, lower plasma brain natriuretic peptide levels, and a larger extent of LVRR, as reflected by the increase in LVEF (+14% vs. +1%, P = 0.0008) and decrease in indexed LV end-diastolic diameter (-6.5 vs. -2 mm/m2 , P = 0.03) compared with patients with P/LP variants. Conclusions: Our results confirm the high diagnostic yield of genetic testing in selected DCM patients and suggest that identification of P/LP variants in DCM portends poorer LVRR in response to guideline-directed medical therapy.