Characteristics and Outcomes of Gene-Elusive Dilated Cardiomyopathy

The study examines patients with dilated cardiomyopathy (DCM) in whom genetic testing did not identify pathogenic variants. Genetic mutations are found in approximately one-third of DCM patients, leaving the majority without a genetic diagnosis. The research compared 423 patients without identified mutations with patients carrying mutations in LMNA and TTN genes. Among patients without prior severe arrhythmias, the primary endpoint (end-stage heart failure or malignant ventricular arrhythmia) occurred in 8.5% of gene-elusive patients, 35.9% with LMNA mutations, and 11% with TTN mutations. Gene-elusive patients had similar risk to those with TTN mutations. A subgroup of gene-elusive patients with LBBB (left bundle branch block) showed low risk of complications and fewer arrhythmias.