Results:

The final study population consisted of 716 patients (mean age [± standard deviation] 53.5 ± 14.3 years, 469 men [65.5%]), with a clinical and imaging diagnosis of DCM confirmed by CMR. The majority of patients were in New York Heart Association (NYHA) class I (n = 300, 41.9%) or II (n = 277, 38.7%) at enrollment, reflecting the ambulatory status of the patients in this cohort. Of 716 subjects enrolled, 577 (80.6%) were in NYHA class I/II, and 83 (11.6%) had TTNtv. Patients with TTNtv were younger at enrollment (49.0 vs. 54.1 years, p = 0.002) and had lower indexed left ventricular mass (5.1 g/m² reduction, p_adjusted = 0.03) compared to patients without TTNtv. The study investigators found no difference in biventricular ejection fraction between TTNtv ± groups. Overall, 12.9% (78 of 604) of patients met the primary endpoint (median follow-up 3.9 years, interquartile range 2.0-5.8), including 9 of 71 patients with TTNtv (12.7%) and 69 of 533 (12.9%) without. There was no difference in the composite primary outcome of cardiovascular death, heart failure, or arrhythmic events for patients with or without TTNtv (adjusted HR for primary endpoint, 0.92; 95% confidence interval, 0.45-1.87; p = 0.8). The results from the unadjusted and adjusted HR for TTNtv on the primary endpoint were very similar (unadjusted HR, 0.85; p = 0.64; adjusted HR, 0.92; p = 0.8).