Titin‐truncating variants are associated with heart failure events in patients with left ventricular non‐compaction cardiomyopathy

BACKGROUND: Titin‐truncating variants (TTNtv) have been recognized as the most prevalent genetic cause of dilated cardiomyopathy. However, their effects on phenotypes of left ventricular non‐compaction cardiomyopathy (LVNC) remain largely unknown. HYPOTHESIS: The presence of TTNtv may have an effect on the phenotype of LVNC. METHODS: TTN was comprehensively screened by targeted sequencing in a cohort of 83 adult patients with LVNC. Baseline and follow‐up data of all participants were collected. The primary endpoint was a composite of death and heart transplantation. The secondary endpoint was heart failure (HF) events, a composite of HF‐related death, heart transplantation, and HF hospitalization. RESULTS: Overall, 13 TTNtv were identified in 13 patients, with 9 TTNtv located in the A‐band of titin. There was no significant difference in baseline characteristics between patients with and without TTNtv. During a median follow‐up of 4.4 years, no significant difference in death and heart transplantation between the two groups was observed. However, more HF events occurred in TTNtv carriers than in non‐carriers (P = 0.006). Multivariable analyses showed that TTNtv were associated with an increased risk of HF events independent of sex, age, and baseline cardiac function (hazard ratio: 3.25, 95% confidence interval: 1.50‐7.01, P = 0.003). Sensitivity analysis excluding non‐A‐band TTNtv yielded similar results, but with less strength. CONCLUSIONS: The presence of TTNtv may be a genetic modifier of LVNC and confer a higher risk of HF events among adult patients. Studies of larger cohorts are needed to confirm our findings.