Background and objectives Left ventricular hypertrabeculation/noncompaction (LVHT) is a cardiac abnormality frequently associated with neuromuscular disorders (NMD). The data about long-term prognosis of patients with LVHT are controversial. Aim of the study in a cohort of LVHT patients was to assess the long-term prognosis regarding mortality, cardiac and neuromuscular comorbidity. Methods and results In 86 patients LVHT was diagnosed echocardiographically between June 1995 and December 2004 (21 female, mean age 52 ± 14, range 14–94 years). All patients underwent a baseline cardiologic investigation and were invited for a neurologic investigation. A specific NMD was diagnosed in 21, a NMD of unknown etiology in 33, the neurologic investigation was normal in 13 and 19 patients refused. During a mean follow-up of 51 months (range 3–106 months) the mortality rate was 5.3%/year. Predictors for an increased mortality were increased age ( p = 0.0134), presence of NMD ( p = 0.0324), exertional dyspnoea ( p = 0.0329), edema ( p = 0.0049), heart failure ( p = 0.0048), left anterior hemiblock ( p = 0.0078) and a left ventricular fractional shortening < 25% ( p = 0.0648). Conclusion The mortality of LVHT in adult patients depends on cardiac and neurologic comorbidity. Predictors for mortality are increased age, neuromuscular disorder, heart failure, left ventricular dilatation and systolic dysfunction.