Myotonic dystrophy type 1 (DM1) is a neuromuscular disorder in relation with an unstable expansion of CTG repeat. Patients with DM1 are at risk of arrhythmia and conduction disorders. Mortality are mainly related to respiratory failure and sudden death. Patients with DM1 may suffer from obesity, arterial hypertension, diabetes mellitus and sleep apnea. These comorbidities are classically associated with left ventricular diastolic dysfunction (DD) .

The investigators aim to assess the prevalence of left ventricular diastolic dysfunction in patients with myotonic dystrophy type 1 , the distribution of DD grading as well as the long-term prognosis of DM1 patients with a left ventricular diastolic dysfunction.

Inclusion Criteria:

• patients with genetic proven myotonic dystrophy type 1
• who experienced a Doppler- Echocardiography including an assessment of the left ventricular diastolic function

Exclusion Criteria:

• wall motion basal abnormalities
• significant valvular disease

patients with myotonic dystrophy type 1 followed in a tertiary reference center.