Cardiac involveent in type 1 myotonic dystrophy.

Myotonic dystrophy is a multisystem disorder in which cardiac involvement is common, particularly in conduction tissue. Its severity and symptoms vary, and so careful monitoring is required and a permanent pacemaker may need to be implanted. The aim of the study was to evaluate cardiac alterations and to correlate them with genetic (CTG expansion) and neurological data. Of the 46 patients studied, 80.4% presented asymptomatic cardiac conduction abnormalities but only one had impaired global systolic function, despite 32.6% having changes in left ventricular segmental contractility. Left ventricular noncompaction was found in 8 patients. Patients with greater CTG expansion had more severe neurological involvement and conduction abnormalities, and those with greater neurological disability had also more significant conduction tissue involvement.