Structural and functional cardiac changes in myotonic dystrophy type 1: a cardiovascular magnetic resonance study
1 Department of Neurology, Maastricht University Medical Centre, PO box 5800, Maastricht, AZ 6202, The Netherlands
2 Department of Cardiology, Maastricht University Medical Centre, Maastricht, The Netherlands
3 Department of Radiology, Maastricht University Medical Centre, Maastricht, The Netherlands
4 Department of Clinical Genetics, Maastricht University Medical Centre, Maastricht, The Netherlands
5 Department of Neurology, Spaarne Hospital, Hoofddorp, The Netherlands
6 Department of Cardiology, Academic Medical Center, Amsterdam, The Netherlands
Journal of Cardiovascular Magnetic Resonance 2012, 14:48 doi:10.1186/1532-429X-14-48Published: 24 July 2012
Myotonic dystrophy type 1 (MD1) is a neuromuscular disorder with potential involvement of the heart and increased risk of sudden death. Considering the importance of cardiomyopathy as a predictor of prognosis, we aimed to systematically evaluate and describe structural and functional cardiac alterations in patients with MD1.
Eighty MD1 patients underwent physical examination, electrocardiography (ECG), echocardiography and cardiovascular magnetic resonance (CMR). Blood samples were taken for determination of NT-proBNP plasma levels and CTG repeat length.
Functional and structural abnormalities were detected in 35 patients (44%). Left ventricular systolic dysfunction was found in 20 cases, left ventricular dilatation in 7 patients, and left ventricular hypertrophy in 6 patients. Myocardial fibrosis was seen in 10 patients (12.5%). In general, patients had low left ventricular mass indexes. Right ventricular involvement was uncommon and only seen together with left ventricular abnormalities. Functional or structural cardiac involvement was associated with age (p = 0.04), male gender (p < 0.001) and abnormal ECG (p < 0.001). Disease duration, CTG repeat length, severity of neuromuscular symptoms and NT-proBNP level did not predict the presence of myocardial abnormalities.
CMR can be useful to detect early structural and functional myocardial abnormalities in patients with MD1. Myocardial involvement is strongly associated with conduction abnormalities, but a normal ECG does not exclude myocardial alterations. These findings lend support to the hypothesis that MD1 patients have a complex cardiac phenotype, including both myocardial and conduction system alteration.