Assessment of cardiac involvement in myotonic muscular dystrophy by T1 mapping on magnetic resonance imaging.
BACKGROUND
Patients with myotonic muscular dystrophy (DM) are at risk for atrioventricular block and left ventricular (LV) dysfunction. Noninvasive detection of diffuse myocardial fibrosis may improve disease management in this population.


OBJECTIVE
To define functional and postcontrast myocardial T1 time cardiac magnetic resonance characteristics in patients with DM.


METHODS
Thirty-three patients with DM (24 with type 1 and 9 with type 2) and 13 healthy volunteers underwent cardiac magnetic resonance for the assessment of LV indices and the evaluation of diffuse myocardial fibrosis by T1 mapping. The association of myocardial T1 time with electrocardiogram abnormalities and LV indices was examined among patients with DM.


RESULTS
Patients with DM had lower end-diastolic volume index (68.9 mL/m(2) vs 60.3 mL/m(2); P = .045) and cardiac index (2.7 L/min/m(2) vs 2.33 L/min/m(2); P = .005) and shorter myocardial T1 time (394.5 ms vs 441.4 ms; P < .0001) than did control subjects. Among patients with DM, there was a positive association between higher T1 time and LV mass index (2.2 ms longer per g/m(2); P = .006), LV end-diastolic volume index (1.3 ms longer per mL/m(2); P = .026), filtered QRS duration (1.2 ms longer per unit; P = .005), and low-amplitude (<40 mcV) late-potential duration (0.9 ms longer per unit; P = .01). Using multivariate random effects regression, each 10-ms increase in myocardial T1 time of patients with type 1 DM was independently associated with 1.3-ms increase in longitudinal PR and QRS intervals during follow-up.


CONCLUSIONS
DM is associated with structural alterations on cardiac magnetic resonance. Postcontrast myocardial T1 time was shorter in patients with DM than in controls, likely reflecting the presence of diffuse myocardial fibrosis.
Radiology and Imaging Sciences, Clinical Center, and National Institute of Biomedical Imaging and Bioengineering, National Institutes of Health, Bethesda, MD 20892, USA.
Evrim B
EB
Turkbey
Neville
N
Gai
João A C
JA
Lima
Rob J
RJ
van der Geest
Kathryn R
KR
Wagner
Gordon F
GF
Tomaselli
David A
DA
Bluemke
Saman
S
Nazarian
D000328:Adult; D009202:Cardiomyopathies / Q000473:pathology*; D016022:Case-Control Studies; D003287:Contrast Media; D018450:Disease Progression; D004562:Electrocardiography; D005260:Female; D019786:Gadolinium DTPA; D006801:Humans; D019028:Magnetic Resonance Imaging, Cine / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009223:Myotonic Dystrophy / Q000473:pathology*; D012307:Risk Factors
D003287:Contrast Media; D019786:Gadolinium DTPA