Early detection of cardiac involvement in Miyoshi myopathy: 2D strain echocardiography and late gadolinium enhancement cardiovascular magnetic resonance.
BACKGROUND
Miyoshi myopathy (MM) is an autosomal recessive distal myopathy characterized by early adult onset. Cardiomyopathy is a major clinical manifestation in other muscular dystrophies and an important prognostic factor. Although dysferlin is highly expressed in cardiac muscle, the effect of dysferlin deficiency in cardiac muscle has not been studied. We hypothesized that early myocardial dysfunction could be detected by 2D strain echocardiography and late gadolinium enhancement (LGE) cardiovascular magnetic resonance (CMR).


METHODS
Five consecutive MM patients (3 male) in whom we detected the DYSF gene mutation and age-matched healthy control subjects were included. None of the patients had history of cardiac disease or signs and symptoms of overt heart failure. Patients were studied using 2D strain echocardiography and CMR, with 2D strain being obtained using the Automated Function Imaging technique.


RESULTS
All patients had preserved left ventricular systolic function. However, segmental Peak Systolic Longitudinal Strain (PSLS) was decreased in 3 patients. Global PSLS was significantly lower in patients with MM than in control subjects (p = 0.005). Basal anterior septum, basal inferior septum, mid anterior, and mid inferior septum PSLS were significantly lower in patients with MM than in control subjects (P < 0.0001, < 0.0001, 0.038 and 0.003, respectively). Four patients showed fibrosis by LGE. The reduced PSLS lesion detected by 2D strain tended to be in the same area as that which showed fibrosis by LGE.


CONCLUSIONS
Patients with MM showed subclinical involvement of the heart. 2D strain and LGE are sensitive methods for detecting myocardial dysfunction prior to the development of cardiovascular symptoms. The prognostic significance of these findings warrants further longitudinal follow-up.
Choi
E Ryoung
ER
Cardiovascular Imaging Center, Samsung Medical Center, Sungkyunkwan University School of Medicine, 50 Irwon-dong, Gangnam-gu, Seoul, 135-710, Seoul, Republic of Korea.
Park
Sung-Ji
SJ
Choe
Yeon Hyeon
YH
Ryu
Dong Ryeol
DR
Chang
Sung-A
SA
Choi
Jin-Oh
JO
Lee
Sang-Chol
SC
Park
Seung Woo
SW
Kim
Byoung Joon
BJ
Kim
Duk-Kyung
DK
Oh
Jae K
JK
D000328:Adult; D009202:Cardiomyopathies / Q000175:diagnosis* / Q000209:etiology; D016022:Case-Control Studies; D000073939:Dysferlin; D004452:Echocardiography; D005260:Female; D005682:Gadolinium; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008565:Membrane Proteins; D008875:Middle Aged; D009124:Muscle Proteins; D009135:Muscular Diseases / Q000150:complications / Q000175:diagnosis*; D019275:Radiopharmaceuticals
C114839:DYSF protein, human; D000073939:Dysferlin; D008565:Membrane Proteins; D009124:Muscle Proteins; D019275:Radiopharmaceuticals; D005682:Gadolinium