Subtle Heart Abnormalities Seen in FSHD

Although it’s long been known that some muscular dystrophies, such as Duchenne, Becker and myotonic, almost always affect the heart muscle, it’s been thought that others, such as facioscapulohumeral MD (FSHD), spare this important organ.

But recently, researchers at the University of Pisa in Italy have found that at least some people with FSHD have subtle cardiac abnormalities that might set the stage for more serious problems later on.

Fabio Gletta and colleagues, who published their report in the June issue of Neuromuscular Disorders, found that the 24 FSHD-affected participants they studied had more evidence of reduced function in the left ventricle (lower heart chamber) and of abnormal cardiac muscle cell electrical activity than did the 24 non-FSHD control subjects they also examined.

However, the participants had no symptoms of heart disease, and their problems didn’t reveal themselves on traditional EKG testing or even the usual type of echocardiogram. (Special testing was done in this study.)

The investigators say they believe that additional factors, or “triggers,” are required for significant cardiac rhythm abnormalities to develop in these subtly affected patients.

Their main findings are that the patients with FSHD had indices of abnormal electricity-like signaling in the muscle layer of the heart and that, while this subtle type of cardiac abnormality wasn’t related to the severity of skeletal muscle function, it was correlated with the size of the FSHD-related genetic defect on chromosome 4.

They suggest further studies to establish the “real clinical and prognostic value of these subclinical [below symptom threshold] myocardial abnormalities.”