Unclassified cardiomyopathies in neuromuscular disorders

Unclassified cardiomyopathies (CMPs) include left ventricular hypertrabeculation or noncompaction (LVHT) and Takotsubo syndrome (TTS). Unclassified CMPs are frequently associated with noncardiac disease, including neuromuscular disorders (NMDs). This review aims at summarizing and discussing recent findings concerning the association of NMDs with unclassified CMPs.

Literature search using the database PubMed from 1966 to June 2013 was performed.

LVHT has been described in association with dystrophinopathies, myotonic dystrophies, zaspopathies, laminopathies, dystrobrevinopathies, oculopharyngeal muscular dystrophy, tropomyosin-1 mutations, multiminicore disease, Danon disease, mitochondrial disorders, myoadenylate deaminase deficiency, Pompe's disease, glycogen storage disease-IV, fatty acid oxidation disorder, Barth syndrome, ryanodine receptor mutation, inclusion body myopathy, dystrophic epidermolysis bullosa, Charcot-Marie-Tooth neuropathy, hereditary cobolamine deficiency, beta-thalassemia, poliomyelitis, and Friedreich ataxia. Takotsubo syndrome has been described in association with myasthenia gravis, amyotrophic lateral sclerosis, Guillain-Barre syndrome, rhabdomyolysis, mitochondrial disorder, hypokalemia-related myopathy, syndrome malin, hereditary sensorimotor neuropathy, Beals syndrome, polymyalgia rheumatica, and unclassified myopathy. It is important for treating physicians to know about these associations because treatment and outcome of LVHT, including artificial ventilation, are determined by the presence or absence of an NMD. There are also indications that LVHT in NMDs favors the development of TTS.

LVHT and TTS may be associated with NMDs. The pathogenetic link between unclassified CMPs and NMDs remains elusive. Outcome of LVHT and treatment of TTS are additionally determined by the presence or absence of an NMD.