Left ventricular noncompaction (LVNC) represents arrest of the normal myocardial 
compaction process and results in the persistence of multiple prominent 
ventricular trabeculations and deep intertrabecular recesses. LVNC can be 
classified into 2 forms: isolated LVNC in the absence of other cardiac anomalies 
and non-isolated LVNC associated with congenital heart disease. The clinical 
presentation and the natural history of LVNC are highly variable, ranging from 
no symptoms to congestive heart failure, arrhythmias, and systemic 
thromboemboli. LVNC is genetically heterogeneous and can be inherited as an 
autosomal dominant or X-linked recessive disorder. It is also linked to 
mutations in several genes, encoding the sarcomeric proteins, such as myosin 
heavy chain 7 (MYH7). MYH7 encodes the β-myosin heavy chain, expressed in the 
cardiac muscle. The operative indication for patients with non-isolated LVNC is 
unclear. Here, we report the first successful case of surgical repair of a 
ventricular septal defect (VSD) in an infant with non-isolated LVNC associated 
with a novel MYH7 mutation. This mutation leads to the substitution of 7 amino 
acid residues (671-677) in the actin-binding region of the protein. After the 
VSD operation, the patient's congestive heart failure and pulmonary hypertension 
improved. His condition has remained stable for 18 months with pharmacotherapy 
comprising diuretics, an angiotensin converting enzyme inhibitor, and a 
β-blocker. Although the postsurgical observational period was short, the 
findings indicate that LVNC mutation analyses may facilitate surgical decisions 
and help predict clinical courses.