Surgical Repair of Left Ventricular Noncompaction in a Patient with a Novel Mutation of the Myosin Heavy Chain 7 Gene

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.