Adult Patient With Isolated Noncompaction of Ventricular Myocardium
A 55-year-old woman was admitted to our hospital because of congestive heart failure despite full medical therapy. She had been diagnosed as having and was treated for cardiomyopathy of unknown cause during an extended period. She had no familial history of cardiovascular diseases or sudden cardiac death. Echocardiograms revealed severely reduced left ventricular (LV) contraction, severe mitral regurgitation, thickened myocardium with prominent trabeculations, and deep intertrabecular recesses in the apical and LV lateral walls (Figure 1). 99mTc methoxyisobutylisonitrile (MIBI) scintigraphy showed decreased uptake in the LV inferior wall, posterior wall, and apex. 123Iodine metaiodobenzylguanidine (MIBG) scintigraphy also showed decreased uptake and increased washout rate in the same regions (Figure 2).
The patient then underwent cardiac resynchronization therapy by atrial synchronized biventricular pacing. Although she achieved improved walking distance and quality of life for a while, she was rehospitalized for heart failure. A few months later, she had a cardiac arrest at home and died despite resuscitative efforts.
An autopsy revealed LV dilatation and prominent trabeculation in the lateral wall, the posterior wall, and the apex of the LV (Figure 3). The thickness ratio between the compacted and the noncompacted layer was 0.2. Histological findings indicated moderate subendocardial fibrosis. Endomyocardial thickening and subendocardial fibroelastosis were not evident. Other anatomic disorders of the heart were not detected.
In conclusion, diagnosis of isolated noncompaction of ventricular myocardium can be made based on echocardiography; however, the correct diagnosis is often missed because of a lack of knowledge about this uncommon disease. It should be always considered in adult patients, as well as in younger patients with dilated cardiomyopathy or hypertrophic cardiomyopathy.