Isolated Noncompaction of the Myocardium
A Rarity or Missed Diagnosis?
A 31-year-old man presented to the emergency department with central chest tightness, shortness of breath, and presyncope. His admission ECG was abnormal (Figure 1), with inferior and lateral Q waves, left ventricular hypertrophy, repolarization changes in leads II, III, AVF, and V4 to V6, and nonspecific ST elevation in V1 to V3. A physical examination was unremarkable except for a fourth heart sound. Baseline blood studies showed mildly elevated troponin and creatine kinase-MB levels and hypercholesterolemia. A cardiac ultrasound showed the upper limit of normal wall thickness and normal valvular flows, biventricular size, and function. Cardiac catheterization revealed a mildly abnormal contraction of the anterobasal wall of the left ventricle and normal epicardial coronary vessels. Cardiac magnetic resonance imaging was performed to help exclude myocardial/pericardial disease.
Magnetic resonance documented intramyocardial recesses of the inferior and anterobasal left ventricular (LV) wall. These recesses were in communication with the LV lumen (Figure 2, A and B). In addition, prominent trabeculation extended into the LV cavity (Figure 3). Ventricular mass, size, and systolic function were normal. There was no evidence of myocardial hyperenhancement after gadolinium injection. Serology was normal.
These appearances are consistent with myocardial noncompaction, a congenital disorder of endomyocardial embryogenesis. This example is less florid than cases detailed in the limited number of echo and pathology series currently published and, in fact, would have been missed by ultrasound criteria. A diagnosis of noncompaction has important implications because of the need for familial screening and the possible association with other cardiac anomalies and/or muscle disorders, progressive LV dysfunction, risk of systemic embolism, and life-threatening arrhythmias. Techniques such as magnetic resonance imaging may improve detection rates and provide new insights into the prevalence, spectrum, and natural course of this potentially not-so-rare condition.
This work was supported by Coronary Artery Disease Research Association (CORDA; Marian Silcock Fellowship).
The editor of Images in Cardiovascular Medicine is Hugh A. McAllister, Jr, MD, Chief, Department of Pathology, St Luke’s Episcopal Hospital and Texas Heart Institute, and Clinical Professor of Pathology, University of Texas Medical School and Baylor College of Medicine.
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