Left Ventricular Noncompaction and Coronary Artery Disease: An Unexpected Combination

Abstract

A 51-year-old man without cardiac risk factors was referred to the hospital after a complete left bundle block was discovered on an electrocardiogram; he had a 6-month history of fatigue and mild exertional dyspnea. Transthoracic echocardiogram showed a spongiform appearance of the left ventricle, with prominent hypertrabeculations in lateral and apical walls (Fig. 1A and B). The left ventricle was dilated and hypokinetic (diastolic diameter, 70 mm; ejection fraction, 25%).Severe stenosis (90%) of both the middle tract of the left anterior descending artery and the first diagonal branch was detected by coronary angiography (Fig. 2). Lesions were treated with angioplasty and drug-eluting stent implantation. Cardiac magnetic resonance imaging confirmed the diagnosis of left ventricular noncompaction (LVNC) (Fig. 3A–D).Left ventricular noncompaction is a primary cardiomyopathy of genetic origin1 that may cause congestive heart failure. Concomitant coronary artery disease (CAD) is uncommon, even more so in a patient without cardiac risk factors.A theoretical explanation of this finding might be that the compaction of intertrabecular recesses in the left ventricular myocardium occurs simultaneously with the development of the coronary vasculature between 12 and 18 weeks' gestation.2The anomalous origin of coronary arteries and coronary fistulae have previously been described together with LVNC in isolated case reports in the literature.The co-occurrence of LVNC and CAD has been described only a few times before,3–7 and prior literature on LVNC with congestive heart failure does not report any association with acquired CAD.The presented case shows a peculiar association relevant for future reference in prospective studies to be done in cases of LVNC with cardiomyopathy.The evidence of significant coronary stenosis in combination with LVNC without documented dyslipidemia has led to the hypothesis of a common genetic involvement for myocardial compaction and coronary endothelium development. This speculation is bolstered by the identification of a family with familial CAD and LVNC.8In vitro and in the developing mouse heart, deletion of the Ino80 chromatin remodeler in vascular endothelial cells prevents ventricular compaction. This correlates with scarce coronary vascularization: Ino80 deletion results in a defect in coronary vessel formation, which means coronary arteries develop to become significantly smaller than normal.9 Arbustini et al10 provided an updated list of other genes that are associated with LVNC.Therefore, LVNC is a morphogenetic defect that occurs at the site and time of embryologic development of the coronary arteries (intramyocardial section) that could potentially affect the biology of coronary arteries and increase the risk of early development of CAD.In conclusion, whether the association of CAD with LVNC is coincidental is a question that needs further research. This report contributes to the case recording and opens the prospects for the possibility of some association in patients with LVNC cardiomyopathy.