Non-Compaction Cardiomyopathy Misdiagnosed as Dilated Cardiomyopathy

Abstract

Introduction: Noncompaction cardiomyopathy is a rare cardiomyopathy, until now, not fully clarified. It is thought to result from an arrest of the compaction of loose myocardial meshwork during foetal development. Diagnosis remains difficult since there are similarities with other cardiac defects, clinical manifestations are non-specific and echocardiographic criteria are not universally accepted. As a consequence diagnosis may be easily missed. We present a clinical case of previously healthy and asymptomatic boy,misdiagnosed as dilated cardiomyopathy. Case presentation: A 13-year-old boy presented with a 2 day of abdominal pain after being hit by his friend. He was previously healthy, referring no prior cardiac or pulmonary complaints. His family history were his father died of gastric cancer at the age of 40, his elder brother died of heart failure when he was 13 years old. Physical examination showed PMI at the sixth intercostal space and anterior axillary line, S3 and a grade III/VI holosystolic murmurs in apical. Liver edge below 2cm the right costal margin. Results: Chest x-ray demonstrated increased heart-thorax index. ECG show right axis deviation, two atrial enlargement, two ventricular hypertropihy, ventricular premature contraction. Holter ECG show sinus tachycardia, iosolated ventricular premature contraction was 17% (25,219), 4 beats fastest run 227bpm. TSH was 1.84 mIU/ml (normal value 0.35-4.94 mIU/ml). HDL-C was 0.75mmol/l. Liver transaminases levels and renal function tests were normal. Carotid and aortic artery Doppler Ultrasound were normal. A echocardiography demonstrated exuberant thickening and trabeculation of the lateral and posterior walls of the apical half of the left ventricle with two distinct myocardial layers: a normal compact (C) epicardium and a thickened non-compact (NC) endocardium. The ratio between NC endocardium and C epicardium >2,2 (measured at end systole in parasternal short axis view). Left ventricle cavity was dilated and presented diffuse hypokinesis and an ejection fraction of 20%. No additional abnormalities were found. These findings were consistent with the diagnosis of Noncompaction cardiomyopathy. A cardiac MS-CT 640 slices was performed which confirmed the diagnosis, revealing numerous proeminent trabeculae and deep intertrabecular recesses and a ratio between NC endocardium and C epicardium >2,2. Discussion: Several diagnostic criteria have been proposed in the literature. In this clinical case diagnosis was primarly established by echocardiography according to the criteria defined by Jenni and colleagues. According to these authors diagnosis is based on the detection of 2 myocardial layers, with a normal compact (C) epicardium and a thickened non-compact (NC) endocardium. They propose a quantitative evaluation by determining the ratio between the 2 layers NC/C ≤2, measured at end systole in parasternal short axis view, to establishe diagnosis. This allows differentiation of the trabeculations of Noncompaction cardiomyopathy from that observed with Dilated cariomyopathy and Hypertropic cardiomyopathy. Conclusion: This clinical case refers to a previously healthy boy accidentallly diagnosed as dilated cardiomyopathy presenting with abdominal pain. Both echocardiogram and cardiac MS-CT 640 slices were suggestive of Noncompaction cardiomyopathy. Our purpose with this case report was to point out attention to this entity as an important and often misdiagnosed cause of dilated cardiomyopathy (Figure presented).